This commit was manufactured by cvs2svn to create tag 'help'.help

12 files changed, 0 insertions, 7617 deletions

diff --git a/ext/pcre/pcrelib/doc/Tech.Notes b/ext/pcre/pcrelib/doc/Tech.Notes
deleted file mode 100644
index 7b96e5b60e..0000000000
--- a/ext/pcre/pcrelib/doc/Tech.Notes
+++ /dev/null
@@ -1,243 +0,0 @@
-Technical Notes about PCRE
---------------------------
-
-Many years ago I implemented some regular expression functions to an algorithm
-suggested by Martin Richards. These were not Unix-like in form, and were quite
-restricted in what they could do by comparison with Perl. The interesting part
-about the algorithm was that the amount of space required to hold the compiled
-form of an expression was known in advance. The code to apply an expression did
-not operate by backtracking, as the Henry Spencer and Perl code does, but
-instead checked all possibilities simultaneously by keeping a list of current
-states and checking all of them as it advanced through the subject string. (In
-the terminology of Jeffrey Friedl's book, it was a "DFA algorithm".) When the
-pattern was all used up, all remaining states were possible matches, and the
-one matching the longest subset of the subject string was chosen. This did not
-necessarily maximize the individual wild portions of the pattern, as is
-expected in Unix and Perl-style regular expressions.
-
-By contrast, the code originally written by Henry Spencer and subsequently
-heavily modified for Perl actually compiles the expression twice: once in a
-dummy mode in order to find out how much store will be needed, and then for
-real. The execution function operates by backtracking and maximizing (or,
-optionally, minimizing in Perl) the amount of the subject that matches
-individual wild portions of the pattern. This is an "NFA algorithm" in Friedl's
-terminology.
-
-For the set of functions that forms PCRE (which are unrelated to those
-mentioned above), I tried at first to invent an algorithm that used an amount
-of store bounded by a multiple of the number of characters in the pattern, to
-save on compiling time. However, because of the greater complexity in Perl
-regular expressions, I couldn't do this. In any case, a first pass through the
-pattern is needed, in order to find internal flag settings like (?i) at top
-level. So PCRE works by running a very degenerate first pass to calculate a
-maximum store size, and then a second pass to do the real compile - which may
-use a bit less than the predicted amount of store. The idea is that this is
-going to turn out faster because the first pass is degenerate and the second
-pass can just store stuff straight into the vector. It does make the compiling
-functions bigger, of course, but they have got quite big anyway to handle all
-the Perl stuff.
-
-The compiled form of a pattern is a vector of bytes, containing items of
-variable length. The first byte in an item is an opcode, and the length of the
-item is either implicit in the opcode or contained in the data bytes which
-follow it. A list of all the opcodes follows:
-
-Opcodes with no following data
-------------------------------
-
-These items are all just one byte long
-
-  OP_END                 end of pattern
-  OP_ANY                 match any character
-  OP_SOD                 match start of data: \A
-  OP_CIRC                ^ (start of data, or after \n in multiline)
-  OP_NOT_WORD_BOUNDARY   \W
-  OP_WORD_BOUNDARY       \w
-  OP_NOT_DIGIT           \D
-  OP_DIGIT               \d
-  OP_NOT_WHITESPACE      \S
-  OP_WHITESPACE          \s
-  OP_NOT_WORDCHAR        \W
-  OP_WORDCHAR            \w
-  OP_EODN                match end of data or \n at end: \Z
-  OP_EOD                 match end of data: \z
-  OP_DOLL                $ (end of data, or before \n in multiline)
-  OP_RECURSE             match the pattern recursively
-
-
-Repeating single characters
----------------------------
-
-The common repeats (*, +, ?) when applied to a single character appear as
-two-byte items using the following opcodes:
-
-  OP_STAR
-  OP_MINSTAR
-  OP_PLUS
-  OP_MINPLUS
-  OP_QUERY
-  OP_MINQUERY
-
-Those with "MIN" in their name are the minimizing versions. Each is followed by
-the character that is to be repeated. Other repeats make use of
-
-  OP_UPTO
-  OP_MINUPTO
-  OP_EXACT
-
-which are followed by a two-byte count (most significant first) and the
-repeated character. OP_UPTO matches from 0 to the given number. A repeat with a
-non-zero minimum and a fixed maximum is coded as an OP_EXACT followed by an
-OP_UPTO (or OP_MINUPTO).
-
-
-Repeating character types
--------------------------
-
-Repeats of things like \d are done exactly as for single characters, except
-that instead of a character, the opcode for the type is stored in the data
-byte. The opcodes are:
-
-  OP_TYPESTAR
-  OP_TYPEMINSTAR
-  OP_TYPEPLUS
-  OP_TYPEMINPLUS
-  OP_TYPEQUERY
-  OP_TYPEMINQUERY
-  OP_TYPEUPTO
-  OP_TYPEMINUPTO
-  OP_TYPEEXACT
-
-
-Matching a character string
----------------------------
-
-The OP_CHARS opcode is followed by a one-byte count and then that number of
-characters. If there are more than 255 characters in sequence, successive
-instances of OP_CHARS are used.
-
-
-Character classes
------------------
-
-OP_CLASS is used for a character class, provided there are at least two
-characters in the class. If there is only one character, OP_CHARS is used for a
-positive class, and OP_NOT for a negative one (that is, for something like
-[^a]). Another set of repeating opcodes (OP_NOTSTAR etc.) are used for a
-repeated, negated, single-character class. The normal ones (OP_STAR etc.) are
-used for a repeated positive single-character class.
-
-OP_CLASS is followed by a 32-byte bit map containing a 1 bit for every
-character that is acceptable. The bits are counted from the least significant
-end of each byte.
-
-
-Back references
----------------
-
-OP_REF is followed by a single byte containing the reference number.
-
-
-Repeating character classes and back references
------------------------------------------------
-
-Single-character classes are handled specially (see above). This applies to
-OP_CLASS and OP_REF. In both cases, the repeat information follows the base
-item. The matching code looks at the following opcode to see if it is one of
-
-  OP_CRSTAR
-  OP_CRMINSTAR
-  OP_CRPLUS
-  OP_CRMINPLUS
-  OP_CRQUERY
-  OP_CRMINQUERY
-  OP_CRRANGE
-  OP_CRMINRANGE
-
-All but the last two are just single-byte items. The others are followed by
-four bytes of data, comprising the minimum and maximum repeat counts.
-
-
-Brackets and alternation
-------------------------
-
-A pair of non-capturing (round) brackets is wrapped round each expression at
-compile time, so alternation always happens in the context of brackets.
-Non-capturing brackets use the opcode OP_BRA, while capturing brackets use
-OP_BRA+1, OP_BRA+2, etc. [Note for North Americans: "bracket" to some English
-speakers, including myself, can be round, square, curly, or pointy. Hence this
-usage.]
-
-A bracket opcode is followed by two bytes which give the offset to the next
-alternative OP_ALT or, if there aren't any branches, to the matching KET
-opcode. Each OP_ALT is followed by two bytes giving the offset to the next one,
-or to the KET opcode.
-
-OP_KET is used for subpatterns that do not repeat indefinitely, while
-OP_KETRMIN and OP_KETRMAX are used for indefinite repetitions, minimally or
-maximally respectively. All three are followed by two bytes giving (as a
-positive number) the offset back to the matching BRA opcode.
-
-If a subpattern is quantified such that it is permitted to match zero times, it
-is preceded by one of OP_BRAZERO or OP_BRAMINZERO. These are single-byte
-opcodes which tell the matcher that skipping this subpattern entirely is a
-valid branch.
-
-A subpattern with an indefinite maximum repetition is replicated in the
-compiled data its minimum number of times (or once with a BRAZERO if the
-minimum is zero), with the final copy terminating with a KETRMIN or KETRMAX as
-appropriate.
-
-A subpattern with a bounded maximum repetition is replicated in a nested
-fashion up to the maximum number of times, with BRAZERO or BRAMINZERO before
-each replication after the minimum, so that, for example, (abc){2,5} is
-compiled as (abc)(abc)((abc)((abc)(abc)?)?)?. The 200-bracket limit does not
-apply to these internally generated brackets.
-
-
-Assertions
-----------
-
-Forward assertions are just like other subpatterns, but starting with one of
-the opcodes OP_ASSERT or OP_ASSERT_NOT. Backward assertions use the opcodes
-OP_ASSERTBACK and OP_ASSERTBACK_NOT, and the first opcode inside the assertion
-is OP_REVERSE, followed by a two byte count of the number of characters to move
-back the pointer in the subject string. When operating in UTF-8 mode, the count
-is a character count rather than a byte count. A separate count is present in
-each alternative of a lookbehind assertion, allowing them to have different
-fixed lengths.
-
-
-Once-only subpatterns
----------------------
-
-These are also just like other subpatterns, but they start with the opcode
-OP_ONCE.
-
-
-Conditional subpatterns
------------------------
-
-These are like other subpatterns, but they start with the opcode OP_COND. If
-the condition is a back reference, this is stored at the start of the
-subpattern using the opcode OP_CREF followed by one byte containing the
-reference number. Otherwise, a conditional subpattern will always start with
-one of the assertions.
-
-
-Changing options
-----------------
-
-If any of the /i, /m, or /s options are changed within a parenthesized group,
-an OP_OPT opcode is compiled, followed by one byte containing the new settings
-of these flags. If there are several alternatives in a group, there is an
-occurrence of OP_OPT at the start of all those following the first options
-change, to set appropriate options for the start of the alternative.
-Immediately after the end of the group there is another such item to reset the
-flags to their previous values. Other changes of flag within the pattern can be
-handled entirely at compile time, and so do not cause anything to be put into
-the compiled data.
-
-
-Philip Hazel
-August 2000
diff --git a/ext/pcre/pcrelib/doc/pcre.3 b/ext/pcre/pcrelib/doc/pcre.3
deleted file mode 100644
index fc204453c7..0000000000
--- a/ext/pcre/pcrelib/doc/pcre.3
+++ /dev/null
@@ -1,1810 +0,0 @@
-.TH PCRE 3
-.SH NAME
-pcre - Perl-compatible regular expressions.
-.SH SYNOPSIS
-.B #include <pcre.h>
-.PP
-.SM
-.br
-.B pcre *pcre_compile(const char *\fIpattern\fR, int \fIoptions\fR,
-.ti +5n
-.B const char **\fIerrptr\fR, int *\fIerroffset\fR,
-.ti +5n
-.B const unsigned char *\fItableptr\fR);
-.PP
-.br
-.B pcre_extra *pcre_study(const pcre *\fIcode\fR, int \fIoptions\fR,
-.ti +5n
-.B const char **\fIerrptr\fR);
-.PP
-.br
-.B int pcre_exec(const pcre *\fIcode\fR, "const pcre_extra *\fIextra\fR,"
-.ti +5n
-.B "const char *\fIsubject\fR," int \fIlength\fR, int \fIstartoffset\fR,
-.ti +5n
-.B int \fIoptions\fR, int *\fIovector\fR, int \fIovecsize\fR);
-.PP
-.br
-.B int pcre_copy_substring(const char *\fIsubject\fR, int *\fIovector\fR,
-.ti +5n
-.B int \fIstringcount\fR, int \fIstringnumber\fR, char *\fIbuffer\fR,
-.ti +5n
-.B int \fIbuffersize\fR);
-.PP
-.br
-.B int pcre_get_substring(const char *\fIsubject\fR, int *\fIovector\fR,
-.ti +5n
-.B int \fIstringcount\fR, int \fIstringnumber\fR,
-.ti +5n
-.B const char **\fIstringptr\fR);
-.PP
-.br
-.B int pcre_get_substring_list(const char *\fIsubject\fR,
-.ti +5n
-.B int *\fIovector\fR, int \fIstringcount\fR, "const char ***\fIlistptr\fR);"
-.PP
-.br
-.B void pcre_free_substring(const char *\fIstringptr\fR);
-.PP
-.br
-.B void pcre_free_substring_list(const char **\fIstringptr\fR);
-.PP
-.br
-.B const unsigned char *pcre_maketables(void);
-.PP
-.br
-.B int pcre_fullinfo(const pcre *\fIcode\fR, "const pcre_extra *\fIextra\fR,"
-.ti +5n
-.B int \fIwhat\fR, void *\fIwhere\fR);
-.PP
-.br
-.B int pcre_info(const pcre *\fIcode\fR, int *\fIoptptr\fR, int
-.B *\fIfirstcharptr\fR);
-.PP
-.br
-.B char *pcre_version(void);
-.PP
-.br
-.B void *(*pcre_malloc)(size_t);
-.PP
-.br
-.B void (*pcre_free)(void *);
-
-
-
-.SH DESCRIPTION
-The PCRE library is a set of functions that implement regular expression
-pattern matching using the same syntax and semantics as Perl 5, with just a few
-differences (see below). The current implementation corresponds to Perl 5.005,
-with some additional features from later versions. This includes some
-experimental, incomplete support for UTF-8 encoded strings. Details of exactly
-what is and what is not supported are given below.
-
-PCRE has its own native API, which is described in this document. There is also
-a set of wrapper functions that correspond to the POSIX regular expression API.
-These are described in the \fBpcreposix\fR documentation.
-
-The native API function prototypes are defined in the header file \fBpcre.h\fR,
-and on Unix systems the library itself is called \fBlibpcre.a\fR, so can be
-accessed by adding \fB-lpcre\fR to the command for linking an application which
-calls it. The header file defines the macros PCRE_MAJOR and PCRE_MINOR to
-contain the major and minor release numbers for the library. Applications can
-use these to include support for different releases.
-
-The functions \fBpcre_compile()\fR, \fBpcre_study()\fR, and \fBpcre_exec()\fR
-are used for compiling and matching regular expressions.
-
-The functions \fBpcre_copy_substring()\fR, \fBpcre_get_substring()\fR, and
-\fBpcre_get_substring_list()\fR are convenience functions for extracting
-captured substrings from a matched subject string; \fBpcre_free_substring()\fR
-and \fBpcre_free_substring_list()\fR are also provided, to free the memory used
-for extracted strings.
-
-The function \fBpcre_maketables()\fR is used (optionally) to build a set of
-character tables in the current locale for passing to \fBpcre_compile()\fR.
-
-The function \fBpcre_fullinfo()\fR is used to find out information about a
-compiled pattern; \fBpcre_info()\fR is an obsolete version which returns only
-some of the available information, but is retained for backwards compatibility.
-The function \fBpcre_version()\fR returns a pointer to a string containing the
-version of PCRE and its date of release.
-
-The global variables \fBpcre_malloc\fR and \fBpcre_free\fR initially contain
-the entry points of the standard \fBmalloc()\fR and \fBfree()\fR functions
-respectively. PCRE calls the memory management functions via these variables,
-so a calling program can replace them if it wishes to intercept the calls. This
-should be done before calling any PCRE functions.
-
-
-.SH MULTI-THREADING
-The PCRE functions can be used in multi-threading applications, with the
-proviso that the memory management functions pointed to by \fBpcre_malloc\fR
-and \fBpcre_free\fR are shared by all threads.
-
-The compiled form of a regular expression is not altered during matching, so
-the same compiled pattern can safely be used by several threads at once.
-
-
-.SH COMPILING A PATTERN
-The function \fBpcre_compile()\fR is called to compile a pattern into an
-internal form. The pattern is a C string terminated by a binary zero, and
-is passed in the argument \fIpattern\fR. A pointer to a single block of memory
-that is obtained via \fBpcre_malloc\fR is returned. This contains the
-compiled code and related data. The \fBpcre\fR type is defined for this for
-convenience, but in fact \fBpcre\fR is just a typedef for \fBvoid\fR, since the
-contents of the block are not externally defined. It is up to the caller to
-free the memory when it is no longer required.
-.PP
-The size of a compiled pattern is roughly proportional to the length of the
-pattern string, except that each character class (other than those containing
-just a single character, negated or not) requires 33 bytes, and repeat
-quantifiers with a minimum greater than one or a bounded maximum cause the
-relevant portions of the compiled pattern to be replicated.
-.PP
-The \fIoptions\fR argument contains independent bits that affect the
-compilation. It should be zero if no options are required. Some of the options,
-in particular, those that are compatible with Perl, can also be set and unset
-from within the pattern (see the detailed description of regular expressions
-below). For these options, the contents of the \fIoptions\fR argument specifies
-their initial settings at the start of compilation and execution. The
-PCRE_ANCHORED option can be set at the time of matching as well as at compile
-time.
-.PP
-If \fIerrptr\fR is NULL, \fBpcre_compile()\fR returns NULL immediately.
-Otherwise, if compilation of a pattern fails, \fBpcre_compile()\fR returns
-NULL, and sets the variable pointed to by \fIerrptr\fR to point to a textual
-error message. The offset from the start of the pattern to the character where
-the error was discovered is placed in the variable pointed to by
-\fIerroffset\fR, which must not be NULL. If it is, an immediate error is given.
-.PP
-If the final argument, \fItableptr\fR, is NULL, PCRE uses a default set of
-character tables which are built when it is compiled, using the default C
-locale. Otherwise, \fItableptr\fR must be the result of a call to
-\fBpcre_maketables()\fR. See the section on locale support below.
-.PP
-The following option bits are defined in the header file:
-
-  PCRE_ANCHORED
-
-If this bit is set, the pattern is forced to be "anchored", that is, it is
-constrained to match only at the start of the string which is being searched
-(the "subject string"). This effect can also be achieved by appropriate
-constructs in the pattern itself, which is the only way to do it in Perl.
-
-  PCRE_CASELESS
-
-If this bit is set, letters in the pattern match both upper and lower case
-letters. It is equivalent to Perl's /i option.
-
-  PCRE_DOLLAR_ENDONLY
-
-If this bit is set, a dollar metacharacter in the pattern matches only at the
-end of the subject string. Without this option, a dollar also matches
-immediately before the final character if it is a newline (but not before any
-other newlines). The PCRE_DOLLAR_ENDONLY option is ignored if PCRE_MULTILINE is
-set. There is no equivalent to this option in Perl.
-
-  PCRE_DOTALL
-
-If this bit is set, a dot metacharater in the pattern matches all characters,
-including newlines. Without it, newlines are excluded. This option is
-equivalent to Perl's /s option. A negative class such as [^a] always matches a
-newline character, independent of the setting of this option.
-
-  PCRE_EXTENDED
-
-If this bit is set, whitespace data characters in the pattern are totally
-ignored except when escaped or inside a character class, and characters between
-an unescaped # outside a character class and the next newline character,
-inclusive, are also ignored. This is equivalent to Perl's /x option, and makes
-it possible to include comments inside complicated patterns. Note, however,
-that this applies only to data characters. Whitespace characters may never
-appear within special character sequences in a pattern, for example within the
-sequence (?( which introduces a conditional subpattern.
-
-  PCRE_EXTRA
-
-This option was invented in order to turn on additional functionality of PCRE
-that is incompatible with Perl, but it is currently of very little use. When
-set, any backslash in a pattern that is followed by a letter that has no
-special meaning causes an error, thus reserving these combinations for future
-expansion. By default, as in Perl, a backslash followed by a letter with no
-special meaning is treated as a literal. There are at present no other features
-controlled by this option. It can also be set by a (?X) option setting within a
-pattern.
-
-  PCRE_MULTILINE
-
-By default, PCRE treats the subject string as consisting of a single "line" of
-characters (even if it actually contains several newlines). The "start of line"
-metacharacter (^) matches only at the start of the string, while the "end of
-line" metacharacter ($) matches only at the end of the string, or before a
-terminating newline (unless PCRE_DOLLAR_ENDONLY is set). This is the same as
-Perl.
-
-When PCRE_MULTILINE it is set, the "start of line" and "end of line" constructs
-match immediately following or immediately before any newline in the subject
-string, respectively, as well as at the very start and end. This is equivalent
-to Perl's /m option. If there are no "\\n" characters in a subject string, or
-no occurrences of ^ or $ in a pattern, setting PCRE_MULTILINE has no
-effect.
-
-  PCRE_UNGREEDY
-
-This option inverts the "greediness" of the quantifiers so that they are not
-greedy by default, but become greedy if followed by "?". It is not compatible
-with Perl. It can also be set by a (?U) option setting within the pattern.
-
-  PCRE_UTF8
-
-This option causes PCRE to regard both the pattern and the subject as strings
-of UTF-8 characters instead of just byte strings. However, it is available only
-if PCRE has been built to include UTF-8 support. If not, the use of this option
-provokes an error. Support for UTF-8 is new, experimental, and incomplete.
-Details of exactly what it entails are given below.
-
-
-.SH STUDYING A PATTERN
-When a pattern is going to be used several times, it is worth spending more
-time analyzing it in order to speed up the time taken for matching. The
-function \fBpcre_study()\fR takes a pointer to a compiled pattern as its first
-argument, and returns a pointer to a \fBpcre_extra\fR block (another \fBvoid\fR
-typedef) containing additional information about the pattern; this can be
-passed to \fBpcre_exec()\fR. If no additional information is available, NULL
-is returned.
-
-The second argument contains option bits. At present, no options are defined
-for \fBpcre_study()\fR, and this argument should always be zero.
-
-The third argument for \fBpcre_study()\fR is a pointer to an error message. If
-studying succeeds (even if no data is returned), the variable it points to is
-set to NULL. Otherwise it points to a textual error message.
-
-At present, studying a pattern is useful only for non-anchored patterns that do
-not have a single fixed starting character. A bitmap of possible starting
-characters is created.
-
-
-.SH LOCALE SUPPORT
-PCRE handles caseless matching, and determines whether characters are letters,
-digits, or whatever, by reference to a set of tables. The library contains a
-default set of tables which is created in the default C locale when PCRE is
-compiled. This is used when the final argument of \fBpcre_compile()\fR is NULL,
-and is sufficient for many applications.
-
-An alternative set of tables can, however, be supplied. Such tables are built
-by calling the \fBpcre_maketables()\fR function, which has no arguments, in the
-relevant locale. The result can then be passed to \fBpcre_compile()\fR as often
-as necessary. For example, to build and use tables that are appropriate for the
-French locale (where accented characters with codes greater than 128 are
-treated as letters), the following code could be used:
-
-  setlocale(LC_CTYPE, "fr");
-  tables = pcre_maketables();
-  re = pcre_compile(..., tables);
-
-The tables are built in memory that is obtained via \fBpcre_malloc\fR. The
-pointer that is passed to \fBpcre_compile\fR is saved with the compiled
-pattern, and the same tables are used via this pointer by \fBpcre_study()\fR
-and \fBpcre_exec()\fR. Thus for any single pattern, compilation, studying and
-matching all happen in the same locale, but different patterns can be compiled
-in different locales. It is the caller's responsibility to ensure that the
-memory containing the tables remains available for as long as it is needed.
-
-
-.SH INFORMATION ABOUT A PATTERN
-The \fBpcre_fullinfo()\fR function returns information about a compiled
-pattern. It replaces the obsolete \fBpcre_info()\fR function, which is
-nevertheless retained for backwards compability (and is documented below).
-
-The first argument for \fBpcre_fullinfo()\fR is a pointer to the compiled
-pattern. The second argument is the result of \fBpcre_study()\fR, or NULL if
-the pattern was not studied. The third argument specifies which piece of
-information is required, while the fourth argument is a pointer to a variable
-to receive the data. The yield of the function is zero for success, or one of
-the following negative numbers:
-
-  PCRE_ERROR_NULL       the argument \fIcode\fR was NULL
-                        the argument \fIwhere\fR was NULL
-  PCRE_ERROR_BADMAGIC   the "magic number" was not found
-  PCRE_ERROR_BADOPTION  the value of \fIwhat\fR was invalid
-
-The possible values for the third argument are defined in \fBpcre.h\fR, and are
-as follows:
-
-  PCRE_INFO_OPTIONS
-
-Return a copy of the options with which the pattern was compiled. The fourth
-argument should point to au \fBunsigned long int\fR variable. These option bits
-are those specified in the call to \fBpcre_compile()\fR, modified by any
-top-level option settings within the pattern itself, and with the PCRE_ANCHORED
-bit forcibly set if the form of the pattern implies that it can match only at
-the start of a subject string.
-
-  PCRE_INFO_SIZE
-
-Return the size of the compiled pattern, that is, the value that was passed as
-the argument to \fBpcre_malloc()\fR when PCRE was getting memory in which to
-place the compiled data. The fourth argument should point to a \fBsize_t\fR
-variable.
-
-  PCRE_INFO_CAPTURECOUNT
-
-Return the number of capturing subpatterns in the pattern. The fourth argument
-should point to an \fbint\fR variable.
-
-  PCRE_INFO_BACKREFMAX
-
-Return the number of the highest back reference in the pattern. The fourth
-argument should point to an \fBint\fR variable. Zero is returned if there are
-no back references.
-
-  PCRE_INFO_FIRSTCHAR
-
-Return information about the first character of any matched string, for a
-non-anchored pattern. If there is a fixed first character, e.g. from a pattern
-such as (cat|cow|coyote), it is returned in the integer pointed to by
-\fIwhere\fR. Otherwise, if either
-
-(a) the pattern was compiled with the PCRE_MULTILINE option, and every branch
-starts with "^", or
-
-(b) every branch of the pattern starts with ".*" and PCRE_DOTALL is not set
-(if it were set, the pattern would be anchored),
-
--1 is returned, indicating that the pattern matches only at the start of a
-subject string or after any "\\n" within the string. Otherwise -2 is returned.
-For anchored patterns, -2 is returned.
-
-  PCRE_INFO_FIRSTTABLE
-
-If the pattern was studied, and this resulted in the construction of a 256-bit
-table indicating a fixed set of characters for the first character in any
-matching string, a pointer to the table is returned. Otherwise NULL is
-returned. The fourth argument should point to an \fBunsigned char *\fR
-variable.
-
-  PCRE_INFO_LASTLITERAL
-
-For a non-anchored pattern, return the value of the rightmost literal character
-which must exist in any matched string, other than at its start. The fourth
-argument should point to an \fBint\fR variable. If there is no such character,
-or if the pattern is anchored, -1 is returned. For example, for the pattern
-/a\\d+z\\d+/ the returned value is 'z'.
-
-The \fBpcre_info()\fR function is now obsolete because its interface is too
-restrictive to return all the available data about a compiled pattern. New
-programs should use \fBpcre_fullinfo()\fR instead. The yield of
-\fBpcre_info()\fR is the number of capturing subpatterns, or one of the
-following negative numbers:
-
-  PCRE_ERROR_NULL       the argument \fIcode\fR was NULL
-  PCRE_ERROR_BADMAGIC   the "magic number" was not found
-
-If the \fIoptptr\fR argument is not NULL, a copy of the options with which the
-pattern was compiled is placed in the integer it points to (see
-PCRE_INFO_OPTIONS above).
-
-If the pattern is not anchored and the \fIfirstcharptr\fR argument is not NULL,
-it is used to pass back information about the first character of any matched
-string (see PCRE_INFO_FIRSTCHAR above).
-
-
-.SH MATCHING A PATTERN
-The function \fBpcre_exec()\fR is called to match a subject string against a
-pre-compiled pattern, which is passed in the \fIcode\fR argument. If the
-pattern has been studied, the result of the study should be passed in the
-\fIextra\fR argument. Otherwise this must be NULL.
-
-The PCRE_ANCHORED option can be passed in the \fIoptions\fR argument, whose
-unused bits must be zero. However, if a pattern was compiled with
-PCRE_ANCHORED, or turned out to be anchored by virtue of its contents, it
-cannot be made unachored at matching time.
-
-There are also three further options that can be set only at matching time:
-
-  PCRE_NOTBOL
-
-The first character of the string is not the beginning of a line, so the
-circumflex metacharacter should not match before it. Setting this without
-PCRE_MULTILINE (at compile time) causes circumflex never to match.
-
-  PCRE_NOTEOL
-
-The end of the string is not the end of a line, so the dollar metacharacter
-should not match it nor (except in multiline mode) a newline immediately before
-it. Setting this without PCRE_MULTILINE (at compile time) causes dollar never
-to match.
-
-  PCRE_NOTEMPTY
-
-An empty string is not considered to be a valid match if this option is set. If
-there are alternatives in the pattern, they are tried. If all the alternatives
-match the empty string, the entire match fails. For example, if the pattern
-
-  a?b?
-
-is applied to a string not beginning with "a" or "b", it matches the empty
-string at the start of the subject. With PCRE_NOTEMPTY set, this match is not
-valid, so PCRE searches further into the string for occurrences of "a" or "b".
-
-Perl has no direct equivalent of PCRE_NOTEMPTY, but it does make a special case
-of a pattern match of the empty string within its \fBsplit()\fR function, and
-when using the /g modifier. It is possible to emulate Perl's behaviour after
-matching a null string by first trying the match again at the same offset with
-PCRE_NOTEMPTY set, and then if that fails by advancing the starting offset (see
-below) and trying an ordinary match again.
-
-The subject string is passed as a pointer in \fIsubject\fR, a length in
-\fIlength\fR, and a starting offset in \fIstartoffset\fR. Unlike the pattern
-string, it may contain binary zero characters. When the starting offset is
-zero, the search for a match starts at the beginning of the subject, and this
-is by far the most common case.
-
-A non-zero starting offset is useful when searching for another match in the
-same subject by calling \fBpcre_exec()\fR again after a previous success.
-Setting \fIstartoffset\fR differs from just passing over a shortened string and
-setting PCRE_NOTBOL in the case of a pattern that begins with any kind of
-lookbehind. For example, consider the pattern
-
-  \\Biss\\B
-
-which finds occurrences of "iss" in the middle of words. (\\B matches only if
-the current position in the subject is not a word boundary.) When applied to
-the string "Mississipi" the first call to \fBpcre_exec()\fR finds the first
-occurrence. If \fBpcre_exec()\fR is called again with just the remainder of the
-subject, namely "issipi", it does not match, because \\B is always false at the
-start of the subject, which is deemed to be a word boundary. However, if
-\fBpcre_exec()\fR is passed the entire string again, but with \fIstartoffset\fR
-set to 4, it finds the second occurrence of "iss" because it is able to look
-behind the starting point to discover that it is preceded by a letter.
-
-If a non-zero starting offset is passed when the pattern is anchored, one
-attempt to match at the given offset is tried. This can only succeed if the
-pattern does not require the match to be at the start of the subject.
-
-In general, a pattern matches a certain portion of the subject, and in
-addition, further substrings from the subject may be picked out by parts of the
-pattern. Following the usage in Jeffrey Friedl's book, this is called
-"capturing" in what follows, and the phrase "capturing subpattern" is used for
-a fragment of a pattern that picks out a substring. PCRE supports several other
-kinds of parenthesized subpattern that do not cause substrings to be captured.
-
-Captured substrings are returned to the caller via a vector of integer offsets
-whose address is passed in \fIovector\fR. The number of elements in the vector
-is passed in \fIovecsize\fR. The first two-thirds of the vector is used to pass
-back captured substrings, each substring using a pair of integers. The
-remaining third of the vector is used as workspace by \fBpcre_exec()\fR while
-matching capturing subpatterns, and is not available for passing back
-information. The length passed in \fIovecsize\fR should always be a multiple of
-three. If it is not, it is rounded down.
-
-When a match has been successful, information about captured substrings is
-returned in pairs of integers, starting at the beginning of \fIovector\fR, and
-continuing up to two-thirds of its length at the most. The first element of a
-pair is set to the offset of the first character in a substring, and the second
-is set to the offset of the first character after the end of a substring. The
-first pair, \fIovector[0]\fR and \fIovector[1]\fR, identify the portion of the
-subject string matched by the entire pattern. The next pair is used for the
-first capturing subpattern, and so on. The value returned by \fBpcre_exec()\fR
-is the number of pairs that have been set. If there are no capturing
-subpatterns, the return value from a successful match is 1, indicating that
-just the first pair of offsets has been set.
-
-Some convenience functions are provided for extracting the captured substrings
-as separate strings. These are described in the following section.
-
-It is possible for an capturing subpattern number \fIn+1\fR to match some
-part of the subject when subpattern \fIn\fR has not been used at all. For
-example, if the string "abc" is matched against the pattern (a|(z))(bc)
-subpatterns 1 and 3 are matched, but 2 is not. When this happens, both offset
-values corresponding to the unused subpattern are set to -1.
-
-If a capturing subpattern is matched repeatedly, it is the last portion of the
-string that it matched that gets returned.
-
-If the vector is too small to hold all the captured substrings, it is used as
-far as possible (up to two-thirds of its length), and the function returns a
-value of zero. In particular, if the substring offsets are not of interest,
-\fBpcre_exec()\fR may be called with \fIovector\fR passed as NULL and
-\fIovecsize\fR as zero. However, if the pattern contains back references and
-the \fIovector\fR isn't big enough to remember the related substrings, PCRE has
-to get additional memory for use during matching. Thus it is usually advisable
-to supply an \fIovector\fR.
-
-Note that \fBpcre_info()\fR can be used to find out how many capturing
-subpatterns there are in a compiled pattern. The smallest size for
-\fIovector\fR that will allow for \fIn\fR captured substrings in addition to
-the offsets of the substring matched by the whole pattern is (\fIn\fR+1)*3.
-
-If \fBpcre_exec()\fR fails, it returns a negative number. The following are
-defined in the header file:
-
-  PCRE_ERROR_NOMATCH        (-1)
-
-The subject string did not match the pattern.
-
-  PCRE_ERROR_NULL           (-2)
-
-Either \fIcode\fR or \fIsubject\fR was passed as NULL, or \fIovector\fR was
-NULL and \fIovecsize\fR was not zero.
-
-  PCRE_ERROR_BADOPTION      (-3)
-
-An unrecognized bit was set in the \fIoptions\fR argument.
-
-  PCRE_ERROR_BADMAGIC       (-4)
-
-PCRE stores a 4-byte "magic number" at the start of the compiled code, to catch
-the case when it is passed a junk pointer. This is the error it gives when the
-magic number isn't present.
-
-  PCRE_ERROR_UNKNOWN_NODE   (-5)
-
-While running the pattern match, an unknown item was encountered in the
-compiled pattern. This error could be caused by a bug in PCRE or by overwriting
-of the compiled pattern.
-
-  PCRE_ERROR_NOMEMORY       (-6)
-
-If a pattern contains back references, but the \fIovector\fR that is passed to
-\fBpcre_exec()\fR is not big enough to remember the referenced substrings, PCRE
-gets a block of memory at the start of matching to use for this purpose. If the
-call via \fBpcre_malloc()\fR fails, this error is given. The memory is freed at
-the end of matching.
-
-
-.SH EXTRACTING CAPTURED SUBSTRINGS
-Captured substrings can be accessed directly by using the offsets returned by
-\fBpcre_exec()\fR in \fIovector\fR. For convenience, the functions
-\fBpcre_copy_substring()\fR, \fBpcre_get_substring()\fR, and
-\fBpcre_get_substring_list()\fR are provided for extracting captured substrings
-as new, separate, zero-terminated strings. A substring that contains a binary
-zero is correctly extracted and has a further zero added on the end, but the
-result does not, of course, function as a C string.
-
-The first three arguments are the same for all three functions: \fIsubject\fR
-is the subject string which has just been successfully matched, \fIovector\fR
-is a pointer to the vector of integer offsets that was passed to
-\fBpcre_exec()\fR, and \fIstringcount\fR is the number of substrings that
-were captured by the match, including the substring that matched the entire
-regular expression. This is the value returned by \fBpcre_exec\fR if it
-is greater than zero. If \fBpcre_exec()\fR returned zero, indicating that it
-ran out of space in \fIovector\fR, the value passed as \fIstringcount\fR should
-be the size of the vector divided by three.
-
-The functions \fBpcre_copy_substring()\fR and \fBpcre_get_substring()\fR
-extract a single substring, whose number is given as \fIstringnumber\fR. A
-value of zero extracts the substring that matched the entire pattern, while
-higher values extract the captured substrings. For \fBpcre_copy_substring()\fR,
-the string is placed in \fIbuffer\fR, whose length is given by
-\fIbuffersize\fR, while for \fBpcre_get_substring()\fR a new block of memory is
-obtained via \fBpcre_malloc\fR, and its address is returned via
-\fIstringptr\fR. The yield of the function is the length of the string, not
-including the terminating zero, or one of
-
-  PCRE_ERROR_NOMEMORY       (-6)
-
-The buffer was too small for \fBpcre_copy_substring()\fR, or the attempt to get
-memory failed for \fBpcre_get_substring()\fR.
-
-  PCRE_ERROR_NOSUBSTRING    (-7)
-
-There is no substring whose number is \fIstringnumber\fR.
-
-The \fBpcre_get_substring_list()\fR function extracts all available substrings
-and builds a list of pointers to them. All this is done in a single block of
-memory which is obtained via \fBpcre_malloc\fR. The address of the memory block
-is returned via \fIlistptr\fR, which is also the start of the list of string
-pointers. The end of the list is marked by a NULL pointer. The yield of the
-function is zero if all went well, or
-
-  PCRE_ERROR_NOMEMORY       (-6)
-
-if the attempt to get the memory block failed.
-
-When any of these functions encounter a substring that is unset, which can
-happen when capturing subpattern number \fIn+1\fR matches some part of the
-subject, but subpattern \fIn\fR has not been used at all, they return an empty
-string. This can be distinguished from a genuine zero-length substring by
-inspecting the appropriate offset in \fIovector\fR, which is negative for unset
-substrings.
-
-The two convenience functions \fBpcre_free_substring()\fR and
-\fBpcre_free_substring_list()\fR can be used to free the memory returned by
-a previous call of \fBpcre_get_substring()\fR or
-\fBpcre_get_substring_list()\fR, respectively. They do nothing more than call
-the function pointed to by \fBpcre_free\fR, which of course could be called
-directly from a C program. However, PCRE is used in some situations where it is
-linked via a special interface to another programming language which cannot use
-\fBpcre_free\fR directly; it is for these cases that the functions are
-provided.
-
-
-.SH LIMITATIONS
-There are some size limitations in PCRE but it is hoped that they will never in
-practice be relevant.
-The maximum length of a compiled pattern is 65539 (sic) bytes.
-All values in repeating quantifiers must be less than 65536.
-The maximum number of capturing subpatterns is 99.
-The maximum number of all parenthesized subpatterns, including capturing
-subpatterns, assertions, and other types of subpattern, is 200.
-
-The maximum length of a subject string is the largest positive number that an
-integer variable can hold. However, PCRE uses recursion to handle subpatterns
-and indefinite repetition. This means that the available stack space may limit
-the size of a subject string that can be processed by certain patterns.
-
-
-.SH DIFFERENCES FROM PERL
-The differences described here are with respect to Perl 5.005.
-
-1. By default, a whitespace character is any character that the C library
-function \fBisspace()\fR recognizes, though it is possible to compile PCRE with
-alternative character type tables. Normally \fBisspace()\fR matches space,
-formfeed, newline, carriage return, horizontal tab, and vertical tab. Perl 5
-no longer includes vertical tab in its set of whitespace characters. The \\v
-escape that was in the Perl documentation for a long time was never in fact
-recognized. However, the character itself was treated as whitespace at least
-up to 5.002. In 5.004 and 5.005 it does not match \\s.
-
-2. PCRE does not allow repeat quantifiers on lookahead assertions. Perl permits
-them, but they do not mean what you might think. For example, (?!a){3} does
-not assert that the next three characters are not "a". It just asserts that the
-next character is not "a" three times.
-
-3. Capturing subpatterns that occur inside negative lookahead assertions are
-counted, but their entries in the offsets vector are never set. Perl sets its
-numerical variables from any such patterns that are matched before the
-assertion fails to match something (thereby succeeding), but only if the
-negative lookahead assertion contains just one branch.
-
-4. Though binary zero characters are supported in the subject string, they are
-not allowed in a pattern string because it is passed as a normal C string,
-terminated by zero. The escape sequence "\\0" can be used in the pattern to
-represent a binary zero.
-
-5. The following Perl escape sequences are not supported: \\l, \\u, \\L, \\U,
-\\E, \\Q. In fact these are implemented by Perl's general string-handling and
-are not part of its pattern matching engine.
-
-6. The Perl \\G assertion is not supported as it is not relevant to single
-pattern matches.
-
-7. Fairly obviously, PCRE does not support the (?{code}) and (?p{code})
-constructions. However, there is some experimental support for recursive
-patterns using the non-Perl item (?R).
-
-8. There are at the time of writing some oddities in Perl 5.005_02 concerned
-with the settings of captured strings when part of a pattern is repeated. For
-example, matching "aba" against the pattern /^(a(b)?)+$/ sets $2 to the value
-"b", but matching "aabbaa" against /^(aa(bb)?)+$/ leaves $2 unset. However, if
-the pattern is changed to /^(aa(b(b))?)+$/ then $2 (and $3) are set.
-
-In Perl 5.004 $2 is set in both cases, and that is also true of PCRE. If in the
-future Perl changes to a consistent state that is different, PCRE may change to
-follow.
-
-9. Another as yet unresolved discrepancy is that in Perl 5.005_02 the pattern
-/^(a)?(?(1)a|b)+$/ matches the string "a", whereas in PCRE it does not.
-However, in both Perl and PCRE /^(a)?a/ matched against "a" leaves $1 unset.
-
-10. PCRE provides some extensions to the Perl regular expression facilities:
-
-(a) Although lookbehind assertions must match fixed length strings, each
-alternative branch of a lookbehind assertion can match a different length of
-string. Perl 5.005 requires them all to have the same length.
-
-(b) If PCRE_DOLLAR_ENDONLY is set and PCRE_MULTILINE is not set, the $ meta-
-character matches only at the very end of the string.
-
-(c) If PCRE_EXTRA is set, a backslash followed by a letter with no special
-meaning is faulted.
-
-(d) If PCRE_UNGREEDY is set, the greediness of the repetition quantifiers is
-inverted, that is, by default they are not greedy, but if followed by a
-question mark they are.
-
-(e) PCRE_ANCHORED can be used to force a pattern to be tried only at the start
-of the subject.
-
-(f) The PCRE_NOTBOL, PCRE_NOTEOL, and PCRE_NOTEMPTY options for
-\fBpcre_exec()\fR have no Perl equivalents.
-
-(g) The (?R) construct allows for recursive pattern matching (Perl 5.6 can do
-this using the (?p{code}) construct, which PCRE cannot of course support.)
-
-
-.SH REGULAR EXPRESSION DETAILS
-The syntax and semantics of the regular expressions supported by PCRE are
-described below. Regular expressions are also described in the Perl
-documentation and in a number of other books, some of which have copious
-examples. Jeffrey Friedl's "Mastering Regular Expressions", published by
-O'Reilly (ISBN 1-56592-257), covers them in great detail.
-
-The description here is intended as reference documentation. The basic
-operation of PCRE is on strings of bytes. However, there is the beginnings of
-some support for UTF-8 character strings. To use this support you must
-configure PCRE to include it, and then call \fBpcre_compile()\fR with the
-PCRE_UTF8 option. How this affects the pattern matching is described in the
-final section of this document.
-
-A regular expression is a pattern that is matched against a subject string from
-left to right. Most characters stand for themselves in a pattern, and match the
-corresponding characters in the subject. As a trivial example, the pattern
-
-  The quick brown fox
-
-matches a portion of a subject string that is identical to itself. The power of
-regular expressions comes from the ability to include alternatives and
-repetitions in the pattern. These are encoded in the pattern by the use of
-\fImeta-characters\fR, which do not stand for themselves but instead are
-interpreted in some special way.
-
-There are two different sets of meta-characters: those that are recognized
-anywhere in the pattern except within square brackets, and those that are
-recognized in square brackets. Outside square brackets, the meta-characters are
-as follows:
-
-  \\      general escape character with several uses
-  ^      assert start of subject (or line, in multiline mode)
-  $      assert end of subject (or line, in multiline mode)
-  .      match any character except newline (by default)
-  [      start character class definition
-  |      start of alternative branch
-  (      start subpattern
-  )      end subpattern
-  ?      extends the meaning of (
-         also 0 or 1 quantifier
-         also quantifier minimizer
-  *      0 or more quantifier
-  +      1 or more quantifier
-  {      start min/max quantifier
-
-Part of a pattern that is in square brackets is called a "character class". In
-a character class the only meta-characters are:
-
-  \\      general escape character
-  ^      negate the class, but only if the first character
-  -      indicates character range
-  ]      terminates the character class
-
-The following sections describe the use of each of the meta-characters.
-
-
-.SH BACKSLASH
-The backslash character has several uses. Firstly, if it is followed by a
-non-alphameric character, it takes away any special meaning that character may
-have. This use of backslash as an escape character applies both inside and
-outside character classes.
-
-For example, if you want to match a "*" character, you write "\\*" in the
-pattern. This applies whether or not the following character would otherwise be
-interpreted as a meta-character, so it is always safe to precede a
-non-alphameric with "\\" to specify that it stands for itself. In particular,
-if you want to match a backslash, you write "\\\\".
-
-If a pattern is compiled with the PCRE_EXTENDED option, whitespace in the
-pattern (other than in a character class) and characters between a "#" outside
-a character class and the next newline character are ignored. An escaping
-backslash can be used to include a whitespace or "#" character as part of the
-pattern.
-
-A second use of backslash provides a way of encoding non-printing characters
-in patterns in a visible manner. There is no restriction on the appearance of
-non-printing characters, apart from the binary zero that terminates a pattern,
-but when a pattern is being prepared by text editing, it is usually easier to
-use one of the following escape sequences than the binary character it
-represents:
-
-  \\a     alarm, that is, the BEL character (hex 07)
-  \\cx    "control-x", where x is any character
-  \\e     escape (hex 1B)
-  \\f     formfeed (hex 0C)
-  \\n     newline (hex 0A)
-  \\r     carriage return (hex 0D)
-  \\t     tab (hex 09)
-  \\xhh   character with hex code hh
-  \\ddd   character with octal code ddd, or backreference
-
-The precise effect of "\\cx" is as follows: if "x" is a lower case letter, it
-is converted to upper case. Then bit 6 of the character (hex 40) is inverted.
-Thus "\\cz" becomes hex 1A, but "\\c{" becomes hex 3B, while "\\c;" becomes hex
-7B.
-
-After "\\x", up to two hexadecimal digits are read (letters can be in upper or
-lower case).
-
-After "\\0" up to two further octal digits are read. In both cases, if there
-are fewer than two digits, just those that are present are used. Thus the
-sequence "\\0\\x\\07" specifies two binary zeros followed by a BEL character.
-Make sure you supply two digits after the initial zero if the character that
-follows is itself an octal digit.
-
-The handling of a backslash followed by a digit other than 0 is complicated.
-Outside a character class, PCRE reads it and any following digits as a decimal
-number. If the number is less than 10, or if there have been at least that many
-previous capturing left parentheses in the expression, the entire sequence is
-taken as a \fIback reference\fR. A description of how this works is given
-later, following the discussion of parenthesized subpatterns.
-
-Inside a character class, or if the decimal number is greater than 9 and there
-have not been that many capturing subpatterns, PCRE re-reads up to three octal
-digits following the backslash, and generates a single byte from the least
-significant 8 bits of the value. Any subsequent digits stand for themselves.
-For example:
-
-  \\040   is another way of writing a space
-  \\40    is the same, provided there are fewer than 40
-            previous capturing subpatterns
-  \\7     is always a back reference
-  \\11    might be a back reference, or another way of
-            writing a tab
-  \\011   is always a tab
-  \\0113  is a tab followed by the character "3"
-  \\113   is the character with octal code 113 (since there
-            can be no more than 99 back references)
-  \\377   is a byte consisting entirely of 1 bits
-  \\81    is either a back reference, or a binary zero
-            followed by the two characters "8" and "1"
-
-Note that octal values of 100 or greater must not be introduced by a leading
-zero, because no more than three octal digits are ever read.
-
-All the sequences that define a single byte value can be used both inside and
-outside character classes. In addition, inside a character class, the sequence
-"\\b" is interpreted as the backspace character (hex 08). Outside a character
-class it has a different meaning (see below).
-
-The third use of backslash is for specifying generic character types:
-
-  \\d     any decimal digit
-  \\D     any character that is not a decimal digit
-  \\s     any whitespace character
-  \\S     any character that is not a whitespace character
-  \\w     any "word" character
-  \\W     any "non-word" character
-
-Each pair of escape sequences partitions the complete set of characters into
-two disjoint sets. Any given character matches one, and only one, of each pair.
-
-A "word" character is any letter or digit or the underscore character, that is,
-any character which can be part of a Perl "word". The definition of letters and
-digits is controlled by PCRE's character tables, and may vary if locale-
-specific matching is taking place (see "Locale support" above). For example, in
-the "fr" (French) locale, some character codes greater than 128 are used for
-accented letters, and these are matched by \\w.
-
-These character type sequences can appear both inside and outside character
-classes. They each match one character of the appropriate type. If the current
-matching point is at the end of the subject string, all of them fail, since
-there is no character to match.
-
-The fourth use of backslash is for certain simple assertions. An assertion
-specifies a condition that has to be met at a particular point in a match,
-without consuming any characters from the subject string. The use of
-subpatterns for more complicated assertions is described below. The backslashed
-assertions are
-
-  \\b     word boundary
-  \\B     not a word boundary
-  \\A     start of subject (independent of multiline mode)
-  \\Z     end of subject or newline at end (independent of multiline mode)
-  \\z     end of subject (independent of multiline mode)
-
-These assertions may not appear in character classes (but note that "\\b" has a
-different meaning, namely the backspace character, inside a character class).
-
-A word boundary is a position in the subject string where the current character
-and the previous character do not both match \\w or \\W (i.e. one matches
-\\w and the other matches \\W), or the start or end of the string if the
-first or last character matches \\w, respectively.
-
-The \\A, \\Z, and \\z assertions differ from the traditional circumflex and
-dollar (described below) in that they only ever match at the very start and end
-of the subject string, whatever options are set. They are not affected by the
-PCRE_NOTBOL or PCRE_NOTEOL options. If the \fIstartoffset\fR argument of
-\fBpcre_exec()\fR is non-zero, \\A can never match. The difference between \\Z
-and \\z is that \\Z matches before a newline that is the last character of the
-string as well as at the end of the string, whereas \\z matches only at the
-end.
-
-
-.SH CIRCUMFLEX AND DOLLAR
-Outside a character class, in the default matching mode, the circumflex
-character is an assertion which is true only if the current matching point is
-at the start of the subject string. If the \fIstartoffset\fR argument of
-\fBpcre_exec()\fR is non-zero, circumflex can never match. Inside a character
-class, circumflex has an entirely different meaning (see below).
-
-Circumflex need not be the first character of the pattern if a number of
-alternatives are involved, but it should be the first thing in each alternative
-in which it appears if the pattern is ever to match that branch. If all
-possible alternatives start with a circumflex, that is, if the pattern is
-constrained to match only at the start of the subject, it is said to be an
-"anchored" pattern. (There are also other constructs that can cause a pattern
-to be anchored.)
-
-A dollar character is an assertion which is true only if the current matching
-point is at the end of the subject string, or immediately before a newline
-character that is the last character in the string (by default). Dollar need
-not be the last character of the pattern if a number of alternatives are
-involved, but it should be the last item in any branch in which it appears.
-Dollar has no special meaning in a character class.
-
-The meaning of dollar can be changed so that it matches only at the very end of
-the string, by setting the PCRE_DOLLAR_ENDONLY option at compile or matching
-time. This does not affect the \\Z assertion.
-
-The meanings of the circumflex and dollar characters are changed if the
-PCRE_MULTILINE option is set. When this is the case, they match immediately
-after and immediately before an internal "\\n" character, respectively, in
-addition to matching at the start and end of the subject string. For example,
-the pattern /^abc$/ matches the subject string "def\\nabc" in multiline mode,
-but not otherwise. Consequently, patterns that are anchored in single line mode
-because all branches start with "^" are not anchored in multiline mode, and a
-match for circumflex is possible when the \fIstartoffset\fR argument of
-\fBpcre_exec()\fR is non-zero. The PCRE_DOLLAR_ENDONLY option is ignored if
-PCRE_MULTILINE is set.
-
-Note that the sequences \\A, \\Z, and \\z can be used to match the start and
-end of the subject in both modes, and if all branches of a pattern start with
-\\A is it always anchored, whether PCRE_MULTILINE is set or not.
-
-
-.SH FULL STOP (PERIOD, DOT)
-Outside a character class, a dot in the pattern matches any one character in
-the subject, including a non-printing character, but not (by default) newline.
-If the PCRE_DOTALL option is set, dots match newlines as well. The handling of
-dot is entirely independent of the handling of circumflex and dollar, the only
-relationship being that they both involve newline characters. Dot has no
-special meaning in a character class.
-
-
-.SH SQUARE BRACKETS
-An opening square bracket introduces a character class, terminated by a closing
-square bracket. A closing square bracket on its own is not special. If a
-closing square bracket is required as a member of the class, it should be the
-first data character in the class (after an initial circumflex, if present) or
-escaped with a backslash.
-
-A character class matches a single character in the subject; the character must
-be in the set of characters defined by the class, unless the first character in
-the class is a circumflex, in which case the subject character must not be in
-the set defined by the class. If a circumflex is actually required as a member
-of the class, ensure it is not the first character, or escape it with a
-backslash.
-
-For example, the character class [aeiou] matches any lower case vowel, while
-[^aeiou] matches any character that is not a lower case vowel. Note that a
-circumflex is just a convenient notation for specifying the characters which
-are in the class by enumerating those that are not. It is not an assertion: it
-still consumes a character from the subject string, and fails if the current
-pointer is at the end of the string.
-
-When caseless matching is set, any letters in a class represent both their
-upper case and lower case versions, so for example, a caseless [aeiou] matches
-"A" as well as "a", and a caseless [^aeiou] does not match "A", whereas a
-caseful version would.
-
-The newline character is never treated in any special way in character classes,
-whatever the setting of the PCRE_DOTALL or PCRE_MULTILINE options is. A class
-such as [^a] will always match a newline.
-
-The minus (hyphen) character can be used to specify a range of characters in a
-character class. For example, [d-m] matches any letter between d and m,
-inclusive. If a minus character is required in a class, it must be escaped with
-a backslash or appear in a position where it cannot be interpreted as
-indicating a range, typically as the first or last character in the class.
-
-It is not possible to have the literal character "]" as the end character of a
-range. A pattern such as [W-]46] is interpreted as a class of two characters
-("W" and "-") followed by a literal string "46]", so it would match "W46]" or
-"-46]". However, if the "]" is escaped with a backslash it is interpreted as
-the end of range, so [W-\\]46] is interpreted as a single class containing a
-range followed by two separate characters. The octal or hexadecimal
-representation of "]" can also be used to end a range.
-
-Ranges operate in ASCII collating sequence. They can also be used for
-characters specified numerically, for example [\\000-\\037]. If a range that
-includes letters is used when caseless matching is set, it matches the letters
-in either case. For example, [W-c] is equivalent to [][\\^_`wxyzabc], matched
-caselessly, and if character tables for the "fr" locale are in use,
-[\\xc8-\\xcb] matches accented E characters in both cases.
-
-The character types \\d, \\D, \\s, \\S, \\w, and \\W may also appear in a
-character class, and add the characters that they match to the class. For
-example, [\\dABCDEF] matches any hexadecimal digit. A circumflex can
-conveniently be used with the upper case character types to specify a more
-restricted set of characters than the matching lower case type. For example,
-the class [^\\W_] matches any letter or digit, but not underscore.
-
-All non-alphameric characters other than \\, -, ^ (at the start) and the
-terminating ] are non-special in character classes, but it does no harm if they
-are escaped.
-
-
-.SH POSIX CHARACTER CLASSES
-Perl 5.6 (not yet released at the time of writing) is going to support the
-POSIX notation for character classes, which uses names enclosed by [: and :]
-within the enclosing square brackets. PCRE supports this notation. For example,
-
-  [01[:alpha:]%]
-
-matches "0", "1", any alphabetic character, or "%". The supported class names
-are
-
-  alnum    letters and digits
-  alpha    letters
-  ascii    character codes 0 - 127
-  cntrl    control characters
-  digit    decimal digits (same as \\d)
-  graph    printing characters, excluding space
-  lower    lower case letters
-  print    printing characters, including space
-  punct    printing characters, excluding letters and digits
-  space    white space (same as \\s)
-  upper    upper case letters
-  word     "word" characters (same as \\w)
-  xdigit   hexadecimal digits
-
-The names "ascii" and "word" are Perl extensions. Another Perl extension is
-negation, which is indicated by a ^ character after the colon. For example,
-
-  [12[:^digit:]]
-
-matches "1", "2", or any non-digit. PCRE (and Perl) also recogize the POSIX
-syntax [.ch.] and [=ch=] where "ch" is a "collating element", but these are not
-supported, and an error is given if they are encountered.
-
-
-.SH VERTICAL BAR
-Vertical bar characters are used to separate alternative patterns. For example,
-the pattern
-
-  gilbert|sullivan
-
-matches either "gilbert" or "sullivan". Any number of alternatives may appear,
-and an empty alternative is permitted (matching the empty string).
-The matching process tries each alternative in turn, from left to right,
-and the first one that succeeds is used. If the alternatives are within a
-subpattern (defined below), "succeeds" means matching the rest of the main
-pattern as well as the alternative in the subpattern.
-
-
-.SH INTERNAL OPTION SETTING
-The settings of PCRE_CASELESS, PCRE_MULTILINE, PCRE_DOTALL, and PCRE_EXTENDED
-can be changed from within the pattern by a sequence of Perl option letters
-enclosed between "(?" and ")". The option letters are
-
-  i  for PCRE_CASELESS
-  m  for PCRE_MULTILINE
-  s  for PCRE_DOTALL
-  x  for PCRE_EXTENDED
-
-For example, (?im) sets caseless, multiline matching. It is also possible to
-unset these options by preceding the letter with a hyphen, and a combined
-setting and unsetting such as (?im-sx), which sets PCRE_CASELESS and
-PCRE_MULTILINE while unsetting PCRE_DOTALL and PCRE_EXTENDED, is also
-permitted. If a letter appears both before and after the hyphen, the option is
-unset.
-
-The scope of these option changes depends on where in the pattern the setting
-occurs. For settings that are outside any subpattern (defined below), the
-effect is the same as if the options were set or unset at the start of
-matching. The following patterns all behave in exactly the same way:
-
-  (?i)abc
-  a(?i)bc
-  ab(?i)c
-  abc(?i)
-
-which in turn is the same as compiling the pattern abc with PCRE_CASELESS set.
-In other words, such "top level" settings apply to the whole pattern (unless
-there are other changes inside subpatterns). If there is more than one setting
-of the same option at top level, the rightmost setting is used.
-
-If an option change occurs inside a subpattern, the effect is different. This
-is a change of behaviour in Perl 5.005. An option change inside a subpattern
-affects only that part of the subpattern that follows it, so
-
-  (a(?i)b)c
-
-matches abc and aBc and no other strings (assuming PCRE_CASELESS is not used).
-By this means, options can be made to have different settings in different
-parts of the pattern. Any changes made in one alternative do carry on
-into subsequent branches within the same subpattern. For example,
-
-  (a(?i)b|c)
-
-matches "ab", "aB", "c", and "C", even though when matching "C" the first
-branch is abandoned before the option setting. This is because the effects of
-option settings happen at compile time. There would be some very weird
-behaviour otherwise.
-
-The PCRE-specific options PCRE_UNGREEDY and PCRE_EXTRA can be changed in the
-same way as the Perl-compatible options by using the characters U and X
-respectively. The (?X) flag setting is special in that it must always occur
-earlier in the pattern than any of the additional features it turns on, even
-when it is at top level. It is best put at the start.
-
-
-.SH SUBPATTERNS
-Subpatterns are delimited by parentheses (round brackets), which can be nested.
-Marking part of a pattern as a subpattern does two things:
-
-1. It localizes a set of alternatives. For example, the pattern
-
-  cat(aract|erpillar|)
-
-matches one of the words "cat", "cataract", or "caterpillar". Without the
-parentheses, it would match "cataract", "erpillar" or the empty string.
-
-2. It sets up the subpattern as a capturing subpattern (as defined above).
-When the whole pattern matches, that portion of the subject string that matched
-the subpattern is passed back to the caller via the \fIovector\fR argument of
-\fBpcre_exec()\fR. Opening parentheses are counted from left to right (starting
-from 1) to obtain the numbers of the capturing subpatterns.
-
-For example, if the string "the red king" is matched against the pattern
-
-  the ((red|white) (king|queen))
-
-the captured substrings are "red king", "red", and "king", and are numbered 1,
-2, and 3.
-
-The fact that plain parentheses fulfil two functions is not always helpful.
-There are often times when a grouping subpattern is required without a
-capturing requirement. If an opening parenthesis is followed by "?:", the
-subpattern does not do any capturing, and is not counted when computing the
-number of any subsequent capturing subpatterns. For example, if the string "the
-white queen" is matched against the pattern
-
-  the ((?:red|white) (king|queen))
-
-the captured substrings are "white queen" and "queen", and are numbered 1 and
-2. The maximum number of captured substrings is 99, and the maximum number of
-all subpatterns, both capturing and non-capturing, is 200.
-
-As a convenient shorthand, if any option settings are required at the start of
-a non-capturing subpattern, the option letters may appear between the "?" and
-the ":". Thus the two patterns
-
-  (?i:saturday|sunday)
-  (?:(?i)saturday|sunday)
-
-match exactly the same set of strings. Because alternative branches are tried
-from left to right, and options are not reset until the end of the subpattern
-is reached, an option setting in one branch does affect subsequent branches, so
-the above patterns match "SUNDAY" as well as "Saturday".
-
-
-.SH REPETITION
-Repetition is specified by quantifiers, which can follow any of the following
-items:
-
-  a single character, possibly escaped
-  the . metacharacter
-  a character class
-  a back reference (see next section)
-  a parenthesized subpattern (unless it is an assertion - see below)
-
-The general repetition quantifier specifies a minimum and maximum number of
-permitted matches, by giving the two numbers in curly brackets (braces),
-separated by a comma. The numbers must be less than 65536, and the first must
-be less than or equal to the second. For example:
-
-  z{2,4}
-
-matches "zz", "zzz", or "zzzz". A closing brace on its own is not a special
-character. If the second number is omitted, but the comma is present, there is
-no upper limit; if the second number and the comma are both omitted, the
-quantifier specifies an exact number of required matches. Thus
-
-  [aeiou]{3,}
-
-matches at least 3 successive vowels, but may match many more, while
-
-  \\d{8}
-
-matches exactly 8 digits. An opening curly bracket that appears in a position
-where a quantifier is not allowed, or one that does not match the syntax of a
-quantifier, is taken as a literal character. For example, {,6} is not a
-quantifier, but a literal string of four characters.
-
-The quantifier {0} is permitted, causing the expression to behave as if the
-previous item and the quantifier were not present.
-
-For convenience (and historical compatibility) the three most common
-quantifiers have single-character abbreviations:
-
-  *    is equivalent to {0,}
-  +    is equivalent to {1,}
-  ?    is equivalent to {0,1}
-
-It is possible to construct infinite loops by following a subpattern that can
-match no characters with a quantifier that has no upper limit, for example:
-
-  (a?)*
-
-Earlier versions of Perl and PCRE used to give an error at compile time for
-such patterns. However, because there are cases where this can be useful, such
-patterns are now accepted, but if any repetition of the subpattern does in fact
-match no characters, the loop is forcibly broken.
-
-By default, the quantifiers are "greedy", that is, they match as much as
-possible (up to the maximum number of permitted times), without causing the
-rest of the pattern to fail. The classic example of where this gives problems
-is in trying to match comments in C programs. These appear between the
-sequences /* and */ and within the sequence, individual * and / characters may
-appear. An attempt to match C comments by applying the pattern
-
-  /\\*.*\\*/
-
-to the string
-
-  /* first command */  not comment  /* second comment */
-
-fails, because it matches the entire string owing to the greediness of the .*
-item.
-
-However, if a quantifier is followed by a question mark, it ceases to be
-greedy, and instead matches the minimum number of times possible, so the
-pattern
-
-  /\\*.*?\\*/
-
-does the right thing with the C comments. The meaning of the various
-quantifiers is not otherwise changed, just the preferred number of matches.
-Do not confuse this use of question mark with its use as a quantifier in its
-own right. Because it has two uses, it can sometimes appear doubled, as in
-
-  \\d??\\d
-
-which matches one digit by preference, but can match two if that is the only
-way the rest of the pattern matches.
-
-If the PCRE_UNGREEDY option is set (an option which is not available in Perl),
-the quantifiers are not greedy by default, but individual ones can be made
-greedy by following them with a question mark. In other words, it inverts the
-default behaviour.
-
-When a parenthesized subpattern is quantified with a minimum repeat count that
-is greater than 1 or with a limited maximum, more store is required for the
-compiled pattern, in proportion to the size of the minimum or maximum.
-
-If a pattern starts with .* or .{0,} and the PCRE_DOTALL option (equivalent
-to Perl's /s) is set, thus allowing the . to match newlines, the pattern is
-implicitly anchored, because whatever follows will be tried against every
-character position in the subject string, so there is no point in retrying the
-overall match at any position after the first. PCRE treats such a pattern as
-though it were preceded by \\A. In cases where it is known that the subject
-string contains no newlines, it is worth setting PCRE_DOTALL when the pattern
-begins with .* in order to obtain this optimization, or alternatively using ^
-to indicate anchoring explicitly.
-
-When a capturing subpattern is repeated, the value captured is the substring
-that matched the final iteration. For example, after
-
-  (tweedle[dume]{3}\\s*)+
-
-has matched "tweedledum tweedledee" the value of the captured substring is
-"tweedledee". However, if there are nested capturing subpatterns, the
-corresponding captured values may have been set in previous iterations. For
-example, after
-
-  /(a|(b))+/
-
-matches "aba" the value of the second captured substring is "b".
-
-
-.SH BACK REFERENCES
-Outside a character class, a backslash followed by a digit greater than 0 (and
-possibly further digits) is a back reference to a capturing subpattern earlier
-(i.e. to its left) in the pattern, provided there have been that many previous
-capturing left parentheses.
-
-However, if the decimal number following the backslash is less than 10, it is
-always taken as a back reference, and causes an error only if there are not
-that many capturing left parentheses in the entire pattern. In other words, the
-parentheses that are referenced need not be to the left of the reference for
-numbers less than 10. See the section entitled "Backslash" above for further
-details of the handling of digits following a backslash.
-
-A back reference matches whatever actually matched the capturing subpattern in
-the current subject string, rather than anything matching the subpattern
-itself. So the pattern
-
-  (sens|respons)e and \\1ibility
-
-matches "sense and sensibility" and "response and responsibility", but not
-"sense and responsibility". If caseful matching is in force at the time of the
-back reference, the case of letters is relevant. For example,
-
-  ((?i)rah)\\s+\\1
-
-matches "rah rah" and "RAH RAH", but not "RAH rah", even though the original
-capturing subpattern is matched caselessly.
-
-There may be more than one back reference to the same subpattern. If a
-subpattern has not actually been used in a particular match, any back
-references to it always fail. For example, the pattern
-
-  (a|(bc))\\2
-
-always fails if it starts to match "a" rather than "bc". Because there may be
-up to 99 back references, all digits following the backslash are taken
-as part of a potential back reference number. If the pattern continues with a
-digit character, some delimiter must be used to terminate the back reference.
-If the PCRE_EXTENDED option is set, this can be whitespace. Otherwise an empty
-comment can be used.
-
-A back reference that occurs inside the parentheses to which it refers fails
-when the subpattern is first used, so, for example, (a\\1) never matches.
-However, such references can be useful inside repeated subpatterns. For
-example, the pattern
-
-  (a|b\\1)+
-
-matches any number of "a"s and also "aba", "ababbaa" etc. At each iteration of
-the subpattern, the back reference matches the character string corresponding
-to the previous iteration. In order for this to work, the pattern must be such
-that the first iteration does not need to match the back reference. This can be
-done using alternation, as in the example above, or by a quantifier with a
-minimum of zero.
-
-
-.SH ASSERTIONS
-An assertion is a test on the characters following or preceding the current
-matching point that does not actually consume any characters. The simple
-assertions coded as \\b, \\B, \\A, \\Z, \\z, ^ and $ are described above. More
-complicated assertions are coded as subpatterns. There are two kinds: those
-that look ahead of the current position in the subject string, and those that
-look behind it.
-
-An assertion subpattern is matched in the normal way, except that it does not
-cause the current matching position to be changed. Lookahead assertions start
-with (?= for positive assertions and (?! for negative assertions. For example,
-
-  \\w+(?=;)
-
-matches a word followed by a semicolon, but does not include the semicolon in
-the match, and
-
-  foo(?!bar)
-
-matches any occurrence of "foo" that is not followed by "bar". Note that the
-apparently similar pattern
-
-  (?!foo)bar
-
-does not find an occurrence of "bar" that is preceded by something other than
-"foo"; it finds any occurrence of "bar" whatsoever, because the assertion
-(?!foo) is always true when the next three characters are "bar". A
-lookbehind assertion is needed to achieve this effect.
-
-Lookbehind assertions start with (?<= for positive assertions and (?<! for
-negative assertions. For example,
-
-  (?<!foo)bar
-
-does find an occurrence of "bar" that is not preceded by "foo". The contents of
-a lookbehind assertion are restricted such that all the strings it matches must
-have a fixed length. However, if there are several alternatives, they do not
-all have to have the same fixed length. Thus
-
-  (?<=bullock|donkey)
-
-is permitted, but
-
-  (?<!dogs?|cats?)
-
-causes an error at compile time. Branches that match different length strings
-are permitted only at the top level of a lookbehind assertion. This is an
-extension compared with Perl 5.005, which requires all branches to match the
-same length of string. An assertion such as
-
-  (?<=ab(c|de))
-
-is not permitted, because its single top-level branch can match two different
-lengths, but it is acceptable if rewritten to use two top-level branches:
-
-  (?<=abc|abde)
-
-The implementation of lookbehind assertions is, for each alternative, to
-temporarily move the current position back by the fixed width and then try to
-match. If there are insufficient characters before the current position, the
-match is deemed to fail. Lookbehinds in conjunction with once-only subpatterns
-can be particularly useful for matching at the ends of strings; an example is
-given at the end of the section on once-only subpatterns.
-
-Several assertions (of any sort) may occur in succession. For example,
-
-  (?<=\\d{3})(?<!999)foo
-
-matches "foo" preceded by three digits that are not "999". Notice that each of
-the assertions is applied independently at the same point in the subject
-string. First there is a check that the previous three characters are all
-digits, and then there is a check that the same three characters are not "999".
-This pattern does \fInot\fR match "foo" preceded by six characters, the first
-of which are digits and the last three of which are not "999". For example, it
-doesn't match "123abcfoo". A pattern to do that is
-
-  (?<=\\d{3}...)(?<!999)foo
-
-This time the first assertion looks at the preceding six characters, checking
-that the first three are digits, and then the second assertion checks that the
-preceding three characters are not "999".
-
-Assertions can be nested in any combination. For example,
-
-  (?<=(?<!foo)bar)baz
-
-matches an occurrence of "baz" that is preceded by "bar" which in turn is not
-preceded by "foo", while
-
-  (?<=\\d{3}(?!999)...)foo
-
-is another pattern which matches "foo" preceded by three digits and any three
-characters that are not "999".
-
-Assertion subpatterns are not capturing subpatterns, and may not be repeated,
-because it makes no sense to assert the same thing several times. If any kind
-of assertion contains capturing subpatterns within it, these are counted for
-the purposes of numbering the capturing subpatterns in the whole pattern.
-However, substring capturing is carried out only for positive assertions,
-because it does not make sense for negative assertions.
-
-Assertions count towards the maximum of 200 parenthesized subpatterns.
-
-
-.SH ONCE-ONLY SUBPATTERNS
-With both maximizing and minimizing repetition, failure of what follows
-normally causes the repeated item to be re-evaluated to see if a different
-number of repeats allows the rest of the pattern to match. Sometimes it is
-useful to prevent this, either to change the nature of the match, or to cause
-it fail earlier than it otherwise might, when the author of the pattern knows
-there is no point in carrying on.
-
-Consider, for example, the pattern \\d+foo when applied to the subject line
-
-  123456bar
-
-After matching all 6 digits and then failing to match "foo", the normal
-action of the matcher is to try again with only 5 digits matching the \\d+
-item, and then with 4, and so on, before ultimately failing. Once-only
-subpatterns provide the means for specifying that once a portion of the pattern
-has matched, it is not to be re-evaluated in this way, so the matcher would
-give up immediately on failing to match "foo" the first time. The notation is
-another kind of special parenthesis, starting with (?> as in this example:
-
-  (?>\\d+)bar
-
-This kind of parenthesis "locks up" the  part of the pattern it contains once
-it has matched, and a failure further into the pattern is prevented from
-backtracking into it. Backtracking past it to previous items, however, works as
-normal.
-
-An alternative description is that a subpattern of this type matches the string
-of characters that an identical standalone pattern would match, if anchored at
-the current point in the subject string.
-
-Once-only subpatterns are not capturing subpatterns. Simple cases such as the
-above example can be thought of as a maximizing repeat that must swallow
-everything it can. So, while both \\d+ and \\d+? are prepared to adjust the
-number of digits they match in order to make the rest of the pattern match,
-(?>\\d+) can only match an entire sequence of digits.
-
-This construction can of course contain arbitrarily complicated subpatterns,
-and it can be nested.
-
-Once-only subpatterns can be used in conjunction with lookbehind assertions to
-specify efficient matching at the end of the subject string. Consider a simple
-pattern such as
-
-  abcd$
-
-when applied to a long string which does not match. Because matching proceeds
-from left to right, PCRE will look for each "a" in the subject and then see if
-what follows matches the rest of the pattern. If the pattern is specified as
-
-  ^.*abcd$
-
-the initial .* matches the entire string at first, but when this fails (because
-there is no following "a"), it backtracks to match all but the last character,
-then all but the last two characters, and so on. Once again the search for "a"
-covers the entire string, from right to left, so we are no better off. However,
-if the pattern is written as
-
-  ^(?>.*)(?<=abcd)
-
-there can be no backtracking for the .* item; it can match only the entire
-string. The subsequent lookbehind assertion does a single test on the last four
-characters. If it fails, the match fails immediately. For long strings, this
-approach makes a significant difference to the processing time.
-
-When a pattern contains an unlimited repeat inside a subpattern that can itself
-be repeated an unlimited number of times, the use of a once-only subpattern is
-the only way to avoid some failing matches taking a very long time indeed.
-The pattern
-
-  (\\D+|<\\d+>)*[!?]
-
-matches an unlimited number of substrings that either consist of non-digits, or
-digits enclosed in <>, followed by either ! or ?. When it matches, it runs
-quickly. However, if it is applied to
-
-  aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
-
-it takes a long time before reporting failure. This is because the string can
-be divided between the two repeats in a large number of ways, and all have to
-be tried. (The example used [!?] rather than a single character at the end,
-because both PCRE and Perl have an optimization that allows for fast failure
-when a single character is used. They remember the last single character that
-is required for a match, and fail early if it is not present in the string.)
-If the pattern is changed to
-
-  ((?>\\D+)|<\\d+>)*[!?]
-
-sequences of non-digits cannot be broken, and failure happens quickly.
-
-
-.SH CONDITIONAL SUBPATTERNS
-It is possible to cause the matching process to obey a subpattern
-conditionally or to choose between two alternative subpatterns, depending on
-the result of an assertion, or whether a previous capturing subpattern matched
-or not. The two possible forms of conditional subpattern are
-
-  (?(condition)yes-pattern)
-  (?(condition)yes-pattern|no-pattern)
-
-If the condition is satisfied, the yes-pattern is used; otherwise the
-no-pattern (if present) is used. If there are more than two alternatives in the
-subpattern, a compile-time error occurs.
-
-There are two kinds of condition. If the text between the parentheses consists
-of a sequence of digits, the condition is satisfied if the capturing subpattern
-of that number has previously matched. The number must be greater than zero.
-Consider the following pattern, which contains non-significant white space to
-make it more readable (assume the PCRE_EXTENDED option) and to divide it into
-three parts for ease of discussion:
-
-  ( \\( )?    [^()]+    (?(1) \\) )
-
-The first part matches an optional opening parenthesis, and if that
-character is present, sets it as the first captured substring. The second part
-matches one or more characters that are not parentheses. The third part is a
-conditional subpattern that tests whether the first set of parentheses matched
-or not. If they did, that is, if subject started with an opening parenthesis,
-the condition is true, and so the yes-pattern is executed and a closing
-parenthesis is required. Otherwise, since no-pattern is not present, the
-subpattern matches nothing. In other words, this pattern matches a sequence of
-non-parentheses, optionally enclosed in parentheses.
-
-If the condition is not a sequence of digits, it must be an assertion. This may
-be a positive or negative lookahead or lookbehind assertion. Consider this
-pattern, again containing non-significant white space, and with the two
-alternatives on the second line:
-
-  (?(?=[^a-z]*[a-z])
-  \\d{2}-[a-z]{3}-\\d{2}  |  \\d{2}-\\d{2}-\\d{2} )
-
-The condition is a positive lookahead assertion that matches an optional
-sequence of non-letters followed by a letter. In other words, it tests for the
-presence of at least one letter in the subject. If a letter is found, the
-subject is matched against the first alternative; otherwise it is matched
-against the second. This pattern matches strings in one of the two forms
-dd-aaa-dd or dd-dd-dd, where aaa are letters and dd are digits.
-
-
-.SH COMMENTS
-The sequence (?# marks the start of a comment which continues up to the next
-closing parenthesis. Nested parentheses are not permitted. The characters
-that make up a comment play no part in the pattern matching at all.
-
-If the PCRE_EXTENDED option is set, an unescaped # character outside a
-character class introduces a comment that continues up to the next newline
-character in the pattern.
-
-
-.SH RECURSIVE PATTERNS
-Consider the problem of matching a string in parentheses, allowing for
-unlimited nested parentheses. Without the use of recursion, the best that can
-be done is to use a pattern that matches up to some fixed depth of nesting. It
-is not possible to handle an arbitrary nesting depth. Perl 5.6 has provided an
-experimental facility that allows regular expressions to recurse (amongst other
-things). It does this by interpolating Perl code in the expression at run time,
-and the code can refer to the expression itself. A Perl pattern to solve the
-parentheses problem can be created like this:
-
-  $re = qr{\\( (?: (?>[^()]+) | (?p{$re}) )* \\)}x;
-
-The (?p{...}) item interpolates Perl code at run time, and in this case refers
-recursively to the pattern in which it appears. Obviously, PCRE cannot support
-the interpolation of Perl code. Instead, the special item (?R) is provided for
-the specific case of recursion. This PCRE pattern solves the parentheses
-problem (assume the PCRE_EXTENDED option is set so that white space is
-ignored):
-
-  \\( ( (?>[^()]+) | (?R) )* \\)
-
-First it matches an opening parenthesis. Then it matches any number of
-substrings which can either be a sequence of non-parentheses, or a recursive
-match of the pattern itself (i.e. a correctly parenthesized substring). Finally
-there is a closing parenthesis.
-
-This particular example pattern contains nested unlimited repeats, and so the
-use of a once-only subpattern for matching strings of non-parentheses is
-important when applying the pattern to strings that do not match. For example,
-when it is applied to
-
-  (aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa()
-
-it yields "no match" quickly. However, if a once-only subpattern is not used,
-the match runs for a very long time indeed because there are so many different
-ways the + and * repeats can carve up the subject, and all have to be tested
-before failure can be reported.
-
-The values set for any capturing subpatterns are those from the outermost level
-of the recursion at which the subpattern value is set. If the pattern above is
-matched against
-
-  (ab(cd)ef)
-
-the value for the capturing parentheses is "ef", which is the last value taken
-on at the top level. If additional parentheses are added, giving
-
-  \\( ( ( (?>[^()]+) | (?R) )* ) \\)
-     ^                        ^
-     ^                        ^
-the string they capture is "ab(cd)ef", the contents of the top level
-parentheses. If there are more than 15 capturing parentheses in a pattern, PCRE
-has to obtain extra memory to store data during a recursion, which it does by
-using \fBpcre_malloc\fR, freeing it via \fBpcre_free\fR afterwards. If no
-memory can be obtained, it saves data for the first 15 capturing parentheses
-only, as there is no way to give an out-of-memory error from within a
-recursion.
-
-
-.SH PERFORMANCE
-Certain items that may appear in patterns are more efficient than others. It is
-more efficient to use a character class like [aeiou] than a set of alternatives
-such as (a|e|i|o|u). In general, the simplest construction that provides the
-required behaviour is usually the most efficient. Jeffrey Friedl's book
-contains a lot of discussion about optimizing regular expressions for efficient
-performance.
-
-When a pattern begins with .* and the PCRE_DOTALL option is set, the pattern is
-implicitly anchored by PCRE, since it can match only at the start of a subject
-string. However, if PCRE_DOTALL is not set, PCRE cannot make this optimization,
-because the . metacharacter does not then match a newline, and if the subject
-string contains newlines, the pattern may match from the character immediately
-following one of them instead of from the very start. For example, the pattern
-
-  (.*) second
-
-matches the subject "first\\nand second" (where \\n stands for a newline
-character) with the first captured substring being "and". In order to do this,
-PCRE has to retry the match starting after every newline in the subject.
-
-If you are using such a pattern with subject strings that do not contain
-newlines, the best performance is obtained by setting PCRE_DOTALL, or starting
-the pattern with ^.* to indicate explicit anchoring. That saves PCRE from
-having to scan along the subject looking for a newline to restart at.
-
-Beware of patterns that contain nested indefinite repeats. These can take a
-long time to run when applied to a string that does not match. Consider the
-pattern fragment
-
-  (a+)*
-
-This can match "aaaa" in 33 different ways, and this number increases very
-rapidly as the string gets longer. (The * repeat can match 0, 1, 2, 3, or 4
-times, and for each of those cases other than 0, the + repeats can match
-different numbers of times.) When the remainder of the pattern is such that the
-entire match is going to fail, PCRE has in principle to try every possible
-variation, and this can take an extremely long time.
-
-An optimization catches some of the more simple cases such as
-
-  (a+)*b
-
-where a literal character follows. Before embarking on the standard matching
-procedure, PCRE checks that there is a "b" later in the subject string, and if
-there is not, it fails the match immediately. However, when there is no
-following literal this optimization cannot be used. You can see the difference
-by comparing the behaviour of
-
-  (a+)*\\d
-
-with the pattern above. The former gives a failure almost instantly when
-applied to a whole line of "a" characters, whereas the latter takes an
-appreciable time with strings longer than about 20 characters.
-
-
-.SH UTF-8 SUPPORT
-Starting at release 3.3, PCRE has some support for character strings encoded
-in the UTF-8 format. This is incomplete, and is regarded as experimental. In
-order to use it, you must configure PCRE to include UTF-8 support in the code,
-and, in addition, you must call \fBpcre_compile()\fR with the PCRE_UTF8 option
-flag. When you do this, both the pattern and any subject strings that are
-matched against it are treated as UTF-8 strings instead of just strings of
-bytes, but only in the cases that are mentioned below.
-
-If you compile PCRE with UTF-8 support, but do not use it at run time, the
-library will be a bit bigger, but the additional run time overhead is limited
-to testing the PCRE_UTF8 flag in several places, so should not be very large.
-
-PCRE assumes that the strings it is given contain valid UTF-8 codes. It does
-not diagnose invalid UTF-8 strings. If you pass invalid UTF-8 strings to PCRE,
-the results are undefined.
-
-Running with PCRE_UTF8 set causes these changes in the way PCRE works:
-
-1. In a pattern, the escape sequence \\x{...}, where the contents of the braces
-is a string of hexadecimal digits, is interpreted as a UTF-8 character whose
-code number is the given hexadecimal number, for example: \\x{1234}. This
-inserts from one to six literal bytes into the pattern, using the UTF-8
-encoding. If a non-hexadecimal digit appears between the braces, the item is
-not recognized.
-
-2. The original hexadecimal escape sequence, \\xhh, generates a two-byte UTF-8
-character if its value is greater than 127.
-
-3. Repeat quantifiers are NOT correctly handled if they follow a multibyte
-character. For example, \\x{100}* and \\xc3+ do not work. If you want to
-repeat such characters, you must enclose them in non-capturing parentheses,
-for example (?:\\x{100}), at present.
-
-4. The dot metacharacter matches one UTF-8 character instead of a single byte.
-
-5. Unlike literal UTF-8 characters, the dot metacharacter followed by a
-repeat quantifier does operate correctly on UTF-8 characters instead of
-single bytes.
-
-4. Although the \\x{...} escape is permitted in a character class, characters
-whose values are greater than 255 cannot be included in a class.
-
-5. A class is matched against a UTF-8 character instead of just a single byte,
-but it can match only characters whose values are less than 256. Characters
-with greater values always fail to match a class.
-
-6. Repeated classes work correctly on multiple characters.
-
-7. Classes containing just a single character whose value is greater than 127
-(but less than 256), for example, [\\x80] or [^\\x{93}], do not work because
-these are optimized into single byte matches. In the first case, of course,
-the class brackets are just redundant.
-
-8. Lookbehind assertions move backwards in the subject by a fixed number of
-characters instead of a fixed number of bytes. Simple cases have been tested
-to work correctly, but there may be hidden gotchas herein.
-
-9. The character types such as \\d and \\w do not work correctly with UTF-8
-characters. They continue to test a single byte.
-
-10. Anything not explicitly mentioned here continues to work in bytes rather
-than in characters.
-
-The following UTF-8 features of Perl 5.6 are not implemented:
-
-1. The escape sequence \\C to match a single byte.
-
-2. The use of Unicode tables and properties and escapes \\p, \\P, and \\X.
-
-.SH AUTHOR
-Philip Hazel <ph10@cam.ac.uk>
-.br
-University Computing Service,
-.br
-New Museums Site,
-.br
-Cambridge CB2 3QG, England.
-.br
-Phone: +44 1223 334714
-
-Last updated: 28 August 2000,
-.br
-  the 250th anniversary of the death of J.S. Bach.
-.br
-Copyright (c) 1997-2000 University of Cambridge.
diff --git a/ext/pcre/pcrelib/doc/pcre.html b/ext/pcre/pcrelib/doc/pcre.html
deleted file mode 100644
index 01770975e2..0000000000
--- a/ext/pcre/pcrelib/doc/pcre.html
+++ /dev/null
@@ -1,2397 +0,0 @@
-<HTML>
-<HEAD>
-<TITLE>pcre specification</TITLE>
-</HEAD>
-<body bgcolor="#FFFFFF" text="#00005A">
-<H1>pcre specification</H1>
-This HTML document has been generated automatically from the original man page.
-If there is any nonsense in it, please consult the man page in case the
-conversion went wrong.
-<UL>
-<LI><A NAME="TOC1" HREF="#SEC1">NAME</A>
-<LI><A NAME="TOC2" HREF="#SEC2">SYNOPSIS</A>
-<LI><A NAME="TOC3" HREF="#SEC3">DESCRIPTION</A>
-<LI><A NAME="TOC4" HREF="#SEC4">MULTI-THREADING</A>
-<LI><A NAME="TOC5" HREF="#SEC5">COMPILING A PATTERN</A>
-<LI><A NAME="TOC6" HREF="#SEC6">STUDYING A PATTERN</A>
-<LI><A NAME="TOC7" HREF="#SEC7">LOCALE SUPPORT</A>
-<LI><A NAME="TOC8" HREF="#SEC8">INFORMATION ABOUT A PATTERN</A>
-<LI><A NAME="TOC9" HREF="#SEC9">MATCHING A PATTERN</A>
-<LI><A NAME="TOC10" HREF="#SEC10">EXTRACTING CAPTURED SUBSTRINGS</A>
-<LI><A NAME="TOC11" HREF="#SEC11">LIMITATIONS</A>
-<LI><A NAME="TOC12" HREF="#SEC12">DIFFERENCES FROM PERL</A>
-<LI><A NAME="TOC13" HREF="#SEC13">REGULAR EXPRESSION DETAILS</A>
-<LI><A NAME="TOC14" HREF="#SEC14">BACKSLASH</A>
-<LI><A NAME="TOC15" HREF="#SEC15">CIRCUMFLEX AND DOLLAR</A>
-<LI><A NAME="TOC16" HREF="#SEC16">FULL STOP (PERIOD, DOT)</A>
-<LI><A NAME="TOC17" HREF="#SEC17">SQUARE BRACKETS</A>
-<LI><A NAME="TOC18" HREF="#SEC18">POSIX CHARACTER CLASSES</A>
-<LI><A NAME="TOC19" HREF="#SEC19">VERTICAL BAR</A>
-<LI><A NAME="TOC20" HREF="#SEC20">INTERNAL OPTION SETTING</A>
-<LI><A NAME="TOC21" HREF="#SEC21">SUBPATTERNS</A>
-<LI><A NAME="TOC22" HREF="#SEC22">REPETITION</A>
-<LI><A NAME="TOC23" HREF="#SEC23">BACK REFERENCES</A>
-<LI><A NAME="TOC24" HREF="#SEC24">ASSERTIONS</A>
-<LI><A NAME="TOC25" HREF="#SEC25">ONCE-ONLY SUBPATTERNS</A>
-<LI><A NAME="TOC26" HREF="#SEC26">CONDITIONAL SUBPATTERNS</A>
-<LI><A NAME="TOC27" HREF="#SEC27">COMMENTS</A>
-<LI><A NAME="TOC28" HREF="#SEC28">RECURSIVE PATTERNS</A>
-<LI><A NAME="TOC29" HREF="#SEC29">PERFORMANCE</A>
-<LI><A NAME="TOC30" HREF="#SEC30">UTF-8 SUPPORT</A>
-<LI><A NAME="TOC31" HREF="#SEC31">AUTHOR</A>
-</UL>
-<LI><A NAME="SEC1" HREF="#TOC1">NAME</A>
-<P>
-pcre - Perl-compatible regular expressions.
-</P>
-<LI><A NAME="SEC2" HREF="#TOC1">SYNOPSIS</A>
-<P>
-<B>#include &#60;pcre.h&#62;</B>
-</P>
-<P>
-<B>pcre *pcre_compile(const char *<I>pattern</I>, int <I>options</I>,</B>
-<B>const char **<I>errptr</I>, int *<I>erroffset</I>,</B>
-<B>const unsigned char *<I>tableptr</I>);</B>
-</P>
-<P>
-<B>pcre_extra *pcre_study(const pcre *<I>code</I>, int <I>options</I>,</B>
-<B>const char **<I>errptr</I>);</B>
-</P>
-<P>
-<B>int pcre_exec(const pcre *<I>code</I>, const pcre_extra *<I>extra</I>,</B>
-<B>const char *<I>subject</I>, int <I>length</I>, int <I>startoffset</I>,</B>
-<B>int <I>options</I>, int *<I>ovector</I>, int <I>ovecsize</I>);</B>
-</P>
-<P>
-<B>int pcre_copy_substring(const char *<I>subject</I>, int *<I>ovector</I>,</B>
-<B>int <I>stringcount</I>, int <I>stringnumber</I>, char *<I>buffer</I>,</B>
-<B>int <I>buffersize</I>);</B>
-</P>
-<P>
-<B>int pcre_get_substring(const char *<I>subject</I>, int *<I>ovector</I>,</B>
-<B>int <I>stringcount</I>, int <I>stringnumber</I>,</B>
-<B>const char **<I>stringptr</I>);</B>
-</P>
-<P>
-<B>int pcre_get_substring_list(const char *<I>subject</I>,</B>
-<B>int *<I>ovector</I>, int <I>stringcount</I>, const char ***<I>listptr</I>);</B>
-</P>
-<P>
-<B>void pcre_free_substring(const char *<I>stringptr</I>);</B>
-</P>
-<P>
-<B>void pcre_free_substring_list(const char **<I>stringptr</I>);</B>
-</P>
-<P>
-<B>const unsigned char *pcre_maketables(void);</B>
-</P>
-<P>
-<B>int pcre_fullinfo(const pcre *<I>code</I>, const pcre_extra *<I>extra</I>,</B>
-<B>int <I>what</I>, void *<I>where</I>);</B>
-</P>
-<P>
-<B>int pcre_info(const pcre *<I>code</I>, int *<I>optptr</I>, int</B>
-<B>*<I>firstcharptr</I>);</B>
-</P>
-<P>
-<B>char *pcre_version(void);</B>
-</P>
-<P>
-<B>void *(*pcre_malloc)(size_t);</B>
-</P>
-<P>
-<B>void (*pcre_free)(void *);</B>
-</P>
-<LI><A NAME="SEC3" HREF="#TOC1">DESCRIPTION</A>
-<P>
-The PCRE library is a set of functions that implement regular expression
-pattern matching using the same syntax and semantics as Perl 5, with just a few
-differences (see below). The current implementation corresponds to Perl 5.005,
-with some additional features from later versions. This includes some
-experimental, incomplete support for UTF-8 encoded strings. Details of exactly
-what is and what is not supported are given below.
-</P>
-<P>
-PCRE has its own native API, which is described in this document. There is also
-a set of wrapper functions that correspond to the POSIX regular expression API.
-These are described in the <B>pcreposix</B> documentation.
-</P>
-<P>
-The native API function prototypes are defined in the header file <B>pcre.h</B>,
-and on Unix systems the library itself is called <B>libpcre.a</B>, so can be
-accessed by adding <B>-lpcre</B> to the command for linking an application which
-calls it. The header file defines the macros PCRE_MAJOR and PCRE_MINOR to
-contain the major and minor release numbers for the library. Applications can
-use these to include support for different releases.
-</P>
-<P>
-The functions <B>pcre_compile()</B>, <B>pcre_study()</B>, and <B>pcre_exec()</B>
-are used for compiling and matching regular expressions.
-</P>
-<P>
-The functions <B>pcre_copy_substring()</B>, <B>pcre_get_substring()</B>, and
-<B>pcre_get_substring_list()</B> are convenience functions for extracting
-captured substrings from a matched subject string; <B>pcre_free_substring()</B>
-and <B>pcre_free_substring_list()</B> are also provided, to free the memory used
-for extracted strings.
-</P>
-<P>
-The function <B>pcre_maketables()</B> is used (optionally) to build a set of
-character tables in the current locale for passing to <B>pcre_compile()</B>.
-</P>
-<P>
-The function <B>pcre_fullinfo()</B> is used to find out information about a
-compiled pattern; <B>pcre_info()</B> is an obsolete version which returns only
-some of the available information, but is retained for backwards compatibility.
-The function <B>pcre_version()</B> returns a pointer to a string containing the
-version of PCRE and its date of release.
-</P>
-<P>
-The global variables <B>pcre_malloc</B> and <B>pcre_free</B> initially contain
-the entry points of the standard <B>malloc()</B> and <B>free()</B> functions
-respectively. PCRE calls the memory management functions via these variables,
-so a calling program can replace them if it wishes to intercept the calls. This
-should be done before calling any PCRE functions.
-</P>
-<LI><A NAME="SEC4" HREF="#TOC1">MULTI-THREADING</A>
-<P>
-The PCRE functions can be used in multi-threading applications, with the
-proviso that the memory management functions pointed to by <B>pcre_malloc</B>
-and <B>pcre_free</B> are shared by all threads.
-</P>
-<P>
-The compiled form of a regular expression is not altered during matching, so
-the same compiled pattern can safely be used by several threads at once.
-</P>
-<LI><A NAME="SEC5" HREF="#TOC1">COMPILING A PATTERN</A>
-<P>
-The function <B>pcre_compile()</B> is called to compile a pattern into an
-internal form. The pattern is a C string terminated by a binary zero, and
-is passed in the argument <I>pattern</I>. A pointer to a single block of memory
-that is obtained via <B>pcre_malloc</B> is returned. This contains the
-compiled code and related data. The <B>pcre</B> type is defined for this for
-convenience, but in fact <B>pcre</B> is just a typedef for <B>void</B>, since the
-contents of the block are not externally defined. It is up to the caller to
-free the memory when it is no longer required.
-</P>
-<P>
-The size of a compiled pattern is roughly proportional to the length of the
-pattern string, except that each character class (other than those containing
-just a single character, negated or not) requires 33 bytes, and repeat
-quantifiers with a minimum greater than one or a bounded maximum cause the
-relevant portions of the compiled pattern to be replicated.
-</P>
-<P>
-The <I>options</I> argument contains independent bits that affect the
-compilation. It should be zero if no options are required. Some of the options,
-in particular, those that are compatible with Perl, can also be set and unset
-from within the pattern (see the detailed description of regular expressions
-below). For these options, the contents of the <I>options</I> argument specifies
-their initial settings at the start of compilation and execution. The
-PCRE_ANCHORED option can be set at the time of matching as well as at compile
-time.
-</P>
-<P>
-If <I>errptr</I> is NULL, <B>pcre_compile()</B> returns NULL immediately.
-Otherwise, if compilation of a pattern fails, <B>pcre_compile()</B> returns
-NULL, and sets the variable pointed to by <I>errptr</I> to point to a textual
-error message. The offset from the start of the pattern to the character where
-the error was discovered is placed in the variable pointed to by
-<I>erroffset</I>, which must not be NULL. If it is, an immediate error is given.
-</P>
-<P>
-If the final argument, <I>tableptr</I>, is NULL, PCRE uses a default set of
-character tables which are built when it is compiled, using the default C
-locale. Otherwise, <I>tableptr</I> must be the result of a call to
-<B>pcre_maketables()</B>. See the section on locale support below.
-</P>
-<P>
-The following option bits are defined in the header file:
-</P>
-<P>
-<PRE>
-  PCRE_ANCHORED
-</PRE>
-</P>
-<P>
-If this bit is set, the pattern is forced to be "anchored", that is, it is
-constrained to match only at the start of the string which is being searched
-(the "subject string"). This effect can also be achieved by appropriate
-constructs in the pattern itself, which is the only way to do it in Perl.
-</P>
-<P>
-<PRE>
-  PCRE_CASELESS
-</PRE>
-</P>
-<P>
-If this bit is set, letters in the pattern match both upper and lower case
-letters. It is equivalent to Perl's /i option.
-</P>
-<P>
-<PRE>
-  PCRE_DOLLAR_ENDONLY
-</PRE>
-</P>
-<P>
-If this bit is set, a dollar metacharacter in the pattern matches only at the
-end of the subject string. Without this option, a dollar also matches
-immediately before the final character if it is a newline (but not before any
-other newlines). The PCRE_DOLLAR_ENDONLY option is ignored if PCRE_MULTILINE is
-set. There is no equivalent to this option in Perl.
-</P>
-<P>
-<PRE>
-  PCRE_DOTALL
-</PRE>
-</P>
-<P>
-If this bit is set, a dot metacharater in the pattern matches all characters,
-including newlines. Without it, newlines are excluded. This option is
-equivalent to Perl's /s option. A negative class such as [^a] always matches a
-newline character, independent of the setting of this option.
-</P>
-<P>
-<PRE>
-  PCRE_EXTENDED
-</PRE>
-</P>
-<P>
-If this bit is set, whitespace data characters in the pattern are totally
-ignored except when escaped or inside a character class, and characters between
-an unescaped # outside a character class and the next newline character,
-inclusive, are also ignored. This is equivalent to Perl's /x option, and makes
-it possible to include comments inside complicated patterns. Note, however,
-that this applies only to data characters. Whitespace characters may never
-appear within special character sequences in a pattern, for example within the
-sequence (?( which introduces a conditional subpattern.
-</P>
-<P>
-<PRE>
-  PCRE_EXTRA
-</PRE>
-</P>
-<P>
-This option was invented in order to turn on additional functionality of PCRE
-that is incompatible with Perl, but it is currently of very little use. When
-set, any backslash in a pattern that is followed by a letter that has no
-special meaning causes an error, thus reserving these combinations for future
-expansion. By default, as in Perl, a backslash followed by a letter with no
-special meaning is treated as a literal. There are at present no other features
-controlled by this option. It can also be set by a (?X) option setting within a
-pattern.
-</P>
-<P>
-<PRE>
-  PCRE_MULTILINE
-</PRE>
-</P>
-<P>
-By default, PCRE treats the subject string as consisting of a single "line" of
-characters (even if it actually contains several newlines). The "start of line"
-metacharacter (^) matches only at the start of the string, while the "end of
-line" metacharacter ($) matches only at the end of the string, or before a
-terminating newline (unless PCRE_DOLLAR_ENDONLY is set). This is the same as
-Perl.
-</P>
-<P>
-When PCRE_MULTILINE it is set, the "start of line" and "end of line" constructs
-match immediately following or immediately before any newline in the subject
-string, respectively, as well as at the very start and end. This is equivalent
-to Perl's /m option. If there are no "\n" characters in a subject string, or
-no occurrences of ^ or $ in a pattern, setting PCRE_MULTILINE has no
-effect.
-</P>
-<P>
-<PRE>
-  PCRE_UNGREEDY
-</PRE>
-</P>
-<P>
-This option inverts the "greediness" of the quantifiers so that they are not
-greedy by default, but become greedy if followed by "?". It is not compatible
-with Perl. It can also be set by a (?U) option setting within the pattern.
-</P>
-<P>
-<PRE>
-  PCRE_UTF8
-</PRE>
-</P>
-<P>
-This option causes PCRE to regard both the pattern and the subject as strings
-of UTF-8 characters instead of just byte strings. However, it is available only
-if PCRE has been built to include UTF-8 support. If not, the use of this option
-provokes an error. Support for UTF-8 is new, experimental, and incomplete.
-Details of exactly what it entails are given below.
-</P>
-<LI><A NAME="SEC6" HREF="#TOC1">STUDYING A PATTERN</A>
-<P>
-When a pattern is going to be used several times, it is worth spending more
-time analyzing it in order to speed up the time taken for matching. The
-function <B>pcre_study()</B> takes a pointer to a compiled pattern as its first
-argument, and returns a pointer to a <B>pcre_extra</B> block (another <B>void</B>
-typedef) containing additional information about the pattern; this can be
-passed to <B>pcre_exec()</B>. If no additional information is available, NULL
-is returned.
-</P>
-<P>
-The second argument contains option bits. At present, no options are defined
-for <B>pcre_study()</B>, and this argument should always be zero.
-</P>
-<P>
-The third argument for <B>pcre_study()</B> is a pointer to an error message. If
-studying succeeds (even if no data is returned), the variable it points to is
-set to NULL. Otherwise it points to a textual error message.
-</P>
-<P>
-At present, studying a pattern is useful only for non-anchored patterns that do
-not have a single fixed starting character. A bitmap of possible starting
-characters is created.
-</P>
-<LI><A NAME="SEC7" HREF="#TOC1">LOCALE SUPPORT</A>
-<P>
-PCRE handles caseless matching, and determines whether characters are letters,
-digits, or whatever, by reference to a set of tables. The library contains a
-default set of tables which is created in the default C locale when PCRE is
-compiled. This is used when the final argument of <B>pcre_compile()</B> is NULL,
-and is sufficient for many applications.
-</P>
-<P>
-An alternative set of tables can, however, be supplied. Such tables are built
-by calling the <B>pcre_maketables()</B> function, which has no arguments, in the
-relevant locale. The result can then be passed to <B>pcre_compile()</B> as often
-as necessary. For example, to build and use tables that are appropriate for the
-French locale (where accented characters with codes greater than 128 are
-treated as letters), the following code could be used:
-</P>
-<P>
-<PRE>
-  setlocale(LC_CTYPE, "fr");
-  tables = pcre_maketables();
-  re = pcre_compile(..., tables);
-</PRE>
-</P>
-<P>
-The tables are built in memory that is obtained via <B>pcre_malloc</B>. The
-pointer that is passed to <B>pcre_compile</B> is saved with the compiled
-pattern, and the same tables are used via this pointer by <B>pcre_study()</B>
-and <B>pcre_exec()</B>. Thus for any single pattern, compilation, studying and
-matching all happen in the same locale, but different patterns can be compiled
-in different locales. It is the caller's responsibility to ensure that the
-memory containing the tables remains available for as long as it is needed.
-</P>
-<LI><A NAME="SEC8" HREF="#TOC1">INFORMATION ABOUT A PATTERN</A>
-<P>
-The <B>pcre_fullinfo()</B> function returns information about a compiled
-pattern. It replaces the obsolete <B>pcre_info()</B> function, which is
-nevertheless retained for backwards compability (and is documented below).
-</P>
-<P>
-The first argument for <B>pcre_fullinfo()</B> is a pointer to the compiled
-pattern. The second argument is the result of <B>pcre_study()</B>, or NULL if
-the pattern was not studied. The third argument specifies which piece of
-information is required, while the fourth argument is a pointer to a variable
-to receive the data. The yield of the function is zero for success, or one of
-the following negative numbers:
-</P>
-<P>
-<PRE>
-  PCRE_ERROR_NULL       the argument <I>code</I> was NULL
-                        the argument <I>where</I> was NULL
-  PCRE_ERROR_BADMAGIC   the "magic number" was not found
-  PCRE_ERROR_BADOPTION  the value of <I>what</I> was invalid
-</PRE>
-</P>
-<P>
-The possible values for the third argument are defined in <B>pcre.h</B>, and are
-as follows:
-</P>
-<P>
-<PRE>
-  PCRE_INFO_OPTIONS
-</PRE>
-</P>
-<P>
-Return a copy of the options with which the pattern was compiled. The fourth
-argument should point to au <B>unsigned long int</B> variable. These option bits
-are those specified in the call to <B>pcre_compile()</B>, modified by any
-top-level option settings within the pattern itself, and with the PCRE_ANCHORED
-bit forcibly set if the form of the pattern implies that it can match only at
-the start of a subject string.
-</P>
-<P>
-<PRE>
-  PCRE_INFO_SIZE
-</PRE>
-</P>
-<P>
-Return the size of the compiled pattern, that is, the value that was passed as
-the argument to <B>pcre_malloc()</B> when PCRE was getting memory in which to
-place the compiled data. The fourth argument should point to a <B>size_t</B>
-variable.
-</P>
-<P>
-<PRE>
-  PCRE_INFO_CAPTURECOUNT
-</PRE>
-</P>
-<P>
-Return the number of capturing subpatterns in the pattern. The fourth argument
-should point to an \fbint\fR variable.
-</P>
-<P>
-<PRE>
-  PCRE_INFO_BACKREFMAX
-</PRE>
-</P>
-<P>
-Return the number of the highest back reference in the pattern. The fourth
-argument should point to an <B>int</B> variable. Zero is returned if there are
-no back references.
-</P>
-<P>
-<PRE>
-  PCRE_INFO_FIRSTCHAR
-</PRE>
-</P>
-<P>
-Return information about the first character of any matched string, for a
-non-anchored pattern. If there is a fixed first character, e.g. from a pattern
-such as (cat|cow|coyote), it is returned in the integer pointed to by
-<I>where</I>. Otherwise, if either
-</P>
-<P>
-(a) the pattern was compiled with the PCRE_MULTILINE option, and every branch
-starts with "^", or
-</P>
-<P>
-(b) every branch of the pattern starts with ".*" and PCRE_DOTALL is not set
-(if it were set, the pattern would be anchored),
-</P>
-<P>
--1 is returned, indicating that the pattern matches only at the start of a
-subject string or after any "\n" within the string. Otherwise -2 is returned.
-For anchored patterns, -2 is returned.
-</P>
-<P>
-<PRE>
-  PCRE_INFO_FIRSTTABLE
-</PRE>
-</P>
-<P>
-If the pattern was studied, and this resulted in the construction of a 256-bit
-table indicating a fixed set of characters for the first character in any
-matching string, a pointer to the table is returned. Otherwise NULL is
-returned. The fourth argument should point to an <B>unsigned char *</B>
-variable.
-</P>
-<P>
-<PRE>
-  PCRE_INFO_LASTLITERAL
-</PRE>
-</P>
-<P>
-For a non-anchored pattern, return the value of the rightmost literal character
-which must exist in any matched string, other than at its start. The fourth
-argument should point to an <B>int</B> variable. If there is no such character,
-or if the pattern is anchored, -1 is returned. For example, for the pattern
-/a\d+z\d+/ the returned value is 'z'.
-</P>
-<P>
-The <B>pcre_info()</B> function is now obsolete because its interface is too
-restrictive to return all the available data about a compiled pattern. New
-programs should use <B>pcre_fullinfo()</B> instead. The yield of
-<B>pcre_info()</B> is the number of capturing subpatterns, or one of the
-following negative numbers:
-</P>
-<P>
-<PRE>
-  PCRE_ERROR_NULL       the argument <I>code</I> was NULL
-  PCRE_ERROR_BADMAGIC   the "magic number" was not found
-</PRE>
-</P>
-<P>
-If the <I>optptr</I> argument is not NULL, a copy of the options with which the
-pattern was compiled is placed in the integer it points to (see
-PCRE_INFO_OPTIONS above).
-</P>
-<P>
-If the pattern is not anchored and the <I>firstcharptr</I> argument is not NULL,
-it is used to pass back information about the first character of any matched
-string (see PCRE_INFO_FIRSTCHAR above).
-</P>
-<LI><A NAME="SEC9" HREF="#TOC1">MATCHING A PATTERN</A>
-<P>
-The function <B>pcre_exec()</B> is called to match a subject string against a
-pre-compiled pattern, which is passed in the <I>code</I> argument. If the
-pattern has been studied, the result of the study should be passed in the
-<I>extra</I> argument. Otherwise this must be NULL.
-</P>
-<P>
-The PCRE_ANCHORED option can be passed in the <I>options</I> argument, whose
-unused bits must be zero. However, if a pattern was compiled with
-PCRE_ANCHORED, or turned out to be anchored by virtue of its contents, it
-cannot be made unachored at matching time.
-</P>
-<P>
-There are also three further options that can be set only at matching time:
-</P>
-<P>
-<PRE>
-  PCRE_NOTBOL
-</PRE>
-</P>
-<P>
-The first character of the string is not the beginning of a line, so the
-circumflex metacharacter should not match before it. Setting this without
-PCRE_MULTILINE (at compile time) causes circumflex never to match.
-</P>
-<P>
-<PRE>
-  PCRE_NOTEOL
-</PRE>
-</P>
-<P>
-The end of the string is not the end of a line, so the dollar metacharacter
-should not match it nor (except in multiline mode) a newline immediately before
-it. Setting this without PCRE_MULTILINE (at compile time) causes dollar never
-to match.
-</P>
-<P>
-<PRE>
-  PCRE_NOTEMPTY
-</PRE>
-</P>
-<P>
-An empty string is not considered to be a valid match if this option is set. If
-there are alternatives in the pattern, they are tried. If all the alternatives
-match the empty string, the entire match fails. For example, if the pattern
-</P>
-<P>
-<PRE>
-  a?b?
-</PRE>
-</P>
-<P>
-is applied to a string not beginning with "a" or "b", it matches the empty
-string at the start of the subject. With PCRE_NOTEMPTY set, this match is not
-valid, so PCRE searches further into the string for occurrences of "a" or "b".
-</P>
-<P>
-Perl has no direct equivalent of PCRE_NOTEMPTY, but it does make a special case
-of a pattern match of the empty string within its <B>split()</B> function, and
-when using the /g modifier. It is possible to emulate Perl's behaviour after
-matching a null string by first trying the match again at the same offset with
-PCRE_NOTEMPTY set, and then if that fails by advancing the starting offset (see
-below) and trying an ordinary match again.
-</P>
-<P>
-The subject string is passed as a pointer in <I>subject</I>, a length in
-<I>length</I>, and a starting offset in <I>startoffset</I>. Unlike the pattern
-string, it may contain binary zero characters. When the starting offset is
-zero, the search for a match starts at the beginning of the subject, and this
-is by far the most common case.
-</P>
-<P>
-A non-zero starting offset is useful when searching for another match in the
-same subject by calling <B>pcre_exec()</B> again after a previous success.
-Setting <I>startoffset</I> differs from just passing over a shortened string and
-setting PCRE_NOTBOL in the case of a pattern that begins with any kind of
-lookbehind. For example, consider the pattern
-</P>
-<P>
-<PRE>
-  \Biss\B
-</PRE>
-</P>
-<P>
-which finds occurrences of "iss" in the middle of words. (\B matches only if
-the current position in the subject is not a word boundary.) When applied to
-the string "Mississipi" the first call to <B>pcre_exec()</B> finds the first
-occurrence. If <B>pcre_exec()</B> is called again with just the remainder of the
-subject, namely "issipi", it does not match, because \B is always false at the
-start of the subject, which is deemed to be a word boundary. However, if
-<B>pcre_exec()</B> is passed the entire string again, but with <I>startoffset</I>
-set to 4, it finds the second occurrence of "iss" because it is able to look
-behind the starting point to discover that it is preceded by a letter.
-</P>
-<P>
-If a non-zero starting offset is passed when the pattern is anchored, one
-attempt to match at the given offset is tried. This can only succeed if the
-pattern does not require the match to be at the start of the subject.
-</P>
-<P>
-In general, a pattern matches a certain portion of the subject, and in
-addition, further substrings from the subject may be picked out by parts of the
-pattern. Following the usage in Jeffrey Friedl's book, this is called
-"capturing" in what follows, and the phrase "capturing subpattern" is used for
-a fragment of a pattern that picks out a substring. PCRE supports several other
-kinds of parenthesized subpattern that do not cause substrings to be captured.
-</P>
-<P>
-Captured substrings are returned to the caller via a vector of integer offsets
-whose address is passed in <I>ovector</I>. The number of elements in the vector
-is passed in <I>ovecsize</I>. The first two-thirds of the vector is used to pass
-back captured substrings, each substring using a pair of integers. The
-remaining third of the vector is used as workspace by <B>pcre_exec()</B> while
-matching capturing subpatterns, and is not available for passing back
-information. The length passed in <I>ovecsize</I> should always be a multiple of
-three. If it is not, it is rounded down.
-</P>
-<P>
-When a match has been successful, information about captured substrings is
-returned in pairs of integers, starting at the beginning of <I>ovector</I>, and
-continuing up to two-thirds of its length at the most. The first element of a
-pair is set to the offset of the first character in a substring, and the second
-is set to the offset of the first character after the end of a substring. The
-first pair, <I>ovector[0]</I> and <I>ovector[1]</I>, identify the portion of the
-subject string matched by the entire pattern. The next pair is used for the
-first capturing subpattern, and so on. The value returned by <B>pcre_exec()</B>
-is the number of pairs that have been set. If there are no capturing
-subpatterns, the return value from a successful match is 1, indicating that
-just the first pair of offsets has been set.
-</P>
-<P>
-Some convenience functions are provided for extracting the captured substrings
-as separate strings. These are described in the following section.
-</P>
-<P>
-It is possible for an capturing subpattern number <I>n+1</I> to match some
-part of the subject when subpattern <I>n</I> has not been used at all. For
-example, if the string "abc" is matched against the pattern (a|(z))(bc)
-subpatterns 1 and 3 are matched, but 2 is not. When this happens, both offset
-values corresponding to the unused subpattern are set to -1.
-</P>
-<P>
-If a capturing subpattern is matched repeatedly, it is the last portion of the
-string that it matched that gets returned.
-</P>
-<P>
-If the vector is too small to hold all the captured substrings, it is used as
-far as possible (up to two-thirds of its length), and the function returns a
-value of zero. In particular, if the substring offsets are not of interest,
-<B>pcre_exec()</B> may be called with <I>ovector</I> passed as NULL and
-<I>ovecsize</I> as zero. However, if the pattern contains back references and
-the <I>ovector</I> isn't big enough to remember the related substrings, PCRE has
-to get additional memory for use during matching. Thus it is usually advisable
-to supply an <I>ovector</I>.
-</P>
-<P>
-Note that <B>pcre_info()</B> can be used to find out how many capturing
-subpatterns there are in a compiled pattern. The smallest size for
-<I>ovector</I> that will allow for <I>n</I> captured substrings in addition to
-the offsets of the substring matched by the whole pattern is (<I>n</I>+1)*3.
-</P>
-<P>
-If <B>pcre_exec()</B> fails, it returns a negative number. The following are
-defined in the header file:
-</P>
-<P>
-<PRE>
-  PCRE_ERROR_NOMATCH        (-1)
-</PRE>
-</P>
-<P>
-The subject string did not match the pattern.
-</P>
-<P>
-<PRE>
-  PCRE_ERROR_NULL           (-2)
-</PRE>
-</P>
-<P>
-Either <I>code</I> or <I>subject</I> was passed as NULL, or <I>ovector</I> was
-NULL and <I>ovecsize</I> was not zero.
-</P>
-<P>
-<PRE>
-  PCRE_ERROR_BADOPTION      (-3)
-</PRE>
-</P>
-<P>
-An unrecognized bit was set in the <I>options</I> argument.
-</P>
-<P>
-<PRE>
-  PCRE_ERROR_BADMAGIC       (-4)
-</PRE>
-</P>
-<P>
-PCRE stores a 4-byte "magic number" at the start of the compiled code, to catch
-the case when it is passed a junk pointer. This is the error it gives when the
-magic number isn't present.
-</P>
-<P>
-<PRE>
-  PCRE_ERROR_UNKNOWN_NODE   (-5)
-</PRE>
-</P>
-<P>
-While running the pattern match, an unknown item was encountered in the
-compiled pattern. This error could be caused by a bug in PCRE or by overwriting
-of the compiled pattern.
-</P>
-<P>
-<PRE>
-  PCRE_ERROR_NOMEMORY       (-6)
-</PRE>
-</P>
-<P>
-If a pattern contains back references, but the <I>ovector</I> that is passed to
-<B>pcre_exec()</B> is not big enough to remember the referenced substrings, PCRE
-gets a block of memory at the start of matching to use for this purpose. If the
-call via <B>pcre_malloc()</B> fails, this error is given. The memory is freed at
-the end of matching.
-</P>
-<LI><A NAME="SEC10" HREF="#TOC1">EXTRACTING CAPTURED SUBSTRINGS</A>
-<P>
-Captured substrings can be accessed directly by using the offsets returned by
-<B>pcre_exec()</B> in <I>ovector</I>. For convenience, the functions
-<B>pcre_copy_substring()</B>, <B>pcre_get_substring()</B>, and
-<B>pcre_get_substring_list()</B> are provided for extracting captured substrings
-as new, separate, zero-terminated strings. A substring that contains a binary
-zero is correctly extracted and has a further zero added on the end, but the
-result does not, of course, function as a C string.
-</P>
-<P>
-The first three arguments are the same for all three functions: <I>subject</I>
-is the subject string which has just been successfully matched, <I>ovector</I>
-is a pointer to the vector of integer offsets that was passed to
-<B>pcre_exec()</B>, and <I>stringcount</I> is the number of substrings that
-were captured by the match, including the substring that matched the entire
-regular expression. This is the value returned by <B>pcre_exec</B> if it
-is greater than zero. If <B>pcre_exec()</B> returned zero, indicating that it
-ran out of space in <I>ovector</I>, the value passed as <I>stringcount</I> should
-be the size of the vector divided by three.
-</P>
-<P>
-The functions <B>pcre_copy_substring()</B> and <B>pcre_get_substring()</B>
-extract a single substring, whose number is given as <I>stringnumber</I>. A
-value of zero extracts the substring that matched the entire pattern, while
-higher values extract the captured substrings. For <B>pcre_copy_substring()</B>,
-the string is placed in <I>buffer</I>, whose length is given by
-<I>buffersize</I>, while for <B>pcre_get_substring()</B> a new block of memory is
-obtained via <B>pcre_malloc</B>, and its address is returned via
-<I>stringptr</I>. The yield of the function is the length of the string, not
-including the terminating zero, or one of
-</P>
-<P>
-<PRE>
-  PCRE_ERROR_NOMEMORY       (-6)
-</PRE>
-</P>
-<P>
-The buffer was too small for <B>pcre_copy_substring()</B>, or the attempt to get
-memory failed for <B>pcre_get_substring()</B>.
-</P>
-<P>
-<PRE>
-  PCRE_ERROR_NOSUBSTRING    (-7)
-</PRE>
-</P>
-<P>
-There is no substring whose number is <I>stringnumber</I>.
-</P>
-<P>
-The <B>pcre_get_substring_list()</B> function extracts all available substrings
-and builds a list of pointers to them. All this is done in a single block of
-memory which is obtained via <B>pcre_malloc</B>. The address of the memory block
-is returned via <I>listptr</I>, which is also the start of the list of string
-pointers. The end of the list is marked by a NULL pointer. The yield of the
-function is zero if all went well, or
-</P>
-<P>
-<PRE>
-  PCRE_ERROR_NOMEMORY       (-6)
-</PRE>
-</P>
-<P>
-if the attempt to get the memory block failed.
-</P>
-<P>
-When any of these functions encounter a substring that is unset, which can
-happen when capturing subpattern number <I>n+1</I> matches some part of the
-subject, but subpattern <I>n</I> has not been used at all, they return an empty
-string. This can be distinguished from a genuine zero-length substring by
-inspecting the appropriate offset in <I>ovector</I>, which is negative for unset
-substrings.
-</P>
-<P>
-The two convenience functions <B>pcre_free_substring()</B> and
-<B>pcre_free_substring_list()</B> can be used to free the memory returned by
-a previous call of <B>pcre_get_substring()</B> or
-<B>pcre_get_substring_list()</B>, respectively. They do nothing more than call
-the function pointed to by <B>pcre_free</B>, which of course could be called
-directly from a C program. However, PCRE is used in some situations where it is
-linked via a special interface to another programming language which cannot use
-<B>pcre_free</B> directly; it is for these cases that the functions are
-provided.
-</P>
-<LI><A NAME="SEC11" HREF="#TOC1">LIMITATIONS</A>
-<P>
-There are some size limitations in PCRE but it is hoped that they will never in
-practice be relevant.
-The maximum length of a compiled pattern is 65539 (sic) bytes.
-All values in repeating quantifiers must be less than 65536.
-The maximum number of capturing subpatterns is 99.
-The maximum number of all parenthesized subpatterns, including capturing
-subpatterns, assertions, and other types of subpattern, is 200.
-</P>
-<P>
-The maximum length of a subject string is the largest positive number that an
-integer variable can hold. However, PCRE uses recursion to handle subpatterns
-and indefinite repetition. This means that the available stack space may limit
-the size of a subject string that can be processed by certain patterns.
-</P>
-<LI><A NAME="SEC12" HREF="#TOC1">DIFFERENCES FROM PERL</A>
-<P>
-The differences described here are with respect to Perl 5.005.
-</P>
-<P>
-1. By default, a whitespace character is any character that the C library
-function <B>isspace()</B> recognizes, though it is possible to compile PCRE with
-alternative character type tables. Normally <B>isspace()</B> matches space,
-formfeed, newline, carriage return, horizontal tab, and vertical tab. Perl 5
-no longer includes vertical tab in its set of whitespace characters. The \v
-escape that was in the Perl documentation for a long time was never in fact
-recognized. However, the character itself was treated as whitespace at least
-up to 5.002. In 5.004 and 5.005 it does not match \s.
-</P>
-<P>
-2. PCRE does not allow repeat quantifiers on lookahead assertions. Perl permits
-them, but they do not mean what you might think. For example, (?!a){3} does
-not assert that the next three characters are not "a". It just asserts that the
-next character is not "a" three times.
-</P>
-<P>
-3. Capturing subpatterns that occur inside negative lookahead assertions are
-counted, but their entries in the offsets vector are never set. Perl sets its
-numerical variables from any such patterns that are matched before the
-assertion fails to match something (thereby succeeding), but only if the
-negative lookahead assertion contains just one branch.
-</P>
-<P>
-4. Though binary zero characters are supported in the subject string, they are
-not allowed in a pattern string because it is passed as a normal C string,
-terminated by zero. The escape sequence "\0" can be used in the pattern to
-represent a binary zero.
-</P>
-<P>
-5. The following Perl escape sequences are not supported: \l, \u, \L, \U,
-\E, \Q. In fact these are implemented by Perl's general string-handling and
-are not part of its pattern matching engine.
-</P>
-<P>
-6. The Perl \G assertion is not supported as it is not relevant to single
-pattern matches.
-</P>
-<P>
-7. Fairly obviously, PCRE does not support the (?{code}) and (?p{code})
-constructions. However, there is some experimental support for recursive
-patterns using the non-Perl item (?R).
-</P>
-<P>
-8. There are at the time of writing some oddities in Perl 5.005_02 concerned
-with the settings of captured strings when part of a pattern is repeated. For
-example, matching "aba" against the pattern /^(a(b)?)+$/ sets $2 to the value
-"b", but matching "aabbaa" against /^(aa(bb)?)+$/ leaves $2 unset. However, if
-the pattern is changed to /^(aa(b(b))?)+$/ then $2 (and $3) are set.
-</P>
-<P>
-In Perl 5.004 $2 is set in both cases, and that is also true of PCRE. If in the
-future Perl changes to a consistent state that is different, PCRE may change to
-follow.
-</P>
-<P>
-9. Another as yet unresolved discrepancy is that in Perl 5.005_02 the pattern
-/^(a)?(?(1)a|b)+$/ matches the string "a", whereas in PCRE it does not.
-However, in both Perl and PCRE /^(a)?a/ matched against "a" leaves $1 unset.
-</P>
-<P>
-10. PCRE provides some extensions to the Perl regular expression facilities:
-</P>
-<P>
-(a) Although lookbehind assertions must match fixed length strings, each
-alternative branch of a lookbehind assertion can match a different length of
-string. Perl 5.005 requires them all to have the same length.
-</P>
-<P>
-(b) If PCRE_DOLLAR_ENDONLY is set and PCRE_MULTILINE is not set, the $ meta-
-character matches only at the very end of the string.
-</P>
-<P>
-(c) If PCRE_EXTRA is set, a backslash followed by a letter with no special
-meaning is faulted.
-</P>
-<P>
-(d) If PCRE_UNGREEDY is set, the greediness of the repetition quantifiers is
-inverted, that is, by default they are not greedy, but if followed by a
-question mark they are.
-</P>
-<P>
-(e) PCRE_ANCHORED can be used to force a pattern to be tried only at the start
-of the subject.
-</P>
-<P>
-(f) The PCRE_NOTBOL, PCRE_NOTEOL, and PCRE_NOTEMPTY options for
-<B>pcre_exec()</B> have no Perl equivalents.
-</P>
-<P>
-(g) The (?R) construct allows for recursive pattern matching (Perl 5.6 can do
-this using the (?p{code}) construct, which PCRE cannot of course support.)
-</P>
-<LI><A NAME="SEC13" HREF="#TOC1">REGULAR EXPRESSION DETAILS</A>
-<P>
-The syntax and semantics of the regular expressions supported by PCRE are
-described below. Regular expressions are also described in the Perl
-documentation and in a number of other books, some of which have copious
-examples. Jeffrey Friedl's "Mastering Regular Expressions", published by
-O'Reilly (ISBN 1-56592-257), covers them in great detail.
-</P>
-<P>
-The description here is intended as reference documentation. The basic
-operation of PCRE is on strings of bytes. However, there is the beginnings of
-some support for UTF-8 character strings. To use this support you must
-configure PCRE to include it, and then call <B>pcre_compile()</B> with the
-PCRE_UTF8 option. How this affects the pattern matching is described in the
-final section of this document.
-</P>
-<P>
-A regular expression is a pattern that is matched against a subject string from
-left to right. Most characters stand for themselves in a pattern, and match the
-corresponding characters in the subject. As a trivial example, the pattern
-</P>
-<P>
-<PRE>
-  The quick brown fox
-</PRE>
-</P>
-<P>
-matches a portion of a subject string that is identical to itself. The power of
-regular expressions comes from the ability to include alternatives and
-repetitions in the pattern. These are encoded in the pattern by the use of
-<I>meta-characters</I>, which do not stand for themselves but instead are
-interpreted in some special way.
-</P>
-<P>
-There are two different sets of meta-characters: those that are recognized
-anywhere in the pattern except within square brackets, and those that are
-recognized in square brackets. Outside square brackets, the meta-characters are
-as follows:
-</P>
-<P>
-<PRE>
-  \      general escape character with several uses
-  ^      assert start of subject (or line, in multiline mode)
-  $      assert end of subject (or line, in multiline mode)
-  .      match any character except newline (by default)
-  [      start character class definition
-  |      start of alternative branch
-  (      start subpattern
-  )      end subpattern
-  ?      extends the meaning of (
-         also 0 or 1 quantifier
-         also quantifier minimizer
-  *      0 or more quantifier
-  +      1 or more quantifier
-  {      start min/max quantifier
-</PRE>
-</P>
-<P>
-Part of a pattern that is in square brackets is called a "character class". In
-a character class the only meta-characters are:
-</P>
-<P>
-<PRE>
-  \      general escape character
-  ^      negate the class, but only if the first character
-  -      indicates character range
-  ]      terminates the character class
-</PRE>
-</P>
-<P>
-The following sections describe the use of each of the meta-characters.
-</P>
-<LI><A NAME="SEC14" HREF="#TOC1">BACKSLASH</A>
-<P>
-The backslash character has several uses. Firstly, if it is followed by a
-non-alphameric character, it takes away any special meaning that character may
-have. This use of backslash as an escape character applies both inside and
-outside character classes.
-</P>
-<P>
-For example, if you want to match a "*" character, you write "\*" in the
-pattern. This applies whether or not the following character would otherwise be
-interpreted as a meta-character, so it is always safe to precede a
-non-alphameric with "\" to specify that it stands for itself. In particular,
-if you want to match a backslash, you write "\\".
-</P>
-<P>
-If a pattern is compiled with the PCRE_EXTENDED option, whitespace in the
-pattern (other than in a character class) and characters between a "#" outside
-a character class and the next newline character are ignored. An escaping
-backslash can be used to include a whitespace or "#" character as part of the
-pattern.
-</P>
-<P>
-A second use of backslash provides a way of encoding non-printing characters
-in patterns in a visible manner. There is no restriction on the appearance of
-non-printing characters, apart from the binary zero that terminates a pattern,
-but when a pattern is being prepared by text editing, it is usually easier to
-use one of the following escape sequences than the binary character it
-represents:
-</P>
-<P>
-<PRE>
-  \a     alarm, that is, the BEL character (hex 07)
-  \cx    "control-x", where x is any character
-  \e     escape (hex 1B)
-  \f     formfeed (hex 0C)
-  \n     newline (hex 0A)
-  \r     carriage return (hex 0D)
-  \t     tab (hex 09)
-  \xhh   character with hex code hh
-  \ddd   character with octal code ddd, or backreference
-</PRE>
-</P>
-<P>
-The precise effect of "\cx" is as follows: if "x" is a lower case letter, it
-is converted to upper case. Then bit 6 of the character (hex 40) is inverted.
-Thus "\cz" becomes hex 1A, but "\c{" becomes hex 3B, while "\c;" becomes hex
-7B.
-</P>
-<P>
-After "\x", up to two hexadecimal digits are read (letters can be in upper or
-lower case).
-</P>
-<P>
-After "\0" up to two further octal digits are read. In both cases, if there
-are fewer than two digits, just those that are present are used. Thus the
-sequence "\0\x\07" specifies two binary zeros followed by a BEL character.
-Make sure you supply two digits after the initial zero if the character that
-follows is itself an octal digit.
-</P>
-<P>
-The handling of a backslash followed by a digit other than 0 is complicated.
-Outside a character class, PCRE reads it and any following digits as a decimal
-number. If the number is less than 10, or if there have been at least that many
-previous capturing left parentheses in the expression, the entire sequence is
-taken as a <I>back reference</I>. A description of how this works is given
-later, following the discussion of parenthesized subpatterns.
-</P>
-<P>
-Inside a character class, or if the decimal number is greater than 9 and there
-have not been that many capturing subpatterns, PCRE re-reads up to three octal
-digits following the backslash, and generates a single byte from the least
-significant 8 bits of the value. Any subsequent digits stand for themselves.
-For example:
-</P>
-<P>
-<PRE>
-  \040   is another way of writing a space
-  \40    is the same, provided there are fewer than 40
-            previous capturing subpatterns
-  \7     is always a back reference
-  \11    might be a back reference, or another way of
-            writing a tab
-  \011   is always a tab
-  \0113  is a tab followed by the character "3"
-  \113   is the character with octal code 113 (since there
-            can be no more than 99 back references)
-  \377   is a byte consisting entirely of 1 bits
-  \81    is either a back reference, or a binary zero
-            followed by the two characters "8" and "1"
-</PRE>
-</P>
-<P>
-Note that octal values of 100 or greater must not be introduced by a leading
-zero, because no more than three octal digits are ever read.
-</P>
-<P>
-All the sequences that define a single byte value can be used both inside and
-outside character classes. In addition, inside a character class, the sequence
-"\b" is interpreted as the backspace character (hex 08). Outside a character
-class it has a different meaning (see below).
-</P>
-<P>
-The third use of backslash is for specifying generic character types:
-</P>
-<P>
-<PRE>
-  \d     any decimal digit
-  \D     any character that is not a decimal digit
-  \s     any whitespace character
-  \S     any character that is not a whitespace character
-  \w     any "word" character
-  \W     any "non-word" character
-</PRE>
-</P>
-<P>
-Each pair of escape sequences partitions the complete set of characters into
-two disjoint sets. Any given character matches one, and only one, of each pair.
-</P>
-<P>
-A "word" character is any letter or digit or the underscore character, that is,
-any character which can be part of a Perl "word". The definition of letters and
-digits is controlled by PCRE's character tables, and may vary if locale-
-specific matching is taking place (see "Locale support" above). For example, in
-the "fr" (French) locale, some character codes greater than 128 are used for
-accented letters, and these are matched by \w.
-</P>
-<P>
-These character type sequences can appear both inside and outside character
-classes. They each match one character of the appropriate type. If the current
-matching point is at the end of the subject string, all of them fail, since
-there is no character to match.
-</P>
-<P>
-The fourth use of backslash is for certain simple assertions. An assertion
-specifies a condition that has to be met at a particular point in a match,
-without consuming any characters from the subject string. The use of
-subpatterns for more complicated assertions is described below. The backslashed
-assertions are
-</P>
-<P>
-<PRE>
-  \b     word boundary
-  \B     not a word boundary
-  \A     start of subject (independent of multiline mode)
-  \Z     end of subject or newline at end (independent of multiline mode)
-  \z     end of subject (independent of multiline mode)
-</PRE>
-</P>
-<P>
-These assertions may not appear in character classes (but note that "\b" has a
-different meaning, namely the backspace character, inside a character class).
-</P>
-<P>
-A word boundary is a position in the subject string where the current character
-and the previous character do not both match \w or \W (i.e. one matches
-\w and the other matches \W), or the start or end of the string if the
-first or last character matches \w, respectively.
-</P>
-<P>
-The \A, \Z, and \z assertions differ from the traditional circumflex and
-dollar (described below) in that they only ever match at the very start and end
-of the subject string, whatever options are set. They are not affected by the
-PCRE_NOTBOL or PCRE_NOTEOL options. If the <I>startoffset</I> argument of
-<B>pcre_exec()</B> is non-zero, \A can never match. The difference between \Z
-and \z is that \Z matches before a newline that is the last character of the
-string as well as at the end of the string, whereas \z matches only at the
-end.
-</P>
-<LI><A NAME="SEC15" HREF="#TOC1">CIRCUMFLEX AND DOLLAR</A>
-<P>
-Outside a character class, in the default matching mode, the circumflex
-character is an assertion which is true only if the current matching point is
-at the start of the subject string. If the <I>startoffset</I> argument of
-<B>pcre_exec()</B> is non-zero, circumflex can never match. Inside a character
-class, circumflex has an entirely different meaning (see below).
-</P>
-<P>
-Circumflex need not be the first character of the pattern if a number of
-alternatives are involved, but it should be the first thing in each alternative
-in which it appears if the pattern is ever to match that branch. If all
-possible alternatives start with a circumflex, that is, if the pattern is
-constrained to match only at the start of the subject, it is said to be an
-"anchored" pattern. (There are also other constructs that can cause a pattern
-to be anchored.)
-</P>
-<P>
-A dollar character is an assertion which is true only if the current matching
-point is at the end of the subject string, or immediately before a newline
-character that is the last character in the string (by default). Dollar need
-not be the last character of the pattern if a number of alternatives are
-involved, but it should be the last item in any branch in which it appears.
-Dollar has no special meaning in a character class.
-</P>
-<P>
-The meaning of dollar can be changed so that it matches only at the very end of
-the string, by setting the PCRE_DOLLAR_ENDONLY option at compile or matching
-time. This does not affect the \Z assertion.
-</P>
-<P>
-The meanings of the circumflex and dollar characters are changed if the
-PCRE_MULTILINE option is set. When this is the case, they match immediately
-after and immediately before an internal "\n" character, respectively, in
-addition to matching at the start and end of the subject string. For example,
-the pattern /^abc$/ matches the subject string "def\nabc" in multiline mode,
-but not otherwise. Consequently, patterns that are anchored in single line mode
-because all branches start with "^" are not anchored in multiline mode, and a
-match for circumflex is possible when the <I>startoffset</I> argument of
-<B>pcre_exec()</B> is non-zero. The PCRE_DOLLAR_ENDONLY option is ignored if
-PCRE_MULTILINE is set.
-</P>
-<P>
-Note that the sequences \A, \Z, and \z can be used to match the start and
-end of the subject in both modes, and if all branches of a pattern start with
-\A is it always anchored, whether PCRE_MULTILINE is set or not.
-</P>
-<LI><A NAME="SEC16" HREF="#TOC1">FULL STOP (PERIOD, DOT)</A>
-<P>
-Outside a character class, a dot in the pattern matches any one character in
-the subject, including a non-printing character, but not (by default) newline.
-If the PCRE_DOTALL option is set, dots match newlines as well. The handling of
-dot is entirely independent of the handling of circumflex and dollar, the only
-relationship being that they both involve newline characters. Dot has no
-special meaning in a character class.
-</P>
-<LI><A NAME="SEC17" HREF="#TOC1">SQUARE BRACKETS</A>
-<P>
-An opening square bracket introduces a character class, terminated by a closing
-square bracket. A closing square bracket on its own is not special. If a
-closing square bracket is required as a member of the class, it should be the
-first data character in the class (after an initial circumflex, if present) or
-escaped with a backslash.
-</P>
-<P>
-A character class matches a single character in the subject; the character must
-be in the set of characters defined by the class, unless the first character in
-the class is a circumflex, in which case the subject character must not be in
-the set defined by the class. If a circumflex is actually required as a member
-of the class, ensure it is not the first character, or escape it with a
-backslash.
-</P>
-<P>
-For example, the character class [aeiou] matches any lower case vowel, while
-[^aeiou] matches any character that is not a lower case vowel. Note that a
-circumflex is just a convenient notation for specifying the characters which
-are in the class by enumerating those that are not. It is not an assertion: it
-still consumes a character from the subject string, and fails if the current
-pointer is at the end of the string.
-</P>
-<P>
-When caseless matching is set, any letters in a class represent both their
-upper case and lower case versions, so for example, a caseless [aeiou] matches
-"A" as well as "a", and a caseless [^aeiou] does not match "A", whereas a
-caseful version would.
-</P>
-<P>
-The newline character is never treated in any special way in character classes,
-whatever the setting of the PCRE_DOTALL or PCRE_MULTILINE options is. A class
-such as [^a] will always match a newline.
-</P>
-<P>
-The minus (hyphen) character can be used to specify a range of characters in a
-character class. For example, [d-m] matches any letter between d and m,
-inclusive. If a minus character is required in a class, it must be escaped with
-a backslash or appear in a position where it cannot be interpreted as
-indicating a range, typically as the first or last character in the class.
-</P>
-<P>
-It is not possible to have the literal character "]" as the end character of a
-range. A pattern such as [W-]46] is interpreted as a class of two characters
-("W" and "-") followed by a literal string "46]", so it would match "W46]" or
-"-46]". However, if the "]" is escaped with a backslash it is interpreted as
-the end of range, so [W-\]46] is interpreted as a single class containing a
-range followed by two separate characters. The octal or hexadecimal
-representation of "]" can also be used to end a range.
-</P>
-<P>
-Ranges operate in ASCII collating sequence. They can also be used for
-characters specified numerically, for example [\000-\037]. If a range that
-includes letters is used when caseless matching is set, it matches the letters
-in either case. For example, [W-c] is equivalent to [][\^_`wxyzabc], matched
-caselessly, and if character tables for the "fr" locale are in use,
-[\xc8-\xcb] matches accented E characters in both cases.
-</P>
-<P>
-The character types \d, \D, \s, \S, \w, and \W may also appear in a
-character class, and add the characters that they match to the class. For
-example, [\dABCDEF] matches any hexadecimal digit. A circumflex can
-conveniently be used with the upper case character types to specify a more
-restricted set of characters than the matching lower case type. For example,
-the class [^\W_] matches any letter or digit, but not underscore.
-</P>
-<P>
-All non-alphameric characters other than \, -, ^ (at the start) and the
-terminating ] are non-special in character classes, but it does no harm if they
-are escaped.
-</P>
-<LI><A NAME="SEC18" HREF="#TOC1">POSIX CHARACTER CLASSES</A>
-<P>
-Perl 5.6 (not yet released at the time of writing) is going to support the
-POSIX notation for character classes, which uses names enclosed by [: and :]
-within the enclosing square brackets. PCRE supports this notation. For example,
-</P>
-<P>
-<PRE>
-  [01[:alpha:]%]
-</PRE>
-</P>
-<P>
-matches "0", "1", any alphabetic character, or "%". The supported class names
-are
-</P>
-<P>
-<PRE>
-  alnum    letters and digits
-  alpha    letters
-  ascii    character codes 0 - 127
-  cntrl    control characters
-  digit    decimal digits (same as \d)
-  graph    printing characters, excluding space
-  lower    lower case letters
-  print    printing characters, including space
-  punct    printing characters, excluding letters and digits
-  space    white space (same as \s)
-  upper    upper case letters
-  word     "word" characters (same as \w)
-  xdigit   hexadecimal digits
-</PRE>
-</P>
-<P>
-The names "ascii" and "word" are Perl extensions. Another Perl extension is
-negation, which is indicated by a ^ character after the colon. For example,
-</P>
-<P>
-<PRE>
-  [12[:^digit:]]
-</PRE>
-</P>
-<P>
-matches "1", "2", or any non-digit. PCRE (and Perl) also recogize the POSIX
-syntax [.ch.] and [=ch=] where "ch" is a "collating element", but these are not
-supported, and an error is given if they are encountered.
-</P>
-<LI><A NAME="SEC19" HREF="#TOC1">VERTICAL BAR</A>
-<P>
-Vertical bar characters are used to separate alternative patterns. For example,
-the pattern
-</P>
-<P>
-<PRE>
-  gilbert|sullivan
-</PRE>
-</P>
-<P>
-matches either "gilbert" or "sullivan". Any number of alternatives may appear,
-and an empty alternative is permitted (matching the empty string).
-The matching process tries each alternative in turn, from left to right,
-and the first one that succeeds is used. If the alternatives are within a
-subpattern (defined below), "succeeds" means matching the rest of the main
-pattern as well as the alternative in the subpattern.
-</P>
-<LI><A NAME="SEC20" HREF="#TOC1">INTERNAL OPTION SETTING</A>
-<P>
-The settings of PCRE_CASELESS, PCRE_MULTILINE, PCRE_DOTALL, and PCRE_EXTENDED
-can be changed from within the pattern by a sequence of Perl option letters
-enclosed between "(?" and ")". The option letters are
-</P>
-<P>
-<PRE>
-  i  for PCRE_CASELESS
-  m  for PCRE_MULTILINE
-  s  for PCRE_DOTALL
-  x  for PCRE_EXTENDED
-</PRE>
-</P>
-<P>
-For example, (?im) sets caseless, multiline matching. It is also possible to
-unset these options by preceding the letter with a hyphen, and a combined
-setting and unsetting such as (?im-sx), which sets PCRE_CASELESS and
-PCRE_MULTILINE while unsetting PCRE_DOTALL and PCRE_EXTENDED, is also
-permitted. If a letter appears both before and after the hyphen, the option is
-unset.
-</P>
-<P>
-The scope of these option changes depends on where in the pattern the setting
-occurs. For settings that are outside any subpattern (defined below), the
-effect is the same as if the options were set or unset at the start of
-matching. The following patterns all behave in exactly the same way:
-</P>
-<P>
-<PRE>
-  (?i)abc
-  a(?i)bc
-  ab(?i)c
-  abc(?i)
-</PRE>
-</P>
-<P>
-which in turn is the same as compiling the pattern abc with PCRE_CASELESS set.
-In other words, such "top level" settings apply to the whole pattern (unless
-there are other changes inside subpatterns). If there is more than one setting
-of the same option at top level, the rightmost setting is used.
-</P>
-<P>
-If an option change occurs inside a subpattern, the effect is different. This
-is a change of behaviour in Perl 5.005. An option change inside a subpattern
-affects only that part of the subpattern that follows it, so
-</P>
-<P>
-<PRE>
-  (a(?i)b)c
-</PRE>
-</P>
-<P>
-matches abc and aBc and no other strings (assuming PCRE_CASELESS is not used).
-By this means, options can be made to have different settings in different
-parts of the pattern. Any changes made in one alternative do carry on
-into subsequent branches within the same subpattern. For example,
-</P>
-<P>
-<PRE>
-  (a(?i)b|c)
-</PRE>
-</P>
-<P>
-matches "ab", "aB", "c", and "C", even though when matching "C" the first
-branch is abandoned before the option setting. This is because the effects of
-option settings happen at compile time. There would be some very weird
-behaviour otherwise.
-</P>
-<P>
-The PCRE-specific options PCRE_UNGREEDY and PCRE_EXTRA can be changed in the
-same way as the Perl-compatible options by using the characters U and X
-respectively. The (?X) flag setting is special in that it must always occur
-earlier in the pattern than any of the additional features it turns on, even
-when it is at top level. It is best put at the start.
-</P>
-<LI><A NAME="SEC21" HREF="#TOC1">SUBPATTERNS</A>
-<P>
-Subpatterns are delimited by parentheses (round brackets), which can be nested.
-Marking part of a pattern as a subpattern does two things:
-</P>
-<P>
-1. It localizes a set of alternatives. For example, the pattern
-</P>
-<P>
-<PRE>
-  cat(aract|erpillar|)
-</PRE>
-</P>
-<P>
-matches one of the words "cat", "cataract", or "caterpillar". Without the
-parentheses, it would match "cataract", "erpillar" or the empty string.
-</P>
-<P>
-2. It sets up the subpattern as a capturing subpattern (as defined above).
-When the whole pattern matches, that portion of the subject string that matched
-the subpattern is passed back to the caller via the <I>ovector</I> argument of
-<B>pcre_exec()</B>. Opening parentheses are counted from left to right (starting
-from 1) to obtain the numbers of the capturing subpatterns.
-</P>
-<P>
-For example, if the string "the red king" is matched against the pattern
-</P>
-<P>
-<PRE>
-  the ((red|white) (king|queen))
-</PRE>
-</P>
-<P>
-the captured substrings are "red king", "red", and "king", and are numbered 1,
-2, and 3.
-</P>
-<P>
-The fact that plain parentheses fulfil two functions is not always helpful.
-There are often times when a grouping subpattern is required without a
-capturing requirement. If an opening parenthesis is followed by "?:", the
-subpattern does not do any capturing, and is not counted when computing the
-number of any subsequent capturing subpatterns. For example, if the string "the
-white queen" is matched against the pattern
-</P>
-<P>
-<PRE>
-  the ((?:red|white) (king|queen))
-</PRE>
-</P>
-<P>
-the captured substrings are "white queen" and "queen", and are numbered 1 and
-2. The maximum number of captured substrings is 99, and the maximum number of
-all subpatterns, both capturing and non-capturing, is 200.
-</P>
-<P>
-As a convenient shorthand, if any option settings are required at the start of
-a non-capturing subpattern, the option letters may appear between the "?" and
-the ":". Thus the two patterns
-</P>
-<P>
-<PRE>
-  (?i:saturday|sunday)
-  (?:(?i)saturday|sunday)
-</PRE>
-</P>
-<P>
-match exactly the same set of strings. Because alternative branches are tried
-from left to right, and options are not reset until the end of the subpattern
-is reached, an option setting in one branch does affect subsequent branches, so
-the above patterns match "SUNDAY" as well as "Saturday".
-</P>
-<LI><A NAME="SEC22" HREF="#TOC1">REPETITION</A>
-<P>
-Repetition is specified by quantifiers, which can follow any of the following
-items:
-</P>
-<P>
-<PRE>
-  a single character, possibly escaped
-  the . metacharacter
-  a character class
-  a back reference (see next section)
-  a parenthesized subpattern (unless it is an assertion - see below)
-</PRE>
-</P>
-<P>
-The general repetition quantifier specifies a minimum and maximum number of
-permitted matches, by giving the two numbers in curly brackets (braces),
-separated by a comma. The numbers must be less than 65536, and the first must
-be less than or equal to the second. For example:
-</P>
-<P>
-<PRE>
-  z{2,4}
-</PRE>
-</P>
-<P>
-matches "zz", "zzz", or "zzzz". A closing brace on its own is not a special
-character. If the second number is omitted, but the comma is present, there is
-no upper limit; if the second number and the comma are both omitted, the
-quantifier specifies an exact number of required matches. Thus
-</P>
-<P>
-<PRE>
-  [aeiou]{3,}
-</PRE>
-</P>
-<P>
-matches at least 3 successive vowels, but may match many more, while
-</P>
-<P>
-<PRE>
-  \d{8}
-</PRE>
-</P>
-<P>
-matches exactly 8 digits. An opening curly bracket that appears in a position
-where a quantifier is not allowed, or one that does not match the syntax of a
-quantifier, is taken as a literal character. For example, {,6} is not a
-quantifier, but a literal string of four characters.
-</P>
-<P>
-The quantifier {0} is permitted, causing the expression to behave as if the
-previous item and the quantifier were not present.
-</P>
-<P>
-For convenience (and historical compatibility) the three most common
-quantifiers have single-character abbreviations:
-</P>
-<P>
-<PRE>
-  *    is equivalent to {0,}
-  +    is equivalent to {1,}
-  ?    is equivalent to {0,1}
-</PRE>
-</P>
-<P>
-It is possible to construct infinite loops by following a subpattern that can
-match no characters with a quantifier that has no upper limit, for example:
-</P>
-<P>
-<PRE>
-  (a?)*
-</PRE>
-</P>
-<P>
-Earlier versions of Perl and PCRE used to give an error at compile time for
-such patterns. However, because there are cases where this can be useful, such
-patterns are now accepted, but if any repetition of the subpattern does in fact
-match no characters, the loop is forcibly broken.
-</P>
-<P>
-By default, the quantifiers are "greedy", that is, they match as much as
-possible (up to the maximum number of permitted times), without causing the
-rest of the pattern to fail. The classic example of where this gives problems
-is in trying to match comments in C programs. These appear between the
-sequences /* and */ and within the sequence, individual * and / characters may
-appear. An attempt to match C comments by applying the pattern
-</P>
-<P>
-<PRE>
-  /\*.*\*/
-</PRE>
-</P>
-<P>
-to the string
-</P>
-<P>
-<PRE>
-  /* first command */  not comment  /* second comment */
-</PRE>
-</P>
-<P>
-fails, because it matches the entire string owing to the greediness of the .*
-item.
-</P>
-<P>
-However, if a quantifier is followed by a question mark, it ceases to be
-greedy, and instead matches the minimum number of times possible, so the
-pattern
-</P>
-<P>
-<PRE>
-  /\*.*?\*/
-</PRE>
-</P>
-<P>
-does the right thing with the C comments. The meaning of the various
-quantifiers is not otherwise changed, just the preferred number of matches.
-Do not confuse this use of question mark with its use as a quantifier in its
-own right. Because it has two uses, it can sometimes appear doubled, as in
-</P>
-<P>
-<PRE>
-  \d??\d
-</PRE>
-</P>
-<P>
-which matches one digit by preference, but can match two if that is the only
-way the rest of the pattern matches.
-</P>
-<P>
-If the PCRE_UNGREEDY option is set (an option which is not available in Perl),
-the quantifiers are not greedy by default, but individual ones can be made
-greedy by following them with a question mark. In other words, it inverts the
-default behaviour.
-</P>
-<P>
-When a parenthesized subpattern is quantified with a minimum repeat count that
-is greater than 1 or with a limited maximum, more store is required for the
-compiled pattern, in proportion to the size of the minimum or maximum.
-</P>
-<P>
-If a pattern starts with .* or .{0,} and the PCRE_DOTALL option (equivalent
-to Perl's /s) is set, thus allowing the . to match newlines, the pattern is
-implicitly anchored, because whatever follows will be tried against every
-character position in the subject string, so there is no point in retrying the
-overall match at any position after the first. PCRE treats such a pattern as
-though it were preceded by \A. In cases where it is known that the subject
-string contains no newlines, it is worth setting PCRE_DOTALL when the pattern
-begins with .* in order to obtain this optimization, or alternatively using ^
-to indicate anchoring explicitly.
-</P>
-<P>
-When a capturing subpattern is repeated, the value captured is the substring
-that matched the final iteration. For example, after
-</P>
-<P>
-<PRE>
-  (tweedle[dume]{3}\s*)+
-</PRE>
-</P>
-<P>
-has matched "tweedledum tweedledee" the value of the captured substring is
-"tweedledee". However, if there are nested capturing subpatterns, the
-corresponding captured values may have been set in previous iterations. For
-example, after
-</P>
-<P>
-<PRE>
-  /(a|(b))+/
-</PRE>
-</P>
-<P>
-matches "aba" the value of the second captured substring is "b".
-</P>
-<LI><A NAME="SEC23" HREF="#TOC1">BACK REFERENCES</A>
-<P>
-Outside a character class, a backslash followed by a digit greater than 0 (and
-possibly further digits) is a back reference to a capturing subpattern earlier
-(i.e. to its left) in the pattern, provided there have been that many previous
-capturing left parentheses.
-</P>
-<P>
-However, if the decimal number following the backslash is less than 10, it is
-always taken as a back reference, and causes an error only if there are not
-that many capturing left parentheses in the entire pattern. In other words, the
-parentheses that are referenced need not be to the left of the reference for
-numbers less than 10. See the section entitled "Backslash" above for further
-details of the handling of digits following a backslash.
-</P>
-<P>
-A back reference matches whatever actually matched the capturing subpattern in
-the current subject string, rather than anything matching the subpattern
-itself. So the pattern
-</P>
-<P>
-<PRE>
-  (sens|respons)e and \1ibility
-</PRE>
-</P>
-<P>
-matches "sense and sensibility" and "response and responsibility", but not
-"sense and responsibility". If caseful matching is in force at the time of the
-back reference, the case of letters is relevant. For example,
-</P>
-<P>
-<PRE>
-  ((?i)rah)\s+\1
-</PRE>
-</P>
-<P>
-matches "rah rah" and "RAH RAH", but not "RAH rah", even though the original
-capturing subpattern is matched caselessly.
-</P>
-<P>
-There may be more than one back reference to the same subpattern. If a
-subpattern has not actually been used in a particular match, any back
-references to it always fail. For example, the pattern
-</P>
-<P>
-<PRE>
-  (a|(bc))\2
-</PRE>
-</P>
-<P>
-always fails if it starts to match "a" rather than "bc". Because there may be
-up to 99 back references, all digits following the backslash are taken
-as part of a potential back reference number. If the pattern continues with a
-digit character, some delimiter must be used to terminate the back reference.
-If the PCRE_EXTENDED option is set, this can be whitespace. Otherwise an empty
-comment can be used.
-</P>
-<P>
-A back reference that occurs inside the parentheses to which it refers fails
-when the subpattern is first used, so, for example, (a\1) never matches.
-However, such references can be useful inside repeated subpatterns. For
-example, the pattern
-</P>
-<P>
-<PRE>
-  (a|b\1)+
-</PRE>
-</P>
-<P>
-matches any number of "a"s and also "aba", "ababbaa" etc. At each iteration of
-the subpattern, the back reference matches the character string corresponding
-to the previous iteration. In order for this to work, the pattern must be such
-that the first iteration does not need to match the back reference. This can be
-done using alternation, as in the example above, or by a quantifier with a
-minimum of zero.
-</P>
-<LI><A NAME="SEC24" HREF="#TOC1">ASSERTIONS</A>
-<P>
-An assertion is a test on the characters following or preceding the current
-matching point that does not actually consume any characters. The simple
-assertions coded as \b, \B, \A, \Z, \z, ^ and $ are described above. More
-complicated assertions are coded as subpatterns. There are two kinds: those
-that look ahead of the current position in the subject string, and those that
-look behind it.
-</P>
-<P>
-An assertion subpattern is matched in the normal way, except that it does not
-cause the current matching position to be changed. Lookahead assertions start
-with (?= for positive assertions and (?! for negative assertions. For example,
-</P>
-<P>
-<PRE>
-  \w+(?=;)
-</PRE>
-</P>
-<P>
-matches a word followed by a semicolon, but does not include the semicolon in
-the match, and
-</P>
-<P>
-<PRE>
-  foo(?!bar)
-</PRE>
-</P>
-<P>
-matches any occurrence of "foo" that is not followed by "bar". Note that the
-apparently similar pattern
-</P>
-<P>
-<PRE>
-  (?!foo)bar
-</PRE>
-</P>
-<P>
-does not find an occurrence of "bar" that is preceded by something other than
-"foo"; it finds any occurrence of "bar" whatsoever, because the assertion
-(?!foo) is always true when the next three characters are "bar". A
-lookbehind assertion is needed to achieve this effect.
-</P>
-<P>
-Lookbehind assertions start with (?&#60;= for positive assertions and (?&#60;! for
-negative assertions. For example,
-</P>
-<P>
-<PRE>
-  (?&#60;!foo)bar
-</PRE>
-</P>
-<P>
-does find an occurrence of "bar" that is not preceded by "foo". The contents of
-a lookbehind assertion are restricted such that all the strings it matches must
-have a fixed length. However, if there are several alternatives, they do not
-all have to have the same fixed length. Thus
-</P>
-<P>
-<PRE>
-  (?&#60;=bullock|donkey)
-</PRE>
-</P>
-<P>
-is permitted, but
-</P>
-<P>
-<PRE>
-  (?&#60;!dogs?|cats?)
-</PRE>
-</P>
-<P>
-causes an error at compile time. Branches that match different length strings
-are permitted only at the top level of a lookbehind assertion. This is an
-extension compared with Perl 5.005, which requires all branches to match the
-same length of string. An assertion such as
-</P>
-<P>
-<PRE>
-  (?&#60;=ab(c|de))
-</PRE>
-</P>
-<P>
-is not permitted, because its single top-level branch can match two different
-lengths, but it is acceptable if rewritten to use two top-level branches:
-</P>
-<P>
-<PRE>
-  (?&#60;=abc|abde)
-</PRE>
-</P>
-<P>
-The implementation of lookbehind assertions is, for each alternative, to
-temporarily move the current position back by the fixed width and then try to
-match. If there are insufficient characters before the current position, the
-match is deemed to fail. Lookbehinds in conjunction with once-only subpatterns
-can be particularly useful for matching at the ends of strings; an example is
-given at the end of the section on once-only subpatterns.
-</P>
-<P>
-Several assertions (of any sort) may occur in succession. For example,
-</P>
-<P>
-<PRE>
-  (?&#60;=\d{3})(?&#60;!999)foo
-</PRE>
-</P>
-<P>
-matches "foo" preceded by three digits that are not "999". Notice that each of
-the assertions is applied independently at the same point in the subject
-string. First there is a check that the previous three characters are all
-digits, and then there is a check that the same three characters are not "999".
-This pattern does <I>not</I> match "foo" preceded by six characters, the first
-of which are digits and the last three of which are not "999". For example, it
-doesn't match "123abcfoo". A pattern to do that is
-</P>
-<P>
-<PRE>
-  (?&#60;=\d{3}...)(?&#60;!999)foo
-</PRE>
-</P>
-<P>
-This time the first assertion looks at the preceding six characters, checking
-that the first three are digits, and then the second assertion checks that the
-preceding three characters are not "999".
-</P>
-<P>
-Assertions can be nested in any combination. For example,
-</P>
-<P>
-<PRE>
-  (?&#60;=(?&#60;!foo)bar)baz
-</PRE>
-</P>
-<P>
-matches an occurrence of "baz" that is preceded by "bar" which in turn is not
-preceded by "foo", while
-</P>
-<P>
-<PRE>
-  (?&#60;=\d{3}(?!999)...)foo
-</PRE>
-</P>
-<P>
-is another pattern which matches "foo" preceded by three digits and any three
-characters that are not "999".
-</P>
-<P>
-Assertion subpatterns are not capturing subpatterns, and may not be repeated,
-because it makes no sense to assert the same thing several times. If any kind
-of assertion contains capturing subpatterns within it, these are counted for
-the purposes of numbering the capturing subpatterns in the whole pattern.
-However, substring capturing is carried out only for positive assertions,
-because it does not make sense for negative assertions.
-</P>
-<P>
-Assertions count towards the maximum of 200 parenthesized subpatterns.
-</P>
-<LI><A NAME="SEC25" HREF="#TOC1">ONCE-ONLY SUBPATTERNS</A>
-<P>
-With both maximizing and minimizing repetition, failure of what follows
-normally causes the repeated item to be re-evaluated to see if a different
-number of repeats allows the rest of the pattern to match. Sometimes it is
-useful to prevent this, either to change the nature of the match, or to cause
-it fail earlier than it otherwise might, when the author of the pattern knows
-there is no point in carrying on.
-</P>
-<P>
-Consider, for example, the pattern \d+foo when applied to the subject line
-</P>
-<P>
-<PRE>
-  123456bar
-</PRE>
-</P>
-<P>
-After matching all 6 digits and then failing to match "foo", the normal
-action of the matcher is to try again with only 5 digits matching the \d+
-item, and then with 4, and so on, before ultimately failing. Once-only
-subpatterns provide the means for specifying that once a portion of the pattern
-has matched, it is not to be re-evaluated in this way, so the matcher would
-give up immediately on failing to match "foo" the first time. The notation is
-another kind of special parenthesis, starting with (?&#62; as in this example:
-</P>
-<P>
-<PRE>
-  (?&#62;\d+)bar
-</PRE>
-</P>
-<P>
-This kind of parenthesis "locks up" the  part of the pattern it contains once
-it has matched, and a failure further into the pattern is prevented from
-backtracking into it. Backtracking past it to previous items, however, works as
-normal.
-</P>
-<P>
-An alternative description is that a subpattern of this type matches the string
-of characters that an identical standalone pattern would match, if anchored at
-the current point in the subject string.
-</P>
-<P>
-Once-only subpatterns are not capturing subpatterns. Simple cases such as the
-above example can be thought of as a maximizing repeat that must swallow
-everything it can. So, while both \d+ and \d+? are prepared to adjust the
-number of digits they match in order to make the rest of the pattern match,
-(?&#62;\d+) can only match an entire sequence of digits.
-</P>
-<P>
-This construction can of course contain arbitrarily complicated subpatterns,
-and it can be nested.
-</P>
-<P>
-Once-only subpatterns can be used in conjunction with lookbehind assertions to
-specify efficient matching at the end of the subject string. Consider a simple
-pattern such as
-</P>
-<P>
-<PRE>
-  abcd$
-</PRE>
-</P>
-<P>
-when applied to a long string which does not match. Because matching proceeds
-from left to right, PCRE will look for each "a" in the subject and then see if
-what follows matches the rest of the pattern. If the pattern is specified as
-</P>
-<P>
-<PRE>
-  ^.*abcd$
-</PRE>
-</P>
-<P>
-the initial .* matches the entire string at first, but when this fails (because
-there is no following "a"), it backtracks to match all but the last character,
-then all but the last two characters, and so on. Once again the search for "a"
-covers the entire string, from right to left, so we are no better off. However,
-if the pattern is written as
-</P>
-<P>
-<PRE>
-  ^(?&#62;.*)(?&#60;=abcd)
-</PRE>
-</P>
-<P>
-there can be no backtracking for the .* item; it can match only the entire
-string. The subsequent lookbehind assertion does a single test on the last four
-characters. If it fails, the match fails immediately. For long strings, this
-approach makes a significant difference to the processing time.
-</P>
-<P>
-When a pattern contains an unlimited repeat inside a subpattern that can itself
-be repeated an unlimited number of times, the use of a once-only subpattern is
-the only way to avoid some failing matches taking a very long time indeed.
-The pattern
-</P>
-<P>
-<PRE>
-  (\D+|&#60;\d+&#62;)*[!?]
-</PRE>
-</P>
-<P>
-matches an unlimited number of substrings that either consist of non-digits, or
-digits enclosed in &#60;&#62;, followed by either ! or ?. When it matches, it runs
-quickly. However, if it is applied to
-</P>
-<P>
-<PRE>
-  aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
-</PRE>
-</P>
-<P>
-it takes a long time before reporting failure. This is because the string can
-be divided between the two repeats in a large number of ways, and all have to
-be tried. (The example used [!?] rather than a single character at the end,
-because both PCRE and Perl have an optimization that allows for fast failure
-when a single character is used. They remember the last single character that
-is required for a match, and fail early if it is not present in the string.)
-If the pattern is changed to
-</P>
-<P>
-<PRE>
-  ((?&#62;\D+)|&#60;\d+&#62;)*[!?]
-</PRE>
-</P>
-<P>
-sequences of non-digits cannot be broken, and failure happens quickly.
-</P>
-<LI><A NAME="SEC26" HREF="#TOC1">CONDITIONAL SUBPATTERNS</A>
-<P>
-It is possible to cause the matching process to obey a subpattern
-conditionally or to choose between two alternative subpatterns, depending on
-the result of an assertion, or whether a previous capturing subpattern matched
-or not. The two possible forms of conditional subpattern are
-</P>
-<P>
-<PRE>
-  (?(condition)yes-pattern)
-  (?(condition)yes-pattern|no-pattern)
-</PRE>
-</P>
-<P>
-If the condition is satisfied, the yes-pattern is used; otherwise the
-no-pattern (if present) is used. If there are more than two alternatives in the
-subpattern, a compile-time error occurs.
-</P>
-<P>
-There are two kinds of condition. If the text between the parentheses consists
-of a sequence of digits, the condition is satisfied if the capturing subpattern
-of that number has previously matched. The number must be greater than zero.
-Consider the following pattern, which contains non-significant white space to
-make it more readable (assume the PCRE_EXTENDED option) and to divide it into
-three parts for ease of discussion:
-</P>
-<P>
-<PRE>
-  ( \( )?    [^()]+    (?(1) \) )
-</PRE>
-</P>
-<P>
-The first part matches an optional opening parenthesis, and if that
-character is present, sets it as the first captured substring. The second part
-matches one or more characters that are not parentheses. The third part is a
-conditional subpattern that tests whether the first set of parentheses matched
-or not. If they did, that is, if subject started with an opening parenthesis,
-the condition is true, and so the yes-pattern is executed and a closing
-parenthesis is required. Otherwise, since no-pattern is not present, the
-subpattern matches nothing. In other words, this pattern matches a sequence of
-non-parentheses, optionally enclosed in parentheses.
-</P>
-<P>
-If the condition is not a sequence of digits, it must be an assertion. This may
-be a positive or negative lookahead or lookbehind assertion. Consider this
-pattern, again containing non-significant white space, and with the two
-alternatives on the second line:
-</P>
-<P>
-<PRE>
-  (?(?=[^a-z]*[a-z])
-  \d{2}-[a-z]{3}-\d{2}  |  \d{2}-\d{2}-\d{2} )
-</PRE>
-</P>
-<P>
-The condition is a positive lookahead assertion that matches an optional
-sequence of non-letters followed by a letter. In other words, it tests for the
-presence of at least one letter in the subject. If a letter is found, the
-subject is matched against the first alternative; otherwise it is matched
-against the second. This pattern matches strings in one of the two forms
-dd-aaa-dd or dd-dd-dd, where aaa are letters and dd are digits.
-</P>
-<LI><A NAME="SEC27" HREF="#TOC1">COMMENTS</A>
-<P>
-The sequence (?# marks the start of a comment which continues up to the next
-closing parenthesis. Nested parentheses are not permitted. The characters
-that make up a comment play no part in the pattern matching at all.
-</P>
-<P>
-If the PCRE_EXTENDED option is set, an unescaped # character outside a
-character class introduces a comment that continues up to the next newline
-character in the pattern.
-</P>
-<LI><A NAME="SEC28" HREF="#TOC1">RECURSIVE PATTERNS</A>
-<P>
-Consider the problem of matching a string in parentheses, allowing for
-unlimited nested parentheses. Without the use of recursion, the best that can
-be done is to use a pattern that matches up to some fixed depth of nesting. It
-is not possible to handle an arbitrary nesting depth. Perl 5.6 has provided an
-experimental facility that allows regular expressions to recurse (amongst other
-things). It does this by interpolating Perl code in the expression at run time,
-and the code can refer to the expression itself. A Perl pattern to solve the
-parentheses problem can be created like this:
-</P>
-<P>
-<PRE>
-  $re = qr{\( (?: (?&#62;[^()]+) | (?p{$re}) )* \)}x;
-</PRE>
-</P>
-<P>
-The (?p{...}) item interpolates Perl code at run time, and in this case refers
-recursively to the pattern in which it appears. Obviously, PCRE cannot support
-the interpolation of Perl code. Instead, the special item (?R) is provided for
-the specific case of recursion. This PCRE pattern solves the parentheses
-problem (assume the PCRE_EXTENDED option is set so that white space is
-ignored):
-</P>
-<P>
-<PRE>
-  \( ( (?&#62;[^()]+) | (?R) )* \)
-</PRE>
-</P>
-<P>
-First it matches an opening parenthesis. Then it matches any number of
-substrings which can either be a sequence of non-parentheses, or a recursive
-match of the pattern itself (i.e. a correctly parenthesized substring). Finally
-there is a closing parenthesis.
-</P>
-<P>
-This particular example pattern contains nested unlimited repeats, and so the
-use of a once-only subpattern for matching strings of non-parentheses is
-important when applying the pattern to strings that do not match. For example,
-when it is applied to
-</P>
-<P>
-<PRE>
-  (aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa()
-</PRE>
-</P>
-<P>
-it yields "no match" quickly. However, if a once-only subpattern is not used,
-the match runs for a very long time indeed because there are so many different
-ways the + and * repeats can carve up the subject, and all have to be tested
-before failure can be reported.
-</P>
-<P>
-The values set for any capturing subpatterns are those from the outermost level
-of the recursion at which the subpattern value is set. If the pattern above is
-matched against
-</P>
-<P>
-<PRE>
-  (ab(cd)ef)
-</PRE>
-</P>
-<P>
-the value for the capturing parentheses is "ef", which is the last value taken
-on at the top level. If additional parentheses are added, giving
-</P>
-<P>
-<PRE>
-  \( ( ( (?&#62;[^()]+) | (?R) )* ) \)
-     ^                        ^
-     ^                        ^
-</PRE>
-the string they capture is "ab(cd)ef", the contents of the top level
-parentheses. If there are more than 15 capturing parentheses in a pattern, PCRE
-has to obtain extra memory to store data during a recursion, which it does by
-using <B>pcre_malloc</B>, freeing it via <B>pcre_free</B> afterwards. If no
-memory can be obtained, it saves data for the first 15 capturing parentheses
-only, as there is no way to give an out-of-memory error from within a
-recursion.
-</P>
-<LI><A NAME="SEC29" HREF="#TOC1">PERFORMANCE</A>
-<P>
-Certain items that may appear in patterns are more efficient than others. It is
-more efficient to use a character class like [aeiou] than a set of alternatives
-such as (a|e|i|o|u). In general, the simplest construction that provides the
-required behaviour is usually the most efficient. Jeffrey Friedl's book
-contains a lot of discussion about optimizing regular expressions for efficient
-performance.
-</P>
-<P>
-When a pattern begins with .* and the PCRE_DOTALL option is set, the pattern is
-implicitly anchored by PCRE, since it can match only at the start of a subject
-string. However, if PCRE_DOTALL is not set, PCRE cannot make this optimization,
-because the . metacharacter does not then match a newline, and if the subject
-string contains newlines, the pattern may match from the character immediately
-following one of them instead of from the very start. For example, the pattern
-</P>
-<P>
-<PRE>
-  (.*) second
-</PRE>
-</P>
-<P>
-matches the subject "first\nand second" (where \n stands for a newline
-character) with the first captured substring being "and". In order to do this,
-PCRE has to retry the match starting after every newline in the subject.
-</P>
-<P>
-If you are using such a pattern with subject strings that do not contain
-newlines, the best performance is obtained by setting PCRE_DOTALL, or starting
-the pattern with ^.* to indicate explicit anchoring. That saves PCRE from
-having to scan along the subject looking for a newline to restart at.
-</P>
-<P>
-Beware of patterns that contain nested indefinite repeats. These can take a
-long time to run when applied to a string that does not match. Consider the
-pattern fragment
-</P>
-<P>
-<PRE>
-  (a+)*
-</PRE>
-</P>
-<P>
-This can match "aaaa" in 33 different ways, and this number increases very
-rapidly as the string gets longer. (The * repeat can match 0, 1, 2, 3, or 4
-times, and for each of those cases other than 0, the + repeats can match
-different numbers of times.) When the remainder of the pattern is such that the
-entire match is going to fail, PCRE has in principle to try every possible
-variation, and this can take an extremely long time.
-</P>
-<P>
-An optimization catches some of the more simple cases such as
-</P>
-<P>
-<PRE>
-  (a+)*b
-</PRE>
-</P>
-<P>
-where a literal character follows. Before embarking on the standard matching
-procedure, PCRE checks that there is a "b" later in the subject string, and if
-there is not, it fails the match immediately. However, when there is no
-following literal this optimization cannot be used. You can see the difference
-by comparing the behaviour of
-</P>
-<P>
-<PRE>
-  (a+)*\d
-</PRE>
-</P>
-<P>
-with the pattern above. The former gives a failure almost instantly when
-applied to a whole line of "a" characters, whereas the latter takes an
-appreciable time with strings longer than about 20 characters.
-</P>
-<LI><A NAME="SEC30" HREF="#TOC1">UTF-8 SUPPORT</A>
-<P>
-Starting at release 3.3, PCRE has some support for character strings encoded
-in the UTF-8 format. This is incomplete, and is regarded as experimental. In
-order to use it, you must configure PCRE to include UTF-8 support in the code,
-and, in addition, you must call <B>pcre_compile()</B> with the PCRE_UTF8 option
-flag. When you do this, both the pattern and any subject strings that are
-matched against it are treated as UTF-8 strings instead of just strings of
-bytes, but only in the cases that are mentioned below.
-</P>
-<P>
-If you compile PCRE with UTF-8 support, but do not use it at run time, the
-library will be a bit bigger, but the additional run time overhead is limited
-to testing the PCRE_UTF8 flag in several places, so should not be very large.
-</P>
-<P>
-PCRE assumes that the strings it is given contain valid UTF-8 codes. It does
-not diagnose invalid UTF-8 strings. If you pass invalid UTF-8 strings to PCRE,
-the results are undefined.
-</P>
-<P>
-Running with PCRE_UTF8 set causes these changes in the way PCRE works:
-</P>
-<P>
-1. In a pattern, the escape sequence \x{...}, where the contents of the braces
-is a string of hexadecimal digits, is interpreted as a UTF-8 character whose
-code number is the given hexadecimal number, for example: \x{1234}. This
-inserts from one to six literal bytes into the pattern, using the UTF-8
-encoding. If a non-hexadecimal digit appears between the braces, the item is
-not recognized.
-</P>
-<P>
-2. The original hexadecimal escape sequence, \xhh, generates a two-byte UTF-8
-character if its value is greater than 127.
-</P>
-<P>
-3. Repeat quantifiers are NOT correctly handled if they follow a multibyte
-character. For example, \x{100}* and \xc3+ do not work. If you want to
-repeat such characters, you must enclose them in non-capturing parentheses,
-for example (?:\x{100}), at present.
-</P>
-<P>
-4. The dot metacharacter matches one UTF-8 character instead of a single byte.
-</P>
-<P>
-5. Unlike literal UTF-8 characters, the dot metacharacter followed by a
-repeat quantifier does operate correctly on UTF-8 characters instead of
-single bytes.
-</P>
-<P>
-4. Although the \x{...} escape is permitted in a character class, characters
-whose values are greater than 255 cannot be included in a class.
-</P>
-<P>
-5. A class is matched against a UTF-8 character instead of just a single byte,
-but it can match only characters whose values are less than 256. Characters
-with greater values always fail to match a class.
-</P>
-<P>
-6. Repeated classes work correctly on multiple characters.
-</P>
-<P>
-7. Classes containing just a single character whose value is greater than 127
-(but less than 256), for example, [\x80] or [^\x{93}], do not work because
-these are optimized into single byte matches. In the first case, of course,
-the class brackets are just redundant.
-</P>
-<P>
-8. Lookbehind assertions move backwards in the subject by a fixed number of
-characters instead of a fixed number of bytes. Simple cases have been tested
-to work correctly, but there may be hidden gotchas herein.
-</P>
-<P>
-9. The character types such as \d and \w do not work correctly with UTF-8
-characters. They continue to test a single byte.
-</P>
-<P>
-10. Anything not explicitly mentioned here continues to work in bytes rather
-than in characters.
-</P>
-<P>
-The following UTF-8 features of Perl 5.6 are not implemented:
-</P>
-<P>
-1. The escape sequence \C to match a single byte.
-</P>
-<P>
-2. The use of Unicode tables and properties and escapes \p, \P, and \X.
-</P>
-<LI><A NAME="SEC31" HREF="#TOC1">AUTHOR</A>
-<P>
-Philip Hazel &#60;ph10@cam.ac.uk&#62;
-<BR>
-University Computing Service,
-<BR>
-New Museums Site,
-<BR>
-Cambridge CB2 3QG, England.
-<BR>
-Phone: +44 1223 334714
-</P>
-<P>
-Last updated: 28 August 2000,
-<BR>
-<PRE>
-  the 250th anniversary of the death of J.S. Bach.
-<BR>
-</PRE>
-Copyright (c) 1997-2000 University of Cambridge.
diff --git a/ext/pcre/pcrelib/doc/pcre.txt b/ext/pcre/pcrelib/doc/pcre.txt
deleted file mode 100644
index 1db4b537b7..0000000000
--- a/ext/pcre/pcrelib/doc/pcre.txt
+++ /dev/null
@@ -1,2125 +0,0 @@
-NAME
-     pcre - Perl-compatible regular expressions.
-
-
-
-SYNOPSIS
-     #include <pcre.h>
-
-     pcre *pcre_compile(const char *pattern, int options,
-          const char **errptr, int *erroffset,
-          const unsigned char *tableptr);
-
-     pcre_extra *pcre_study(const pcre *code, int options,
-          const char **errptr);
-
-     int pcre_exec(const pcre *code, const pcre_extra *extra,
-          const char *subject, int length, int startoffset,
-          int options, int *ovector, int ovecsize);
-
-     int pcre_copy_substring(const char *subject, int *ovector,
-          int stringcount, int stringnumber, char *buffer,
-          int buffersize);
-
-     int pcre_get_substring(const char *subject, int *ovector,
-          int stringcount, int stringnumber,
-          const char **stringptr);
-
-     int pcre_get_substring_list(const char *subject,
-          int *ovector, int stringcount, const char ***listptr);
-
-     void pcre_free_substring(const char *stringptr);
-
-     void pcre_free_substring_list(const char **stringptr);
-
-     const unsigned char *pcre_maketables(void);
-
-     int pcre_fullinfo(const pcre *code, const pcre_extra *extra,
-          int what, void *where);
-
-     int pcre_info(const pcre *code, int *optptr, *firstcharptr);
-
-     char *pcre_version(void);
-
-     void *(*pcre_malloc)(size_t);
-
-     void (*pcre_free)(void *);
-
-
-
-
-DESCRIPTION
-     The PCRE library is a set of functions that implement  regu-
-     lar  expression  pattern  matching using the same syntax and
-     semantics as Perl  5,  with  just  a  few  differences  (see
-
-     below).  The  current  implementation  corresponds  to  Perl
-     5.005, with some additional features  from  later  versions.
-     This  includes  some  experimental,  incomplete  support for
-     UTF-8 encoded strings. Details of exactly what is  and  what
-     is not supported are given below.
-
-     PCRE has its own native API,  which  is  described  in  this
-     document.  There  is  also  a  set of wrapper functions that
-     correspond to the POSIX regular expression API.   These  are
-     described in the pcreposix documentation.
-
-     The native API function prototypes are defined in the header
-     file  pcre.h,  and  on  Unix  systems  the library itself is
-     called libpcre.a, so can be accessed by adding -lpcre to the
-     command  for  linking  an  application  which  calls it. The
-     header file defines the macros PCRE_MAJOR and PCRE_MINOR  to
-     contain the major and minor release numbers for the library.
-     Applications can use these to include support for  different
-     releases.
-
-     The functions pcre_compile(), pcre_study(), and  pcre_exec()
-     are used for compiling and matching regular expressions.
-
-     The functions  pcre_copy_substring(),  pcre_get_substring(),
-     and  pcre_get_substring_list() are convenience functions for
-     extracting  captured  substrings  from  a  matched   subject
-     string; pcre_free_substring() and pcre_free_substring_list()
-     are also provided, to free the  memory  used  for  extracted
-     strings.
-
-     The function pcre_maketables() is used (optionally) to build
-     a  set of character tables in the current locale for passing
-     to pcre_compile().
-
-     The function pcre_fullinfo() is used to find out information
-     about a compiled pattern; pcre_info() is an obsolete version
-     which returns only some of the available information, but is
-     retained   for   backwards   compatibility.    The  function
-     pcre_version() returns a pointer to a string containing  the
-     version of PCRE and its date of release.
-
-     The global variables  pcre_malloc  and  pcre_free  initially
-     contain the entry points of the standard malloc() and free()
-     functions respectively. PCRE  calls  the  memory  management
-     functions  via  these  variables,  so  a calling program can
-     replace them if it  wishes  to  intercept  the  calls.  This
-     should be done before calling any PCRE functions.
-
-
-
-MULTI-THREADING
-     The  PCRE  functions  can   be   used   in   multi-threading
-
-
-
-
-
-SunOS 5.8                 Last change:                          2
-
-
-
-     applications,  with  the  proviso that the memory management
-     functions pointed to by pcre_malloc and pcre_free are shared
-     by all threads.
-
-     The compiled form of a regular  expression  is  not  altered
-     during  matching, so the same compiled pattern can safely be
-     used by several threads at once.
-
-
-
-COMPILING A PATTERN
-     The function pcre_compile() is called to compile  a  pattern
-     into  an internal form. The pattern is a C string terminated
-     by a binary zero, and is passed in the argument  pattern.  A
-     pointer  to  a  single  block of memory that is obtained via
-     pcre_malloc is returned. This contains the compiled code and
-     related data. The pcre type is defined for this for conveni-
-     ence, but in fact pcre is just a typedef for void, since the
-     contents  of  the block are not externally defined. It is up
-     to the caller to free  the  memory  when  it  is  no  longer
-     required.
-
-     The size of a compiled pattern is  roughly  proportional  to
-     the length of the pattern string, except that each character
-     class (other than those containing just a single  character,
-     negated  or  not)  requires 33 bytes, and repeat quantifiers
-     with a minimum greater than one or a bounded  maximum  cause
-     the  relevant  portions of the compiled pattern to be repli-
-     cated.
-
-     The options argument contains independent bits  that  affect
-     the  compilation.  It  should  be  zero  if  no  options are
-     required. Some of the options, in particular, those that are
-     compatible  with Perl, can also be set and unset from within
-     the pattern (see the detailed description of regular expres-
-     sions below). For these options, the contents of the options
-     argument specifies their initial settings at  the  start  of
-     compilation  and  execution. The PCRE_ANCHORED option can be
-     set at the time of matching as well as at compile time.
-
-     If errptr is NULL, pcre_compile() returns NULL  immediately.
-     Otherwise, if compilation of a pattern fails, pcre_compile()
-     returns NULL, and sets the variable pointed to by errptr  to
-     point  to a textual error message. The offset from the start
-     of  the  pattern  to  the  character  where  the  error  was
-     discovered   is   placed  in  the  variable  pointed  to  by
-     erroffset, which must not be NULL. If it  is,  an  immediate
-     error is given.
-
-     If the final  argument,  tableptr,  is  NULL,  PCRE  uses  a
-     default  set  of character tables which are built when it is
-     compiled, using the default C  locale.  Otherwise,  tableptr
-     must  be  the result of a call to pcre_maketables(). See the
-     section on locale support below.
-
-     The following option bits are defined in the header file:
-
-       PCRE_ANCHORED
-
-     If this bit is set, the pattern is forced to be  "anchored",
-     that is, it is constrained to match only at the start of the
-     string which is being searched (the "subject string").  This
-     effect can also be achieved by appropriate constructs in the
-     pattern itself, which is the only way to do it in Perl.
-
-       PCRE_CASELESS
-
-     If this bit is set, letters in the pattern match both  upper
-     and  lower  case  letters.  It  is  equivalent  to Perl's /i
-     option.
-
-       PCRE_DOLLAR_ENDONLY
-
-     If this bit is set, a dollar metacharacter  in  the  pattern
-     matches  only at the end of the subject string. Without this
-     option, a dollar also matches immediately before  the  final
-     character  if it is a newline (but not before any other new-
-     lines).  The  PCRE_DOLLAR_ENDONLY  option  is   ignored   if
-     PCRE_MULTILINE is set. There is no equivalent to this option
-     in Perl.
-
-       PCRE_DOTALL
-
-     If this bit is  set,  a  dot  metacharater  in  the  pattern
-     matches all characters, including newlines. Without it, new-
-     lines are excluded. This option is equivalent to  Perl's  /s
-     option.  A negative class such as [^a] always matches a new-
-     line character, independent of the setting of this option.
-
-       PCRE_EXTENDED
-
-     If this bit is set, whitespace data characters in  the  pat-
-     tern  are  totally  ignored  except when escaped or inside a
-     character class, and characters between an unescaped #  out-
-     side  a  character  class  and  the  next newline character,
-     inclusive, are also ignored. This is equivalent to Perl's /x
-     option,  and  makes  it  possible to include comments inside
-     complicated patterns. Note, however, that this applies  only
-     to  data  characters. Whitespace characters may never appear
-     within special character sequences in a pattern, for example
-     within  the sequence (?( which introduces a conditional sub-
-     pattern.
-
-       PCRE_EXTRA
-
-     This option was invented in  order  to  turn  on  additional
-     functionality of PCRE that is incompatible with Perl, but it
-     is currently of very little use. When set, any backslash  in
-     a  pattern  that is followed by a letter that has no special
-     meaning causes an error, thus reserving  these  combinations
-     for  future  expansion.  By default, as in Perl, a backslash
-     followed by a letter with no special meaning is treated as a
-     literal.  There  are at present no other features controlled
-     by this option. It can also be set by a (?X) option  setting
-     within a pattern.
-
-       PCRE_MULTILINE
-
-     By default, PCRE treats the subject string as consisting  of
-     a  single "line" of characters (even if it actually contains
-     several newlines). The "start  of  line"  metacharacter  (^)
-     matches  only  at the start of the string, while the "end of
-     line" metacharacter ($) matches  only  at  the  end  of  the
-     string,    or   before   a   terminating   newline   (unless
-     PCRE_DOLLAR_ENDONLY is set). This is the same as Perl.
-
-     When PCRE_MULTILINE it is set, the "start of line" and  "end
-     of  line"  constructs match immediately following or immedi-
-     ately before any newline  in  the  subject  string,  respec-
-     tively,  as  well  as  at  the  very  start and end. This is
-     equivalent to Perl's /m option. If there are no "\n" charac-
-     ters  in  a subject string, or no occurrences of ^ or $ in a
-     pattern, setting PCRE_MULTILINE has no effect.
-
-       PCRE_UNGREEDY
-
-     This option inverts the "greediness" of the  quantifiers  so
-     that  they  are  not greedy by default, but become greedy if
-     followed by "?". It is not compatible with Perl. It can also
-     be set by a (?U) option setting within the pattern.
-
-       PCRE_UTF8
-
-     This option causes PCRE to regard both the pattern  and  the
-     subject  as strings of UTF-8 characters instead of just byte
-     strings. However, it is available  only  if  PCRE  has  been
-     built  to  include  UTF-8  support.  If not, the use of this
-     option provokes an error. Support for UTF-8 is new,  experi-
-     mental,  and incomplete.  Details of exactly what it entails
-     are given below.
-
-
-
-STUDYING A PATTERN
-     When a pattern is going to be  used  several  times,  it  is
-     worth  spending  more time analyzing it in order to speed up
-     the time taken for matching. The function pcre_study() takes
-
-     a  pointer  to a compiled pattern as its first argument, and
-     returns a  pointer  to  a  pcre_extra  block  (another  void
-     typedef)  containing  additional  information about the pat-
-     tern; this can be passed to pcre_exec().  If  no  additional
-     information is available, NULL is returned.
-
-     The second argument contains option  bits.  At  present,  no
-     options  are  defined  for  pcre_study(),  and this argument
-     should always be zero.
-
-     The third argument for pcre_study() is a pointer to an error
-     message. If studying succeeds (even if no data is returned),
-     the variable it points to  is  set  to  NULL.  Otherwise  it
-     points to a textual error message.
-
-     At present, studying a  pattern  is  useful  only  for  non-
-     anchored  patterns  that do not have a single fixed starting
-     character. A  bitmap  of  possible  starting  characters  is
-     created.
-
-
-
-LOCALE SUPPORT
-     PCRE handles caseless matching, and determines whether char-
-     acters  are  letters, digits, or whatever, by reference to a
-     set of tables. The library contains a default set of  tables
-     which  is  created in the default C locale when PCRE is com-
-     piled.  This  is   used   when   the   final   argument   of
-     pcre_compile()  is NULL, and is sufficient for many applica-
-     tions.
-
-     An alternative set of tables can, however, be supplied. Such
-     tables  are built by calling the pcre_maketables() function,
-     which has no arguments, in the relevant locale.  The  result
-     can  then be passed to pcre_compile() as often as necessary.
-     For example, to build and use tables  that  are  appropriate
-     for  the French locale (where accented characters with codes
-     greater than 128 are treated as letters), the following code
-     could be used:
-
-       setlocale(LC_CTYPE, "fr");
-       tables = pcre_maketables();
-       re = pcre_compile(..., tables);
-
-     The  tables  are  built  in  memory  that  is  obtained  via
-     pcre_malloc.  The  pointer that is passed to pcre_compile is
-     saved with the compiled pattern, and  the  same  tables  are
-     used  via this pointer by pcre_study() and pcre_exec(). Thus
-     for any single pattern, compilation, studying  and  matching
-     all happen in the same locale, but different patterns can be
-     compiled in different locales. It is the caller's  responsi-
-     bility  to  ensure  that  the  memory  containing the tables
-     remains available for as long as it is needed.
-
-
-
-INFORMATION ABOUT A PATTERN
-     The pcre_fullinfo() function  returns  information  about  a
-     compiled pattern. It replaces the obsolete pcre_info() func-
-     tion, which is nevertheless retained for backwards compabil-
-     ity (and is documented below).
-
-     The first argument for pcre_fullinfo() is a pointer  to  the
-     compiled  pattern.  The  second  argument  is  the result of
-     pcre_study(), or NULL if the pattern was  not  studied.  The
-     third  argument  specifies  which  piece  of  information is
-     required, while the fourth argument is a pointer to a  vari-
-     able  to receive the data. The yield of the function is zero
-     for success, or one of the following negative numbers:
-
-       PCRE_ERROR_NULL       the argument code was NULL
-                             the argument where was NULL
-       PCRE_ERROR_BADMAGIC   the "magic number" was not found
-       PCRE_ERROR_BADOPTION  the value of what was invalid
-
-     The possible values for the third argument  are  defined  in
-     pcre.h, and are as follows:
-
-       PCRE_INFO_OPTIONS
-
-     Return a copy of the options with which the pattern was com-
-     piled.  The fourth argument should point to au unsigned long
-     int variable. These option bits are those specified  in  the
-     call  to  pcre_compile(),  modified  by any top-level option
-     settings  within  the   pattern   itself,   and   with   the
-     PCRE_ANCHORED  bit  forcibly  set if the form of the pattern
-     implies that it can match only at the  start  of  a  subject
-     string.
-
-       PCRE_INFO_SIZE
-
-     Return the size of the compiled pattern, that is, the  value
-     that  was  passed as the argument to pcre_malloc() when PCRE
-     was getting memory in which to place the compiled data.  The
-     fourth argument should point to a size_t variable.
-
-       PCRE_INFO_CAPTURECOUNT
-
-     Return the number of capturing subpatterns in  the  pattern.
-     The fourth argument should point to an int variable.
-
-       PCRE_INFO_BACKREFMAX
-
-     Return the number of  the  highest  back  reference  in  the
-     pattern.  The  fourth  argument should point to an int vari-
-     able. Zero is returned if there are no back references.
-
-       PCRE_INFO_FIRSTCHAR
-
-     Return information about the first character of any  matched
-     string,  for  a  non-anchored  pattern.  If there is a fixed
-     first   character,   e.g.   from   a   pattern    such    as
-     (cat|cow|coyote),  it  is returned in the integer pointed to
-     by where. Otherwise, if either
-
-     (a) the pattern was compiled with the PCRE_MULTILINE option,
-     and every branch starts with "^", or
-
-     (b) every  branch  of  the  pattern  starts  with  ".*"  and
-     PCRE_DOTALL is not set (if it were set, the pattern would be
-     anchored),
-
-     -1 is returned, indicating that the pattern matches only  at
-     the  start  of a subject string or after any "\n" within the
-     string. Otherwise -2 is returned.  For anchored patterns, -2
-     is returned.
-
-       PCRE_INFO_FIRSTTABLE
-
-     If the pattern was studied, and this resulted  in  the  con-
-     struction of a 256-bit table indicating a fixed set of char-
-     acters for the first character in  any  matching  string,  a
-     pointer   to  the  table  is  returned.  Otherwise  NULL  is
-     returned. The fourth argument should point  to  an  unsigned
-     char * variable.
-
-       PCRE_INFO_LASTLITERAL
-
-     For a non-anchored pattern, return the value of  the  right-
-     most  literal  character  which  must  exist  in any matched
-     string, other than at its start. The fourth argument  should
-     point  to an int variable. If there is no such character, or
-     if the pattern is anchored, -1 is returned. For example, for
-     the pattern /a\d+z\d+/ the returned value is 'z'.
-
-     The pcre_info() function is now obsolete because its  inter-
-     face  is  too  restrictive  to return all the available data
-     about  a  compiled  pattern.   New   programs   should   use
-     pcre_fullinfo()  instead.  The  yield  of pcre_info() is the
-     number of capturing subpatterns, or  one  of  the  following
-     negative numbers:
-
-       PCRE_ERROR_NULL       the argument code was NULL
-       PCRE_ERROR_BADMAGIC   the "magic number" was not found
-
-     If the optptr argument is not NULL, a copy  of  the  options
-     with which the pattern was compiled is placed in the integer
-     it points to (see PCRE_INFO_OPTIONS above).
-
-     If the pattern is not anchored and the firstcharptr argument
-     is  not  NULL, it is used to pass back information about the
-     first    character    of    any    matched    string    (see
-     PCRE_INFO_FIRSTCHAR above).
-
-
-
-MATCHING A PATTERN
-     The function pcre_exec() is called to match a subject string
-     against  a pre-compiled pattern, which is passed in the code
-     argument. If the pattern has been studied, the result of the
-     study should be passed in the extra argument. Otherwise this
-     must be NULL.
-
-     The PCRE_ANCHORED option can be passed in the options  argu-
-     ment,  whose unused bits must be zero. However, if a pattern
-     was  compiled  with  PCRE_ANCHORED,  or  turned  out  to  be
-     anchored  by  virtue  of  its  contents,  it  cannot be made
-     unachored at matching time.
-
-     There are also three further options that can be set only at
-     matching time:
-
-       PCRE_NOTBOL
-
-     The first character of the string is not the beginning of  a
-     line,  so  the  circumflex  metacharacter  should  not match
-     before it. Setting this without PCRE_MULTILINE  (at  compile
-     time) causes circumflex never to match.
-
-       PCRE_NOTEOL
-
-     The end of the string is not the end of a line, so the  dol-
-     lar  metacharacter should not match it nor (except in multi-
-     line mode) a newline immediately  before  it.  Setting  this
-     without PCRE_MULTILINE (at compile time) causes dollar never
-     to match.
-
-       PCRE_NOTEMPTY
-
-     An empty string is not considered to be  a  valid  match  if
-     this  option  is  set. If there are alternatives in the pat-
-     tern, they are tried. If  all  the  alternatives  match  the
-     empty  string,  the  entire match fails. For example, if the
-     pattern
-
-       a?b?
-
-     is applied to a string not beginning with  "a"  or  "b",  it
-     matches  the  empty string at the start of the subject. With
-     PCRE_NOTEMPTY set, this match is not valid, so PCRE searches
-     further into the string for occurrences of "a" or "b".
-
-     Perl has no direct equivalent of PCRE_NOTEMPTY, but it  does
-     make  a  special case of a pattern match of the empty string
-     within its split() function, and when using the /g modifier.
-     It  is possible to emulate Perl's behaviour after matching a
-     null string by first trying the  match  again  at  the  same
-     offset  with  PCRE_NOTEMPTY  set,  and then if that fails by
-     advancing the starting offset  (see  below)  and  trying  an
-     ordinary match again.
-
-     The subject string is passed as  a  pointer  in  subject,  a
-     length  in  length,  and  a  starting offset in startoffset.
-     Unlike the pattern string, it may contain binary zero  char-
-     acters.  When  the starting offset is zero, the search for a
-     match starts at the beginning of the subject, and this is by
-     far the most common case.
-
-     A non-zero starting offset  is  useful  when  searching  for
-     another  match  in  the  same subject by calling pcre_exec()
-     again after a previous success.  Setting startoffset differs
-     from  just  passing  over  a  shortened  string  and setting
-     PCRE_NOTBOL in the case of a pattern that  begins  with  any
-     kind of lookbehind. For example, consider the pattern
-
-       \Biss\B
-
-     which finds occurrences of "iss" in the middle of words. (\B
-     matches only if the current position in the subject is not a
-     word boundary.) When applied to the string "Mississipi"  the
-     first  call  to  pcre_exec()  finds the first occurrence. If
-     pcre_exec() is called again with just the remainder  of  the
-     subject,  namely  "issipi", it does not match, because \B is
-     always false at the start of the subject, which is deemed to
-     be  a  word  boundary. However, if pcre_exec() is passed the
-     entire string again, but with startoffset set to 4, it finds
-     the  second  occurrence  of "iss" because it is able to look
-     behind the starting point to discover that it is preceded by
-     a letter.
-
-     If a non-zero starting offset is passed when the pattern  is
-     anchored, one attempt to match at the given offset is tried.
-     This can only succeed if the pattern does  not  require  the
-     match to be at the start of the subject.
-
-     In general, a pattern matches a certain portion of the  sub-
-     ject,  and  in addition, further substrings from the subject
-     may be picked out by parts of  the  pattern.  Following  the
-     usage  in  Jeffrey Friedl's book, this is called "capturing"
-     in what follows, and the phrase  "capturing  subpattern"  is
-     used for a fragment of a pattern that picks out a substring.
-     PCRE supports several other kinds of  parenthesized  subpat-
-     tern that do not cause substrings to be captured.
-
-     Captured substrings are returned to the caller via a  vector
-     of  integer  offsets whose address is passed in ovector. The
-     number of elements in the vector is passed in ovecsize.  The
-     first two-thirds of the vector is used to pass back captured
-     substrings, each substring using a  pair  of  integers.  The
-     remaining  third  of  the  vector  is  used  as workspace by
-     pcre_exec() while matching capturing subpatterns, and is not
-     available for passing back information. The length passed in
-     ovecsize should always be a multiple of three. If it is not,
-     it is rounded down.
-
-     When a match has been successful, information about captured
-     substrings is returned in pairs of integers, starting at the
-     beginning of ovector, and continuing up to two-thirds of its
-     length  at  the  most. The first element of a pair is set to
-     the offset of the first character in a  substring,  and  the
-     second is set to the offset of the first character after the
-     end of a substring. The first  pair,  ovector[0]  and  ovec-
-     tor[1],  identify  the portion of the subject string matched
-     by the entire pattern. The next pair is used for  the  first
-     capturing  subpattern,  and  so  on.  The  value returned by
-     pcre_exec() is the number of pairs that have  been  set.  If
-     there  are no capturing subpatterns, the return value from a
-     successful match is 1, indicating that just the  first  pair
-     of offsets has been set.
-
-     Some convenience functions are provided for  extracting  the
-     captured substrings as separate strings. These are described
-     in the following section.
-
-     It is possible for an capturing  subpattern  number  n+1  to
-     match  some  part  of  the subject when subpattern n has not
-     been used at all.  For  example,  if  the  string  "abc"  is
-     matched  against the pattern (a|(z))(bc) subpatterns 1 and 3
-     are matched, but 2 is not. When this  happens,  both  offset
-     values corresponding to the unused subpattern are set to -1.
-
-     If a capturing subpattern is matched repeatedly, it  is  the
-     last  portion  of  the  string  that  it  matched  that gets
-     returned.
-
-     If the vector is too small to hold  all  the  captured  sub-
-     strings,  it is used as far as possible (up to two-thirds of
-     its length), and the function returns a value  of  zero.  In
-     particular,  if  the  substring offsets are not of interest,
-     pcre_exec() may be called with ovector passed  as  NULL  and
-     ovecsize  as  zero.  However,  if  the pattern contains back
-     references and the ovector isn't big enough to remember  the
-     related  substrings,  PCRE  has to get additional memory for
-     use during matching. Thus it is usually advisable to  supply
-     an ovector.
-
-     Note that pcre_info() can be used to find out how many  cap-
-     turing  subpatterns  there  are  in  a compiled pattern. The
-     smallest size for ovector that will  allow  for  n  captured
-     substrings  in  addition  to  the  offsets  of the substring
-     matched by the whole pattern is (n+1)*3.
-
-     If pcre_exec() fails, it returns a negative number. The fol-
-     lowing are defined in the header file:
-
-       PCRE_ERROR_NOMATCH        (-1)
-
-     The subject string did not match the pattern.
-
-       PCRE_ERROR_NULL           (-2)
-
-     Either code or subject was passed as NULL,  or  ovector  was
-     NULL and ovecsize was not zero.
-
-       PCRE_ERROR_BADOPTION      (-3)
-
-     An unrecognized bit was set in the options argument.
-
-       PCRE_ERROR_BADMAGIC       (-4)
-
-     PCRE stores a 4-byte "magic number" at the start of the com-
-     piled  code,  to  catch  the  case  when it is passed a junk
-     pointer. This is the error it gives when  the  magic  number
-     isn't present.
-
-       PCRE_ERROR_UNKNOWN_NODE   (-5)
-
-     While running the pattern match, an unknown item was encoun-
-     tered in the compiled pattern. This error could be caused by
-     a bug in PCRE or by overwriting of the compiled pattern.
-
-       PCRE_ERROR_NOMEMORY       (-6)
-
-     If a pattern contains back references, but the ovector  that
-     is  passed  to pcre_exec() is not big enough to remember the
-     referenced substrings, PCRE gets a block of  memory  at  the
-     start  of  matching to use for this purpose. If the call via
-     pcre_malloc() fails, this error  is  given.  The  memory  is
-     freed at the end of matching.
-
-
-
-EXTRACTING CAPTURED SUBSTRINGS
-     Captured substrings can be accessed directly  by  using  the
-
-
-
-
-
-SunOS 5.8                 Last change:                         12
-
-
-
-     offsets returned by pcre_exec() in ovector. For convenience,
-     the functions  pcre_copy_substring(),  pcre_get_substring(),
-     and  pcre_get_substring_list()  are  provided for extracting
-     captured  substrings  as  new,   separate,   zero-terminated
-     strings.   A  substring  that  contains  a  binary  zero  is
-     correctly extracted and has a further zero added on the end,
-     but the result does not, of course, function as a C string.
-
-     The first three arguments are the same for all  three  func-
-     tions:  subject  is  the  subject string which has just been
-     successfully matched, ovector is a pointer to the vector  of
-     integer   offsets   that  was  passed  to  pcre_exec(),  and
-     stringcount is the number of substrings that  were  captured
-     by  the  match,  including  the  substring  that matched the
-     entire regular expression. This is  the  value  returned  by
-     pcre_exec  if  it  is  greater  than  zero.  If  pcre_exec()
-     returned zero, indicating that it ran out of space in  ovec-
-     tor,  the  value passed as stringcount should be the size of
-     the vector divided by three.
-
-     The functions pcre_copy_substring() and pcre_get_substring()
-     extract a single substring, whose number is given as string-
-     number. A value of zero extracts the substring that  matched
-     the entire pattern, while higher values extract the captured
-     substrings. For pcre_copy_substring(), the string is  placed
-     in  buffer,  whose  length is given by buffersize, while for
-     pcre_get_substring() a new block of memory is  obtained  via
-     pcre_malloc,  and its address is returned via stringptr. The
-     yield of the function is  the  length  of  the  string,  not
-     including the terminating zero, or one of
-
-       PCRE_ERROR_NOMEMORY       (-6)
-
-     The buffer was too small for pcre_copy_substring(),  or  the
-     attempt to get memory failed for pcre_get_substring().
-
-       PCRE_ERROR_NOSUBSTRING    (-7)
-
-     There is no substring whose number is stringnumber.
-
-     The pcre_get_substring_list() function extracts  all  avail-
-     able  substrings  and builds a list of pointers to them. All
-     this is done in a single block of memory which  is  obtained
-     via pcre_malloc. The address of the memory block is returned
-     via listptr, which is also the start of the list  of  string
-     pointers.  The  end of the list is marked by a NULL pointer.
-     The yield of the function is zero if all went well, or
-
-       PCRE_ERROR_NOMEMORY       (-6)
-
-     if the attempt to get the memory block failed.
-
-     When any of these functions encounter a  substring  that  is
-     unset, which can happen when capturing subpattern number n+1
-     matches some part of the subject, but subpattern n  has  not
-     been  used  at all, they return an empty string. This can be
-     distinguished  from  a  genuine  zero-length  substring   by
-     inspecting the appropriate offset in ovector, which is nega-
-     tive for unset substrings.
-
-     The  two  convenience  functions  pcre_free_substring()  and
-     pcre_free_substring_list()  can  be  used to free the memory
-     returned by  a  previous  call  of  pcre_get_substring()  or
-     pcre_get_substring_list(),  respectively.  They  do  nothing
-     more than call the function pointed to by  pcre_free,  which
-     of  course  could  be called directly from a C program. How-
-     ever, PCRE is used in some situations where it is linked via
-     a  special  interface  to another programming language which
-     cannot use pcre_free directly; it is for  these  cases  that
-     the functions are provided.
-
-
-
-LIMITATIONS
-     There are some size limitations in PCRE but it is hoped that
-     they will never in practice be relevant.  The maximum length
-     of a compiled pattern is 65539 (sic) bytes.  All  values  in
-     repeating  quantifiers must be less than 65536.  The maximum
-     number of capturing subpatterns is 99.  The  maximum  number
-     of  all  parenthesized subpatterns, including capturing sub-
-     patterns, assertions, and other types of subpattern, is 200.
-
-     The maximum length of a subject string is the largest  posi-
-     tive number that an integer variable can hold. However, PCRE
-     uses recursion to handle subpatterns and indefinite  repeti-
-     tion.  This  means  that the available stack space may limit
-     the size of a subject string that can be processed  by  cer-
-     tain patterns.
-
-
-
-DIFFERENCES FROM PERL
-     The differences described here  are  with  respect  to  Perl
-     5.005.
-
-     1. By default, a whitespace character is any character  that
-     the  C  library  function isspace() recognizes, though it is
-     possible to compile PCRE  with  alternative  character  type
-     tables. Normally isspace() matches space, formfeed, newline,
-     carriage return, horizontal tab, and vertical tab. Perl 5 no
-     longer  includes vertical tab in its set of whitespace char-
-     acters. The \v escape that was in the Perl documentation for
-     a long time was never in fact recognized. However, the char-
-     acter itself was treated as whitespace at least up to 5.002.
-     In 5.004 and 5.005 it does not match \s.
-
-     2. PCRE does  not  allow  repeat  quantifiers  on  lookahead
-     assertions. Perl permits them, but they do not mean what you
-     might think. For example, (?!a){3} does not assert that  the
-     next  three characters are not "a". It just asserts that the
-     next character is not "a" three times.
-
-     3. Capturing subpatterns that occur inside  negative  looka-
-     head  assertions  are  counted,  but  their  entries  in the
-     offsets vector are never set. Perl sets its numerical  vari-
-     ables  from  any  such  patterns that are matched before the
-     assertion fails to match something (thereby succeeding), but
-     only  if  the negative lookahead assertion contains just one
-     branch.
-
-     4. Though binary zero characters are supported in  the  sub-
-     ject  string,  they  are  not  allowed  in  a pattern string
-     because it is passed as a normal  C  string,  terminated  by
-     zero. The escape sequence "\0" can be used in the pattern to
-     represent a binary zero.
-
-     5. The following Perl escape sequences  are  not  supported:
-     \l,  \u,  \L,  \U,  \E, \Q. In fact these are implemented by
-     Perl's general string-handling and are not part of its  pat-
-     tern matching engine.
-
-     6. The Perl \G assertion is  not  supported  as  it  is  not
-     relevant to single pattern matches.
-
-     7. Fairly obviously, PCRE does not support the (?{code}) and
-     (?p{code})  constructions. However, there is some experimen-
-     tal support for recursive patterns using the  non-Perl  item
-     (?R).
-
-     8. There are at the time of writing some  oddities  in  Perl
-     5.005_02  concerned  with  the  settings of captured strings
-     when part of a pattern is repeated.  For  example,  matching
-     "aba"  against the pattern /^(a(b)?)+$/ sets $2 to the value
-     "b", but matching "aabbaa" against /^(aa(bb)?)+$/ leaves  $2
-     unset.    However,    if   the   pattern   is   changed   to
-     /^(aa(b(b))?)+$/ then $2 (and $3) are set.
-
-     In Perl 5.004 $2 is set in both cases, and that is also true
-     of PCRE. If in the future Perl changes to a consistent state
-     that is different, PCRE may change to follow.
-
-     9. Another as yet unresolved discrepancy  is  that  in  Perl
-     5.005_02  the  pattern /^(a)?(?(1)a|b)+$/ matches the string
-     "a", whereas in PCRE it does not.  However, in both Perl and
-     PCRE /^(a)?a/ matched against "a" leaves $1 unset.
-
-     10. PCRE  provides  some  extensions  to  the  Perl  regular
-     expression facilities:
-
-     (a) Although lookbehind assertions must match  fixed  length
-     strings,  each  alternative branch of a lookbehind assertion
-     can match a different length of string. Perl 5.005  requires
-     them all to have the same length.
-
-     (b) If PCRE_DOLLAR_ENDONLY is set and PCRE_MULTILINE is  not
-     set,  the  $ meta- character matches only at the very end of
-     the string.
-
-     (c) If PCRE_EXTRA is set, a backslash followed by  a  letter
-     with no special meaning is faulted.
-
-     (d) If PCRE_UNGREEDY is set, the greediness of  the  repeti-
-     tion  quantifiers  is inverted, that is, by default they are
-     not greedy, but if followed by a question mark they are.
-
-     (e) PCRE_ANCHORED can be used to force a pattern to be tried
-     only at the start of the subject.
-
-     (f) The PCRE_NOTBOL, PCRE_NOTEOL, and PCRE_NOTEMPTY  options
-     for pcre_exec() have no Perl equivalents.
-
-     (g) The (?R) construct allows for recursive pattern matching
-     (Perl  5.6 can do this using the (?p{code}) construct, which
-     PCRE cannot of course support.)
-
-
-
-REGULAR EXPRESSION DETAILS
-     The syntax and semantics of  the  regular  expressions  sup-
-     ported  by PCRE are described below. Regular expressions are
-     also described in the Perl documentation and in a number  of
-     other  books,  some  of which have copious examples. Jeffrey
-     Friedl's  "Mastering  Regular  Expressions",  published   by
-     O'Reilly (ISBN 1-56592-257), covers them in great detail.
-
-     The description here is intended as reference documentation.
-     The basic operation of PCRE is on strings of bytes. However,
-     there is the beginnings of some support for UTF-8  character
-     strings.  To  use  this  support  you must configure PCRE to
-     include it, and then call pcre_compile() with the  PCRE_UTF8
-     option.  How  this affects the pattern matching is described
-     in the final section of this document.
-
-     A regular expression is a pattern that is matched against  a
-     subject string from left to right. Most characters stand for
-     themselves in a pattern, and match the corresponding charac-
-     ters in the subject. As a trivial example, the pattern
-
-       The quick brown fox
-
-     matches a portion of a subject string that is  identical  to
-     itself.  The  power  of  regular  expressions comes from the
-     ability to include alternatives and repetitions in the  pat-
-     tern.  These  are encoded in the pattern by the use of meta-
-     characters, which do not stand for  themselves  but  instead
-     are interpreted in some special way.
-
-     There are two different sets of meta-characters: those  that
-     are  recognized anywhere in the pattern except within square
-     brackets, and those that are recognized in square  brackets.
-     Outside square brackets, the meta-characters are as follows:
-
-       \      general escape character with several uses
-       ^      assert start of  subject  (or  line,  in  multiline
-     mode)
-       $      assert end of subject (or line, in multiline mode)
-       .      match any character except newline (by default)
-       [      start character class definition
-       |      start of alternative branch
-       (      start subpattern
-       )      end subpattern
-       ?      extends the meaning of (
-              also 0 or 1 quantifier
-              also quantifier minimizer
-       *      0 or more quantifier
-       +      1 or more quantifier
-       {      start min/max quantifier
-
-     Part of a pattern that is in square  brackets  is  called  a
-     "character  class".  In  a  character  class  the only meta-
-     characters are:
-
-       \      general escape character
-       ^      negate the class, but only if the first character
-       -      indicates character range
-       ]      terminates the character class
-
-     The following sections describe  the  use  of  each  of  the
-     meta-characters.
-
-
-
-BACKSLASH
-     The backslash character has several uses. Firstly, if it  is
-     followed  by  a  non-alphameric character, it takes away any
-     special  meaning  that  character  may  have.  This  use  of
-     backslash  as  an  escape  character applies both inside and
-     outside character classes.
-
-     For example, if you want to match a "*" character, you write
-     "\*" in the pattern. This applies whether or not the follow-
-     ing character would otherwise  be  interpreted  as  a  meta-
-     character,  so it is always safe to precede a non-alphameric
-     with "\" to specify that it stands for itself.  In  particu-
-     lar, if you want to match a backslash, you write "\\".
-
-     If a pattern is compiled with the PCRE_EXTENDED option, whi-
-     tespace in the pattern (other than in a character class) and
-     characters between a "#" outside a character class  and  the
-     next  newline  character  are ignored. An escaping backslash
-     can be used to include a whitespace or "#" character as part
-     of the pattern.
-
-     A second use of backslash provides a way  of  encoding  non-
-     printing  characters  in patterns in a visible manner. There
-     is no restriction on the appearance of non-printing  charac-
-     ters,  apart from the binary zero that terminates a pattern,
-     but when a pattern is being prepared by text editing, it  is
-     usually  easier to use one of the following escape sequences
-     than the binary character it represents:
-
-       \a     alarm, that is, the BEL character (hex 07)
-       \cx    "control-x", where x is any character
-       \e     escape (hex 1B)
-       \f     formfeed (hex 0C)
-       \n     newline (hex 0A)
-       \r     carriage return (hex 0D)
-       \t     tab (hex 09)
-       \xhh   character with hex code hh
-       \ddd   character with octal code ddd, or backreference
-
-     The precise effect of "\cx" is as follows: if "x" is a lower
-     case  letter,  it  is converted to upper case. Then bit 6 of
-     the character (hex 40) is inverted.  Thus "\cz" becomes  hex
-     1A, but "\c{" becomes hex 3B, while "\c;" becomes hex 7B.
-
-     After "\x", up to two hexadecimal digits are  read  (letters
-     can be in upper or lower case).
-
-     After "\0" up to two further octal digits are read. In  both
-     cases,  if  there are fewer than two digits, just those that
-     are present are used. Thus the sequence "\0\x\07"  specifies
-     two binary zeros followed by a BEL character.  Make sure you
-     supply two digits after the initial zero  if  the  character
-     that follows is itself an octal digit.
-
-     The handling of a backslash followed by a digit other than 0
-     is  complicated.   Outside  a character class, PCRE reads it
-     and any following digits as a decimal number. If the  number
-     is  less  than  10, or if there have been at least that many
-     previous capturing left parentheses in the  expression,  the
-     entire  sequence is taken as a back reference. A description
-     of how this works is given later, following  the  discussion
-     of parenthesized subpatterns.
-
-     Inside a character  class,  or  if  the  decimal  number  is
-     greater  than  9 and there have not been that many capturing
-     subpatterns, PCRE re-reads up to three octal digits  follow-
-     ing  the  backslash,  and  generates  a single byte from the
-     least significant 8 bits of the value. Any subsequent digits
-     stand for themselves.  For example:
-
-       \040   is another way of writing a space
-       \40    is the same, provided there are fewer than 40
-                 previous capturing subpatterns
-       \7     is always a back reference
-       \11    might be a back reference, or another way of
-                 writing a tab
-       \011   is always a tab
-       \0113  is a tab followed by the character "3"
-       \113   is the character with octal code 113 (since there
-                 can be no more than 99 back references)
-       \377   is a byte consisting entirely of 1 bits
-       \81    is either a back reference, or a binary zero
-                 followed by the two characters "8" and "1"
-
-     Note that octal values of 100 or greater must not be  intro-
-     duced  by  a  leading zero, because no more than three octal
-     digits are ever read.
-
-     All the sequences that define a single  byte  value  can  be
-     used both inside and outside character classes. In addition,
-     inside a character class, the sequence "\b"  is  interpreted
-     as  the  backspace  character  (hex 08). Outside a character
-     class it has a different meaning (see below).
-
-     The third use of backslash is for specifying generic charac-
-     ter types:
-
-       \d     any decimal digit
-       \D     any character that is not a decimal digit
-       \s     any whitespace character
-       \S     any character that is not a whitespace character
-       \w     any "word" character
-       \W     any "non-word" character
-
-     Each pair of escape sequences partitions the complete set of
-     characters  into  two  disjoint  sets.  Any  given character
-     matches one, and only one, of each pair.
-
-     A "word" character is any letter or digit or the  underscore
-     character,  that  is,  any  character which can be part of a
-     Perl "word". The definition of letters and  digits  is  con-
-     trolled  by PCRE's character tables, and may vary if locale-
-     specific matching is  taking  place  (see  "Locale  support"
-     above). For example, in the "fr" (French) locale, some char-
-     acter codes greater than 128 are used for accented  letters,
-     and these are matched by \w.
-
-     These character type sequences can appear  both  inside  and
-     outside  character classes. They each match one character of
-     the appropriate type. If the current matching  point  is  at
-     the end of the subject string, all of them fail, since there
-     is no character to match.
-
-     The fourth use of backslash is  for  certain  simple  asser-
-     tions. An assertion specifies a condition that has to be met
-     at a particular point in  a  match,  without  consuming  any
-     characters  from  the subject string. The use of subpatterns
-     for more complicated  assertions  is  described  below.  The
-     backslashed assertions are
-
-       \b     word boundary
-       \B     not a word boundary
-       \A     start of subject (independent of multiline mode)
-       \Z     end of subject or newline at  end  (independent  of
-     multiline mode)
-       \z     end of subject (independent of multiline mode)
-
-     These assertions may not appear in  character  classes  (but
-     note that "\b" has a different meaning, namely the backspace
-     character, inside a character class).
-
-     A word boundary is a position in the  subject  string  where
-     the current character and the previous character do not both
-     match \w or \W (i.e. one matches \w and  the  other  matches
-     \W),  or the start or end of the string if the first or last
-     character matches \w, respectively.
-
-     The \A, \Z, and \z assertions differ  from  the  traditional
-     circumflex  and  dollar  (described below) in that they only
-     ever match at the very start and end of the subject  string,
-     whatever  options  are  set.  They  are  not affected by the
-     PCRE_NOTBOL or PCRE_NOTEOL options. If the startoffset argu-
-     ment  of  pcre_exec()  is  non-zero, \A can never match. The
-     difference between \Z and \z is that  \Z  matches  before  a
-     newline  that is the last character of the string as well as
-     at the end of the string, whereas \z  matches  only  at  the
-     end.
-
-
-
-CIRCUMFLEX AND DOLLAR
-     Outside a character class, in the default matching mode, the
-     circumflex  character  is an assertion which is true only if
-     the current matching point is at the start  of  the  subject
-
-     string.  If  the startoffset argument of pcre_exec() is non-
-     zero, circumflex can never match. Inside a character  class,
-     circumflex has an entirely different meaning (see below).
-
-     Circumflex need not be the first character of the pattern if
-     a  number of alternatives are involved, but it should be the
-     first thing in each alternative in which it appears  if  the
-     pattern is ever to match that branch. If all possible alter-
-     natives start with a circumflex, that is, if the pattern  is
-     constrained to match only at the start of the subject, it is
-     said to be an "anchored" pattern. (There are also other con-
-     structs that can cause a pattern to be anchored.)
-
-     A dollar character is an assertion which is true only if the
-     current  matching point is at the end of the subject string,
-     or immediately before a newline character that is  the  last
-     character in the string (by default). Dollar need not be the
-     last character of the pattern if a  number  of  alternatives
-     are  involved,  but it should be the last item in any branch
-     in which it appears.  Dollar has no  special  meaning  in  a
-     character class.
-
-     The meaning of dollar can be changed so that it matches only
-     at   the   very   end   of   the   string,  by  setting  the
-     PCRE_DOLLAR_ENDONLY option at compile or matching time. This
-     does not affect the \Z assertion.
-
-     The meanings of the circumflex  and  dollar  characters  are
-     changed  if  the  PCRE_MULTILINE option is set. When this is
-     the case,  they  match  immediately  after  and  immediately
-     before an internal "\n" character, respectively, in addition
-     to matching at the start and end of the subject string.  For
-     example,  the  pattern  /^abc$/  matches  the subject string
-     "def\nabc" in multiline  mode,  but  not  otherwise.  Conse-
-     quently,  patterns  that  are  anchored  in single line mode
-     because all branches start with "^" are not anchored in mul-
-     tiline mode, and a match for circumflex is possible when the
-     startoffset  argument  of  pcre_exec()  is   non-zero.   The
-     PCRE_DOLLAR_ENDONLY  option  is ignored if PCRE_MULTILINE is
-     set.
-
-     Note that the sequences \A, \Z, and \z can be used to  match
-     the  start  and end of the subject in both modes, and if all
-     branches of a pattern start with \A is it  always  anchored,
-     whether PCRE_MULTILINE is set or not.
-
-
-
-FULL STOP (PERIOD, DOT)
-     Outside a character class, a dot in the pattern matches  any
-     one character in the subject, including a non-printing char-
-     acter, but not (by default)  newline.   If  the  PCRE_DOTALL
-
-     option  is set, dots match newlines as well. The handling of
-     dot is entirely independent of the  handling  of  circumflex
-     and  dollar,  the  only  relationship  being  that they both
-     involve newline characters. Dot has no special meaning in  a
-     character class.
-
-
-
-SQUARE BRACKETS
-     An opening square bracket introduces a character class, ter-
-     minated  by  a  closing  square  bracket.  A  closing square
-     bracket on its own is  not  special.  If  a  closing  square
-     bracket  is  required as a member of the class, it should be
-     the first data character in the class (after an initial cir-
-     cumflex, if present) or escaped with a backslash.
-
-     A character class matches a single character in the subject;
-     the  character  must  be in the set of characters defined by
-     the class, unless the first character in the class is a cir-
-     cumflex,  in which case the subject character must not be in
-     the set defined by the class. If a  circumflex  is  actually
-     required  as  a  member  of  the class, ensure it is not the
-     first character, or escape it with a backslash.
-
-     For example, the character class [aeiou] matches  any  lower
-     case vowel, while [^aeiou] matches any character that is not
-     a lower case vowel. Note that a circumflex is  just  a  con-
-     venient  notation for specifying the characters which are in
-     the class by enumerating those that are not. It  is  not  an
-     assertion:  it  still  consumes a character from the subject
-     string, and fails if the current pointer is at  the  end  of
-     the string.
-
-     When caseless matching  is  set,  any  letters  in  a  class
-     represent  both their upper case and lower case versions, so
-     for example, a caseless [aeiou] matches "A" as well as  "a",
-     and  a caseless [^aeiou] does not match "A", whereas a case-
-     ful version would.
-
-     The newline character is never treated in any special way in
-     character  classes,  whatever the setting of the PCRE_DOTALL
-     or PCRE_MULTILINE options is. A  class  such  as  [^a]  will
-     always match a newline.
-
-     The minus (hyphen) character can be used to specify a  range
-     of  characters  in  a  character  class.  For example, [d-m]
-     matches any letter between d and m, inclusive.  If  a  minus
-     character  is required in a class, it must be escaped with a
-     backslash or appear in a position where it cannot be  inter-
-     preted as indicating a range, typically as the first or last
-     character in the class.
-
-     It is not possible to have the literal character "]" as  the
-     end  character  of  a  range.  A  pattern such as [W-]46] is
-     interpreted as a class of two characters ("W" and "-")  fol-
-     lowed by a literal string "46]", so it would match "W46]" or
-     "-46]". However, if the "]" is escaped with a  backslash  it
-     is  interpreted  as  the end of range, so [W-\]46] is inter-
-     preted as a single class containing a range followed by  two
-     separate characters. The octal or hexadecimal representation
-     of "]" can also be used to end a range.
-
-     Ranges operate in ASCII collating sequence. They can also be
-     used  for  characters  specified  numerically,  for  example
-     [\000-\037]. If a range that includes letters is  used  when
-     caseless  matching  is set, it matches the letters in either
-     case. For example, [W-c] is equivalent  to  [][\^_`wxyzabc],
-     matched  caselessly,  and  if  character tables for the "fr"
-     locale are in use, [\xc8-\xcb] matches accented E characters
-     in both cases.
-
-     The character types \d, \D, \s, \S,  \w,  and  \W  may  also
-     appear  in  a  character  class, and add the characters that
-     they match to the class. For example, [\dABCDEF] matches any
-     hexadecimal  digit.  A  circumflex  can conveniently be used
-     with the upper case character types to specify a  more  res-
-     tricted set of characters than the matching lower case type.
-     For example, the class [^\W_] matches any letter  or  digit,
-     but not underscore.
-
-     All non-alphameric characters other than \,  -,  ^  (at  the
-     start)  and  the  terminating ] are non-special in character
-     classes, but it does no harm if they are escaped.
-
-
-
-POSIX CHARACTER CLASSES
-     Perl 5.6 (not yet released at the time of writing) is  going
-     to  support  the POSIX notation for character classes, which
-     uses names enclosed by  [:  and  :]   within  the  enclosing
-     square brackets. PCRE supports this notation. For example,
-
-       [01[:alpha:]%]
-
-     matches "0", "1", any alphabetic character, or "%". The sup-
-     ported class names are
-
-       alnum    letters and digits
-       alpha    letters
-       ascii    character codes 0 - 127
-       cntrl    control characters
-       digit    decimal digits (same as \d)
-       graph    printing characters, excluding space
-       lower    lower case letters
-       print    printing characters, including space
-       punct    printing characters, excluding letters and digits
-       space    white space (same as \s)
-       upper    upper case letters
-       word     "word" characters (same as \w)
-       xdigit   hexadecimal digits
-
-     The names "ascii" and "word" are  Perl  extensions.  Another
-     Perl  extension is negation, which is indicated by a ^ char-
-     acter after the colon. For example,
-
-       [12[:^digit:]]
-
-     matches "1", "2", or any non-digit.  PCRE  (and  Perl)  also
-     recogize  the POSIX syntax [.ch.] and [=ch=] where "ch" is a
-     "collating element", but these are  not  supported,  and  an
-     error is given if they are encountered.
-
-
-
-VERTICAL BAR
-     Vertical bar characters are  used  to  separate  alternative
-     patterns. For example, the pattern
-
-       gilbert|sullivan
-
-     matches either "gilbert" or "sullivan". Any number of alter-
-     natives  may  appear,  and an empty alternative is permitted
-     (matching the empty string).   The  matching  process  tries
-     each  alternative in turn, from left to right, and the first
-     one that succeeds is used. If the alternatives are within  a
-     subpattern  (defined  below),  "succeeds" means matching the
-     rest of the main pattern as well as the alternative  in  the
-     subpattern.
-
-
-
-INTERNAL OPTION SETTING
-     The settings of PCRE_CASELESS, PCRE_MULTILINE,  PCRE_DOTALL,
-     and  PCRE_EXTENDED can be changed from within the pattern by
-     a sequence of Perl option letters enclosed between "(?"  and
-     ")". The option letters are
-
-       i  for PCRE_CASELESS
-       m  for PCRE_MULTILINE
-       s  for PCRE_DOTALL
-       x  for PCRE_EXTENDED
-
-     For example, (?im) sets caseless, multiline matching. It  is
-     also possible to unset these options by preceding the letter
-     with a hyphen, and a combined setting and unsetting such  as
-     (?im-sx),  which sets PCRE_CASELESS and PCRE_MULTILINE while
-     unsetting PCRE_DOTALL and PCRE_EXTENDED, is also  permitted.
-     If  a  letter  appears both before and after the hyphen, the
-     option is unset.
-
-     The scope of these option changes depends on  where  in  the
-     pattern  the  setting  occurs. For settings that are outside
-     any subpattern (defined below), the effect is the same as if
-     the  options were set or unset at the start of matching. The
-     following patterns all behave in exactly the same way:
-
-       (?i)abc
-       a(?i)bc
-       ab(?i)c
-       abc(?i)
-
-     which in turn is the same as compiling the pattern abc  with
-     PCRE_CASELESS  set.   In  other words, such "top level" set-
-     tings apply to the whole pattern  (unless  there  are  other
-     changes  inside subpatterns). If there is more than one set-
-     ting of the same option at top level, the rightmost  setting
-     is used.
-
-     If an option change occurs inside a subpattern,  the  effect
-     is  different.  This is a change of behaviour in Perl 5.005.
-     An option change inside a subpattern affects only that  part
-     of the subpattern that follows it, so
-
-       (a(?i)b)c
-
-     matches  abc  and  aBc  and  no  other   strings   (assuming
-     PCRE_CASELESS  is  not used).  By this means, options can be
-     made to have different settings in different  parts  of  the
-     pattern.  Any  changes  made  in one alternative do carry on
-     into subsequent branches within  the  same  subpattern.  For
-     example,
-
-       (a(?i)b|c)
-
-     matches "ab", "aB", "c", and "C", even though when  matching
-     "C" the first branch is abandoned before the option setting.
-     This is because the effects of  option  settings  happen  at
-     compile  time. There would be some very weird behaviour oth-
-     erwise.
-
-     The PCRE-specific options PCRE_UNGREEDY and  PCRE_EXTRA  can
-     be changed in the same way as the Perl-compatible options by
-     using the characters U and X  respectively.  The  (?X)  flag
-     setting  is  special in that it must always occur earlier in
-     the pattern than any of the additional features it turns on,
-     even when it is at top level. It is best put at the start.
-
-
-
-SUBPATTERNS
-     Subpatterns are delimited by parentheses  (round  brackets),
-     which can be nested.  Marking part of a pattern as a subpat-
-     tern does two things:
-
-     1. It localizes a set of alternatives. For example, the pat-
-     tern
-
-       cat(aract|erpillar|)
-
-     matches one of the words "cat",  "cataract",  or  "caterpil-
-     lar".  Without  the  parentheses, it would match "cataract",
-     "erpillar" or the empty string.
-
-     2. It sets up the subpattern as a capturing  subpattern  (as
-     defined  above).   When the whole pattern matches, that por-
-     tion of the subject string that matched  the  subpattern  is
-     passed  back  to  the  caller  via  the  ovector argument of
-     pcre_exec(). Opening parentheses are counted  from  left  to
-     right (starting from 1) to obtain the numbers of the captur-
-     ing subpatterns.
-
-     For example, if the string "the red king" is matched against
-     the pattern
-
-       the ((red|white) (king|queen))
-
-     the captured substrings are "red king", "red",  and  "king",
-     and are numbered 1, 2, and 3.
-
-     The fact that plain parentheses fulfil two functions is  not
-     always  helpful.  There are often times when a grouping sub-
-     pattern is required without a capturing requirement.  If  an
-     opening parenthesis is followed by "?:", the subpattern does
-     not do any capturing, and is not counted when computing  the
-     number of any subsequent capturing subpatterns. For example,
-     if the string "the white queen" is matched against the  pat-
-     tern
-
-       the ((?:red|white) (king|queen))
-
-     the captured substrings are "white queen" and  "queen",  and
-     are  numbered  1  and 2. The maximum number of captured sub-
-     strings is 99, and the maximum number  of  all  subpatterns,
-     both capturing and non-capturing, is 200.
-
-     As a  convenient  shorthand,  if  any  option  settings  are
-     required  at  the  start  of a non-capturing subpattern, the
-     option letters may appear between the "?" and the ":".  Thus
-     the two patterns
-
-       (?i:saturday|sunday)
-       (?:(?i)saturday|sunday)
-
-     match exactly the same set of strings.  Because  alternative
-     branches  are  tried from left to right, and options are not
-     reset until the end of the subpattern is reached, an  option
-     setting  in  one  branch does affect subsequent branches, so
-     the above patterns match "SUNDAY" as well as "Saturday".
-
-
-
-REPETITION
-     Repetition is specified by quantifiers, which can follow any
-     of the following items:
-
-       a single character, possibly escaped
-       the . metacharacter
-       a character class
-       a back reference (see next section)
-       a parenthesized subpattern (unless it is  an  assertion  -
-     see below)
-
-     The general repetition quantifier specifies  a  minimum  and
-     maximum  number  of  permitted  matches,  by  giving the two
-     numbers in curly brackets (braces), separated  by  a  comma.
-     The  numbers  must be less than 65536, and the first must be
-     less than or equal to the second. For example:
-
-       z{2,4}
-
-     matches "zz", "zzz", or "zzzz". A closing brace on  its  own
-     is not a special character. If the second number is omitted,
-     but the comma is present, there is no upper  limit;  if  the
-     second number and the comma are both omitted, the quantifier
-     specifies an exact number of required matches. Thus
-
-       [aeiou]{3,}
-
-     matches at least 3 successive vowels,  but  may  match  many
-     more, while
-
-       \d{8}
-
-     matches exactly 8 digits.  An  opening  curly  bracket  that
-     appears  in a position where a quantifier is not allowed, or
-     one that does not match the syntax of a quantifier, is taken
-     as  a literal character. For example, {,6} is not a quantif-
-     ier, but a literal string of four characters.
-
-     The quantifier {0} is permitted, causing the  expression  to
-     behave  as  if the previous item and the quantifier were not
-     present.
-
-     For convenience (and  historical  compatibility)  the  three
-     most common quantifiers have single-character abbreviations:
-
-       *    is equivalent to {0,}
-       +    is equivalent to {1,}
-       ?    is equivalent to {0,1}
-
-     It is possible to construct infinite loops  by  following  a
-     subpattern  that  can  match no characters with a quantifier
-     that has no upper limit, for example:
-
-       (a?)*
-
-     Earlier versions of Perl and PCRE used to give an  error  at
-     compile  time  for such patterns. However, because there are
-     cases where this  can  be  useful,  such  patterns  are  now
-     accepted,  but  if  any repetition of the subpattern does in
-     fact match no characters, the loop is forcibly broken.
-
-     By default, the quantifiers  are  "greedy",  that  is,  they
-     match  as much as possible (up to the maximum number of per-
-     mitted times), without causing the rest of  the  pattern  to
-     fail. The classic example of where this gives problems is in
-     trying to match comments in C programs. These appear between
-     the  sequences /* and */ and within the sequence, individual
-     * and / characters may appear. An attempt to  match  C  com-
-     ments by applying the pattern
-
-       /\*.*\*/
-
-     to the string
-
-       /* first command */  not comment  /* second comment */
-
-     fails, because it matches the entire  string  owing  to  the
-     greediness of the .*  item.
-
-     However, if a quantifier is followed by a question mark,  it
-     ceases  to be greedy, and instead matches the minimum number
-     of times possible, so the pattern
-
-       /\*.*?\*/
-
-     does the right thing with the C comments. The meaning of the
-     various  quantifiers is not otherwise changed, just the pre-
-     ferred number of matches.  Do not confuse this use of  ques-
-     tion  mark  with  its  use as a quantifier in its own right.
-     Because it has two uses, it can sometimes appear doubled, as
-     in
-
-       \d??\d
-
-     which matches one digit by preference, but can match two  if
-     that is the only way the rest of the pattern matches.
-
-     If the PCRE_UNGREEDY option is set (an option which  is  not
-     available  in  Perl),  the  quantifiers  are  not  greedy by
-     default, but individual ones can be made greedy by following
-     them  with  a  question mark. In other words, it inverts the
-     default behaviour.
-
-     When a parenthesized subpattern is quantified with a minimum
-     repeat  count  that is greater than 1 or with a limited max-
-     imum, more store is required for the  compiled  pattern,  in
-     proportion to the size of the minimum or maximum.
-
-     If a pattern starts with .* or  .{0,}  and  the  PCRE_DOTALL
-     option (equivalent to Perl's /s) is set, thus allowing the .
-     to match  newlines,  the  pattern  is  implicitly  anchored,
-     because whatever follows will be tried against every charac-
-     ter position in the subject string, so there is no point  in
-     retrying  the overall match at any position after the first.
-     PCRE treats such a pattern as though it were preceded by \A.
-     In  cases where it is known that the subject string contains
-     no newlines, it is worth setting PCRE_DOTALL when  the  pat-
-     tern begins with .* in order to obtain this optimization, or
-     alternatively using ^ to indicate anchoring explicitly.
-
-     When a capturing subpattern is repeated, the value  captured
-     is the substring that matched the final iteration. For exam-
-     ple, after
-
-       (tweedle[dume]{3}\s*)+
-
-     has matched "tweedledum tweedledee" the value  of  the  cap-
-     tured  substring  is  "tweedledee".  However,  if  there are
-     nested capturing  subpatterns,  the  corresponding  captured
-     values  may  have been set in previous iterations. For exam-
-     ple, after
-
-       /(a|(b))+/
-
-     matches "aba" the value of the second captured substring  is
-     "b".
-
-
-
-BACK REFERENCES
-     Outside a character class, a backslash followed by  a  digit
-     greater  than  0  (and  possibly  further  digits) is a back
-     reference to a capturing subpattern  earlier  (i.e.  to  its
-     left)  in  the  pattern,  provided there have been that many
-     previous capturing left parentheses.
-
-     However, if the decimal number following  the  backslash  is
-     less  than  10,  it is always taken as a back reference, and
-     causes an error only if there are not  that  many  capturing
-     left  parentheses in the entire pattern. In other words, the
-     parentheses that are referenced need not be to the  left  of
-     the  reference  for  numbers  less  than 10. See the section
-     entitled "Backslash" above for further details of  the  han-
-     dling of digits following a backslash.
-
-     A back reference matches whatever actually matched the  cap-
-     turing subpattern in the current subject string, rather than
-     anything matching the subpattern itself. So the pattern
-
-       (sens|respons)e and \1ibility
-
-     matches "sense and sensibility" and "response and  responsi-
-     bility",  but  not  "sense  and  responsibility". If caseful
-     matching is in force at the time of the back reference,  the
-     case of letters is relevant. For example,
-
-       ((?i)rah)\s+\1
-
-     matches "rah rah" and "RAH RAH", but  not  "RAH  rah",  even
-     though  the  original  capturing subpattern is matched case-
-     lessly.
-
-     There may be more than one back reference to the  same  sub-
-     pattern.  If  a  subpattern  has not actually been used in a
-     particular match, any back references to it always fail. For
-     example, the pattern
-
-       (a|(bc))\2
-
-     always fails if it starts to match  "a"  rather  than  "bc".
-     Because  there  may  be up to 99 back references, all digits
-     following the backslash are taken as  part  of  a  potential
-     back reference number. If the pattern continues with a digit
-     character, some delimiter must be used to terminate the back
-     reference.   If the PCRE_EXTENDED option is set, this can be
-     whitespace. Otherwise an empty comment can be used.
-
-     A back reference that occurs inside the parentheses to which
-     it  refers  fails when the subpattern is first used, so, for
-     example, (a\1) never matches.  However, such references  can
-     be useful inside repeated subpatterns. For example, the pat-
-     tern
-
-       (a|b\1)+
-
-     matches any number of "a"s and also "aba", "ababbaa" etc. At
-     each iteration of the subpattern, the back reference matches
-     the  character  string   corresponding   to   the   previous
-     iteration.  In  order  for this to work, the pattern must be
-     such that the first iteration does not  need  to  match  the
-     back  reference.  This  can be done using alternation, as in
-     the example above, or by a  quantifier  with  a  minimum  of
-     zero.
-
-
-
-ASSERTIONS
-     An assertion is  a  test  on  the  characters  following  or
-     preceding  the current matching point that does not actually
-     consume any characters. The simple assertions coded  as  \b,
-     \B,  \A,  \Z,  \z, ^ and $ are described above. More compli-
-     cated assertions are coded as  subpatterns.  There  are  two
-     kinds:  those that look ahead of the current position in the
-     subject string, and those that look behind it.
-
-     An assertion subpattern is matched in the normal way, except
-     that  it  does not cause the current matching position to be
-     changed. Lookahead assertions start with  (?=  for  positive
-     assertions and (?! for negative assertions. For example,
-
-       \w+(?=;)
-
-     matches a word followed by a semicolon, but does not include
-     the semicolon in the match, and
-
-       foo(?!bar)
-
-     matches any occurrence of "foo"  that  is  not  followed  by
-     "bar". Note that the apparently similar pattern
-
-       (?!foo)bar
-
-     does not find an occurrence of "bar"  that  is  preceded  by
-     something other than "foo"; it finds any occurrence of "bar"
-     whatsoever, because the assertion  (?!foo)  is  always  true
-     when  the  next  three  characters  are  "bar". A lookbehind
-     assertion is needed to achieve this effect.
-
-     Lookbehind assertions start with (?<=  for  positive  asser-
-     tions and (?<! for negative assertions. For example,
-
-       (?<!foo)bar
-
-     does find an occurrence of "bar" that  is  not  preceded  by
-     "foo". The contents of a lookbehind assertion are restricted
-     such that all the strings  it  matches  must  have  a  fixed
-     length.  However, if there are several alternatives, they do
-     not all have to have the same fixed length. Thus
-
-       (?<=bullock|donkey)
-
-     is permitted, but
-
-       (?<!dogs?|cats?)
-
-     causes an error at compile time. Branches  that  match  dif-
-     ferent length strings are permitted only at the top level of
-     a lookbehind assertion. This is an extension  compared  with
-     Perl  5.005,  which  requires all branches to match the same
-     length of string. An assertion such as
-
-       (?<=ab(c|de))
-
-     is not permitted, because its single  top-level  branch  can
-     match two different lengths, but it is acceptable if rewrit-
-     ten to use two top-level branches:
-
-       (?<=abc|abde)
-
-     The implementation of lookbehind  assertions  is,  for  each
-     alternative,  to  temporarily move the current position back
-     by the fixed width and then  try  to  match.  If  there  are
-     insufficient  characters  before  the  current position, the
-     match is deemed to fail.  Lookbehinds  in  conjunction  with
-     once-only  subpatterns can be particularly useful for match-
-     ing at the ends of strings; an example is given at  the  end
-     of the section on once-only subpatterns.
-
-     Several assertions (of any sort) may  occur  in  succession.
-     For example,
-
-       (?<=\d{3})(?<!999)foo
-
-     matches "foo" preceded by three digits that are  not  "999".
-     Notice  that each of the assertions is applied independently
-     at the same point in the subject string. First  there  is  a
-     check that the previous three characters are all digits, and
-     then there is a check that the same three characters are not
-     "999".   This  pattern  does not match "foo" preceded by six
-     characters, the first of which are digits and the last three
-     of  which  are  not  "999".  For  example,  it doesn't match
-     "123abcfoo". A pattern to do that is
-
-       (?<=\d{3}...)(?<!999)foo
-
-     This time the first assertion looks  at  the  preceding  six
-     characters,  checking  that  the first three are digits, and
-     then the second assertion checks that  the  preceding  three
-     characters are not "999".
-
-     Assertions can be nested in any combination. For example,
-
-       (?<=(?<!foo)bar)baz
-
-     matches an occurrence of "baz" that  is  preceded  by  "bar"
-     which in turn is not preceded by "foo", while
-
-       (?<=\d{3}(?!999)...)foo
-
-     is another pattern which matches  "foo"  preceded  by  three
-     digits and any three characters that are not "999".
-
-     Assertion subpatterns are not capturing subpatterns, and may
-     not  be  repeated,  because  it makes no sense to assert the
-     same thing several times. If any kind of assertion  contains
-     capturing  subpatterns  within it, these are counted for the
-     purposes of numbering the capturing subpatterns in the whole
-     pattern.   However,  substring capturing is carried out only
-     for positive assertions, because it does not make sense  for
-     negative assertions.
-
-     Assertions count towards the maximum  of  200  parenthesized
-     subpatterns.
-
-
-
-ONCE-ONLY SUBPATTERNS
-     With both maximizing and minimizing repetition,  failure  of
-     what  follows  normally  causes  the repeated item to be re-
-     evaluated to see if a different number of repeats allows the
-     rest  of  the  pattern  to  match. Sometimes it is useful to
-     prevent this, either to change the nature of the  match,  or
-     to  cause  it fail earlier than it otherwise might, when the
-     author of the pattern knows there is no  point  in  carrying
-     on.
-
-     Consider, for example, the pattern \d+foo  when  applied  to
-     the subject line
-
-       123456bar
-
-     After matching all 6 digits and then failing to match "foo",
-     the normal action of the matcher is to try again with only 5
-     digits matching the \d+ item, and then with 4,  and  so  on,
-     before ultimately failing. Once-only subpatterns provide the
-     means for specifying that once a portion of the pattern  has
-     matched,  it  is  not to be re-evaluated in this way, so the
-     matcher would give up immediately on failing to match  "foo"
-     the  first  time.  The  notation  is another kind of special
-     parenthesis, starting with (?> as in this example:
-
-       (?>\d+)bar
-
-     This kind of parenthesis "locks up" the  part of the pattern
-     it  contains once it has matched, and a failure further into
-     the  pattern  is  prevented  from  backtracking   into   it.
-     Backtracking  past  it  to previous items, however, works as
-     normal.
-
-     An alternative description is that a subpattern of this type
-     matches  the  string  of  characters that an identical stan-
-     dalone pattern would match, if anchored at the current point
-     in the subject string.
-
-     Once-only subpatterns are not capturing subpatterns.  Simple
-     cases  such as the above example can be thought of as a max-
-     imizing repeat that must  swallow  everything  it  can.  So,
-     while both \d+ and \d+? are prepared to adjust the number of
-     digits they match in order to make the rest of  the  pattern
-     match, (?>\d+) can only match an entire sequence of digits.
-
-     This construction can of course contain arbitrarily  compli-
-     cated subpatterns, and it can be nested.
-
-     Once-only subpatterns can be used in conjunction with  look-
-     behind  assertions  to specify efficient matching at the end
-     of the subject string. Consider a simple pattern such as
-
-       abcd$
-
-     when applied to a long string which does not match.  Because
-     matching  proceeds  from  left  to right, PCRE will look for
-     each "a" in the subject and then see if what follows matches
-     the rest of the pattern. If the pattern is specified as
-
-       ^.*abcd$
-
-     the initial .* matches the entire string at first, but  when
-     this  fails  (because  there  is no following "a"), it back-
-     tracks to match all but the last character, then all but the
-     last  two  characters,  and so on. Once again the search for
-     "a" covers the entire string, from right to left, so we  are
-     no better off. However, if the pattern is written as
-
-       ^(?>.*)(?<=abcd)
-
-     there can be no backtracking for the .* item; it  can  match
-     only  the entire string. The subsequent lookbehind assertion
-     does a single test on the last four characters. If it fails,
-     the match fails immediately. For long strings, this approach
-     makes a significant difference to the processing time.
-
-     When a pattern contains an unlimited repeat inside a subpat-
-     tern  that  can  itself  be  repeated an unlimited number of
-     times, the use of a once-only subpattern is the only way  to
-     avoid  some  failing matches taking a very long time indeed.
-     The pattern
-
-       (\D+|<\d+>)*[!?]
-
-     matches an unlimited number of substrings that  either  con-
-     sist  of  non-digits,  or digits enclosed in <>, followed by
-     either ! or ?. When it matches, it runs quickly. However, if
-     it is applied to
-
-       aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
-
-     it takes a long  time  before  reporting  failure.  This  is
-     because the string can be divided between the two repeats in
-     a large number of ways, and all have to be tried. (The exam-
-     ple  used  [!?]  rather  than a single character at the end,
-     because both PCRE and Perl have an optimization that  allows
-     for  fast  failure  when  a  single  character is used. They
-     remember the last single character that is  required  for  a
-     match,  and  fail early if it is not present in the string.)
-     If the pattern is changed to
-
-       ((?>\D+)|<\d+>)*[!?]
-
-     sequences of non-digits cannot be broken, and  failure  hap-
-     pens quickly.
-
-
-
-CONDITIONAL SUBPATTERNS
-     It is possible to cause the matching process to obey a  sub-
-     pattern  conditionally  or to choose between two alternative
-     subpatterns, depending on the result  of  an  assertion,  or
-     whether  a previous capturing subpattern matched or not. The
-     two possible forms of conditional subpattern are
-
-       (?(condition)yes-pattern)
-       (?(condition)yes-pattern|no-pattern)
-
-     If the condition is satisfied, the yes-pattern is used; oth-
-     erwise  the  no-pattern  (if  present) is used. If there are
-     more than two alternatives in the subpattern, a compile-time
-     error occurs.
-
-     There are two kinds of condition. If the  text  between  the
-     parentheses  consists of a sequence of digits, the condition
-     is satisfied if the capturing subpattern of that number  has
-     previously  matched.  The  number must be greater than zero.
-     Consider  the  following  pattern,   which   contains   non-
-     significant white space to make it more readable (assume the
-     PCRE_EXTENDED option) and to divide it into three parts  for
-     ease of discussion:
-
-       ( \( )?    [^()]+    (?(1) \) )
-
-     The first part matches an optional opening parenthesis,  and
-     if  that character is present, sets it as the first captured
-     substring. The second part matches one  or  more  characters
-     that  are  not  parentheses. The third part is a conditional
-     subpattern that tests whether the first set  of  parentheses
-     matched  or  not.  If  they did, that is, if subject started
-     with an opening parenthesis, the condition is true,  and  so
-     the  yes-pattern  is  executed  and a closing parenthesis is
-     required. Otherwise, since no-pattern is  not  present,  the
-     subpattern  matches  nothing.  In  other words, this pattern
-     matches a sequence of non-parentheses,  optionally  enclosed
-     in parentheses.
-
-     If the condition is not a sequence of digits, it must be  an
-     assertion.  This  may be a positive or negative lookahead or
-     lookbehind assertion. Consider this pattern, again  contain-
-     ing  non-significant  white space, and with the two alterna-
-     tives on the second line:
-
-       (?(?=[^a-z]*[a-z])
-       \d{2}-[a-z]{3}-\d{2}  |  \d{2}-\d{2}-\d{2} )
-
-     The condition is a positive lookahead assertion that matches
-     an optional sequence of non-letters followed by a letter. In
-     other words, it tests for  the  presence  of  at  least  one
-     letter  in the subject. If a letter is found, the subject is
-     matched against  the  first  alternative;  otherwise  it  is
-     matched  against the second. This pattern matches strings in
-     one of the two forms dd-aaa-dd or dd-dd-dd,  where  aaa  are
-     letters and dd are digits.
-
-
-
-COMMENTS
-     The sequence (?# marks the start of a comment which  contin-
-     ues  up  to the next closing parenthesis. Nested parentheses
-     are not permitted. The characters that  make  up  a  comment
-     play no part in the pattern matching at all.
-
-     If the PCRE_EXTENDED option is set, an unescaped # character
-     outside  a character class introduces a comment that contin-
-     ues up to the next newline character in the pattern.
-
-
-
-RECURSIVE PATTERNS
-     Consider the problem of matching a  string  in  parentheses,
-     allowing  for  unlimited nested parentheses. Without the use
-     of recursion, the best that can be done is to use a  pattern
-     that  matches  up  to some fixed depth of nesting. It is not
-     possible to handle an arbitrary nesting depth. Perl 5.6  has
-     provided   an  experimental  facility  that  allows  regular
-     expressions to recurse (amongst other things). It does  this
-     by  interpolating  Perl  code in the expression at run time,
-     and the code can refer to the expression itself. A Perl pat-
-     tern  to  solve  the parentheses problem can be created like
-     this:
-
-       $re = qr{\( (?: (?>[^()]+) | (?p{$re}) )* \)}x;
-
-     The (?p{...}) item interpolates Perl code at run  time,  and
-     in  this  case refers recursively to the pattern in which it
-     appears. Obviously, PCRE cannot support the interpolation of
-     Perl  code.  Instead,  the special item (?R) is provided for
-     the specific case of recursion. This PCRE pattern solves the
-     parentheses  problem (assume the PCRE_EXTENDED option is set
-     so that white space is ignored):
-
-       \( ( (?>[^()]+) | (?R) )* \)
-
-     First it matches an opening parenthesis. Then it matches any
-     number  of substrings which can either be a sequence of non-
-     parentheses, or a recursive  match  of  the  pattern  itself
-     (i.e. a correctly parenthesized substring). Finally there is
-     a closing parenthesis.
-
-     This particular example pattern  contains  nested  unlimited
-     repeats, and so the use of a once-only subpattern for match-
-     ing strings of non-parentheses is  important  when  applying
-     the  pattern to strings that do not match. For example, when
-     it is applied to
-
-       (aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa()
-
-     it yields "no match" quickly. However, if a  once-only  sub-
-     pattern  is  not  used,  the match runs for a very long time
-     indeed because there are so many different ways the + and  *
-     repeats  can carve up the subject, and all have to be tested
-     before failure can be reported.
-
-     The values set for any capturing subpatterns are those  from
-     the outermost level of the recursion at which the subpattern
-     value is set. If the pattern above is matched against
-
-       (ab(cd)ef)
-
-     the value for the capturing parentheses is  "ef",  which  is
-     the  last  value  taken  on  at the top level. If additional
-     parentheses are added, giving
-
-       \( ( ( (?>[^()]+) | (?R) )* ) \)
-          ^                        ^
-          ^                        ^ the string they  capture  is
-     "ab(cd)ef",  the  contents  of the top level parentheses. If
-     there are more than 15 capturing parentheses in  a  pattern,
-     PCRE  has  to  obtain  extra  memory  to store data during a
-     recursion, which it does by using  pcre_malloc,  freeing  it
-     via  pcre_free  afterwards. If no memory can be obtained, it
-     saves data for the first 15 capturing parentheses  only,  as
-     there is no way to give an out-of-memory error from within a
-     recursion.
-
-
-
-PERFORMANCE
-     Certain items that may appear in patterns are more efficient
-     than  others.  It is more efficient to use a character class
-     like [aeiou] than a set of alternatives such as (a|e|i|o|u).
-     In  general,  the  simplest  construction  that provides the
-     required behaviour is usually the  most  efficient.  Jeffrey
-     Friedl's  book contains a lot of discussion about optimizing
-     regular expressions for efficient performance.
-
-     When a pattern begins with .* and the PCRE_DOTALL option  is
-     set,  the  pattern  is implicitly anchored by PCRE, since it
-     can match only at the start of a subject string. However, if
-     PCRE_DOTALL  is not set, PCRE cannot make this optimization,
-     because the . metacharacter does not then match  a  newline,
-     and if the subject string contains newlines, the pattern may
-     match from the character immediately following one  of  them
-     instead of from the very start. For example, the pattern
-
-       (.*) second
-
-     matches the subject "first\nand second" (where \n stands for
-     a newline character) with the first captured substring being
-     "and". In order to do this, PCRE  has  to  retry  the  match
-     starting after every newline in the subject.
-
-     If you are using such a pattern with subject strings that do
-     not  contain  newlines,  the best performance is obtained by
-     setting PCRE_DOTALL, or starting the  pattern  with  ^.*  to
-     indicate  explicit anchoring. That saves PCRE from having to
-     scan along the subject looking for a newline to restart at.
-
-     Beware of patterns that contain nested  indefinite  repeats.
-     These  can  take a long time to run when applied to a string
-     that does not match. Consider the pattern fragment
-
-       (a+)*
-
-     This can match "aaaa" in 33 different ways, and this  number
-     increases  very  rapidly  as  the string gets longer. (The *
-     repeat can match 0, 1, 2, 3, or 4 times,  and  for  each  of
-     those  cases other than 0, the + repeats can match different
-     numbers of times.) When the remainder of the pattern is such
-     that  the entire match is going to fail, PCRE has in princi-
-     ple to try every possible variation, and this  can  take  an
-     extremely long time.
-
-     An optimization catches some of the more simple  cases  such
-     as
-
-       (a+)*b
-
-     where a literal character follows. Before embarking  on  the
-     standard matching procedure, PCRE checks that there is a "b"
-     later in the subject string, and if there is not,  it  fails
-     the  match  immediately. However, when there is no following
-     literal this optimization cannot be used. You  can  see  the
-     difference by comparing the behaviour of
-
-       (a+)*\d
-
-     with the pattern above. The former gives  a  failure  almost
-     instantly  when  applied  to a whole line of "a" characters,
-     whereas the latter takes an appreciable  time  with  strings
-     longer than about 20 characters.
-
-
-
-UTF-8 SUPPORT
-     Starting at release 3.3, PCRE has some support for character
-     strings encoded in the UTF-8 format. This is incomplete, and
-     is regarded as experimental. In order to use  it,  you  must
-     configure PCRE to include UTF-8 support in the code, and, in
-     addition, you must call pcre_compile()  with  the  PCRE_UTF8
-     option flag. When you do this, both the pattern and any sub-
-     ject strings that are matched  against  it  are  treated  as
-     UTF-8  strings instead of just strings of bytes, but only in
-     the cases that are mentioned below.
-
-     If you compile PCRE with UTF-8 support, but do not use it at
-     run  time,  the  library will be a bit bigger, but the addi-
-     tional run time overhead is limited to testing the PCRE_UTF8
-     flag in several places, so should not be very large.
-
-     PCRE assumes that the strings  it  is  given  contain  valid
-     UTF-8  codes. It does not diagnose invalid UTF-8 strings. If
-     you pass invalid UTF-8 strings  to  PCRE,  the  results  are
-     undefined.
-
-     Running with PCRE_UTF8 set causes these changes in  the  way
-     PCRE works:
-
-     1. In a pattern, the escape sequence \x{...}, where the con-
-     tents  of  the  braces is a string of hexadecimal digits, is
-     interpreted as a UTF-8 character whose code  number  is  the
-     given   hexadecimal  number,  for  example:  \x{1234}.  This
-     inserts from one to six  literal  bytes  into  the  pattern,
-     using the UTF-8 encoding. If a non-hexadecimal digit appears
-     between the braces, the item is not recognized.
-
-     2. The original hexadecimal escape sequence, \xhh, generates
-     a two-byte UTF-8 character if its value is greater than 127.
-
-     3. Repeat quantifiers are NOT correctly handled if they fol-
-     low  a  multibyte character. For example, \x{100}* and \xc3+
-     do not work. If you want to repeat such characters, you must
-     enclose  them  in  non-capturing  parentheses,  for  example
-     (?:\x{100}), at present.
-
-     4. The dot metacharacter matches one UTF-8 character instead
-     of a single byte.
-
-     5. Unlike literal UTF-8 characters,  the  dot  metacharacter
-     followed  by  a  repeat quantifier does operate correctly on
-     UTF-8 characters instead of single bytes.
-
-     4. Although the \x{...} escape is permitted in  a  character
-     class,  characters  whose values are greater than 255 cannot
-     be included in a class.
-
-     5. A class is matched against a UTF-8 character  instead  of
-     just  a  single byte, but it can match only characters whose
-     values are less than 256.  Characters  with  greater  values
-     always fail to match a class.
-
-     6. Repeated classes work correctly on multiple characters.
-
-     7. Classes containing just a single character whose value is
-     greater than 127 (but less than 256), for example, [\x80] or
-     [^\x{93}], do not work because these are optimized into sin-
-     gle  byte  matches.  In the first case, of course, the class
-     brackets are just redundant.
-
-     8. Lookbehind assertions move backwards in the subject by  a
-     fixed  number  of  characters  instead  of a fixed number of
-     bytes. Simple cases have been tested to work correctly,  but
-     there may be hidden gotchas herein.
-
-     9. The character types  such  as  \d  and  \w  do  not  work
-     correctly  with  UTF-8  characters.  They continue to test a
-     single byte.
-
-     10. Anything not explicitly mentioned here continues to work
-     in bytes rather than in characters.
-
-     The following UTF-8 features of  Perl  5.6  are  not  imple-
-     mented:
-     1. The escape sequence \C to match a single byte.
-
-     2. The use of Unicode tables and properties and escapes  \p,
-     \P, and \X.
-
-
-
-AUTHOR
-     Philip Hazel <ph10@cam.ac.uk>
-     University Computing Service,
-     New Museums Site,
-     Cambridge CB2 3QG, England.
-     Phone: +44 1223 334714
-
-     Last updated: 28 August 2000,
-       the 250th anniversary of the death of J.S. Bach.
-     Copyright (c) 1997-2000 University of Cambridge.
diff --git a/ext/pcre/pcrelib/doc/pcregrep.1 b/ext/pcre/pcrelib/doc/pcregrep.1
deleted file mode 100644
index 41b9051037..0000000000
--- a/ext/pcre/pcrelib/doc/pcregrep.1
+++ /dev/null
@@ -1,76 +0,0 @@
-.TH PCREGREP 1
-.SH NAME
-pcregrep - a grep with Perl-compatible regular expressions.
-.SH SYNOPSIS
-.B pcregrep [-Vchilnsvx] pattern [file] ...
-
-
-.SH DESCRIPTION
-\fBpcregrep\fR searches files for character patterns, in the same way as other
-grep commands do, but it uses the PCRE regular expression library to support
-patterns that are compatible with the regular expressions of Perl 5. See
-\fBpcre(3)\fR for a full description of syntax and semantics.
-
-If no files are specified, \fBpcregrep\fR reads the standard input. By default,
-each line that matches the pattern is copied to the standard output, and if
-there is more than one file, the file name is printed before each line of
-output. However, there are options that can change how \fBpcregrep\fR behaves.
-
-Lines are limited to BUFSIZ characters. BUFSIZ is defined in \fB<stdio.h>\fR.
-The newline character is removed from the end of each line before it is matched
-against the pattern.
-
-
-.SH OPTIONS
-.TP 10
-\fB-V\fR
-Write the version number of the PCRE library being used to the standard error
-stream.
-.TP
-\fB-c\fR
-Do not print individual lines; instead just print a count of the number of
-lines that would otherwise have been printed. If several files are given, a
-count is printed for each of them.
-.TP
-\fB-h\fR
-Suppress printing of filenames when searching multiple files.
-.TP
-\fB-i\fR
-Ignore upper/lower case distinctions during comparisons.
-.TP
-\fB-l\fR
-Instead of printing lines from the files, just print the names of the files
-containing lines that would have been printed. Each file name is printed
-once, on a separate line.
-.TP
-\fB-n\fR
-Precede each line by its line number in the file.
-.TP
-\fB-s\fR
-Work silently, that is, display nothing except error messages.
-The exit status indicates whether any matches were found.
-.TP
-\fB-v\fR
-Invert the sense of the match, so that lines which do \fInot\fR match the
-pattern are now the ones that are found.
-.TP
-\fB-x\fR
-Force the pattern to be anchored (it must start matching at the beginning of
-the line) and in addition, require it to match the entire line. This is
-equivalent to having ^ and $ characters at the start and end of each
-alternative branch in the regular expression.
-
-
-.SH SEE ALSO
-\fBpcre(3)\fR, Perl 5 documentation
-
-
-.SH DIAGNOSTICS
-Exit status is 0 if any matches were found, 1 if no matches were found, and 2
-for syntax errors or inacessible files (even if matches were found).
-
-
-.SH AUTHOR
-Philip Hazel <ph10@cam.ac.uk>
-.br
-Copyright (c) 1997-2000 University of Cambridge.
diff --git a/ext/pcre/pcrelib/doc/pcregrep.html b/ext/pcre/pcrelib/doc/pcregrep.html
deleted file mode 100644
index 77da7c426c..0000000000
--- a/ext/pcre/pcrelib/doc/pcregrep.html
+++ /dev/null
@@ -1,105 +0,0 @@
-<HTML>
-<HEAD>
-<TITLE>pcregrep specification</TITLE>
-</HEAD>
-<body bgcolor="#FFFFFF" text="#00005A">
-<H1>pcregrep specification</H1>
-This HTML document has been generated automatically from the original man page.
-If there is any nonsense in it, please consult the man page in case the
-conversion went wrong.
-<UL>
-<LI><A NAME="TOC1" HREF="#SEC1">NAME</A>
-<LI><A NAME="TOC2" HREF="#SEC2">SYNOPSIS</A>
-<LI><A NAME="TOC3" HREF="#SEC3">DESCRIPTION</A>
-<LI><A NAME="TOC4" HREF="#SEC4">OPTIONS</A>
-<LI><A NAME="TOC5" HREF="#SEC5">SEE ALSO</A>
-<LI><A NAME="TOC6" HREF="#SEC6">DIAGNOSTICS</A>
-<LI><A NAME="TOC7" HREF="#SEC7">AUTHOR</A>
-</UL>
-<LI><A NAME="SEC1" HREF="#TOC1">NAME</A>
-<P>
-pcregrep - a grep with Perl-compatible regular expressions.
-</P>
-<LI><A NAME="SEC2" HREF="#TOC1">SYNOPSIS</A>
-<P>
-<B>pcregrep [-Vchilnsvx] pattern [file] ...</B>
-</P>
-<LI><A NAME="SEC3" HREF="#TOC1">DESCRIPTION</A>
-<P>
-<B>pcregrep</B> searches files for character patterns, in the same way as other
-grep commands do, but it uses the PCRE regular expression library to support
-patterns that are compatible with the regular expressions of Perl 5. See
-<B>pcre(3)</B> for a full description of syntax and semantics.
-</P>
-<P>
-If no files are specified, <B>pcregrep</B> reads the standard input. By default,
-each line that matches the pattern is copied to the standard output, and if
-there is more than one file, the file name is printed before each line of
-output. However, there are options that can change how <B>pcregrep</B> behaves.
-</P>
-<P>
-Lines are limited to BUFSIZ characters. BUFSIZ is defined in <B>&#60;stdio.h&#62;</B>.
-The newline character is removed from the end of each line before it is matched
-against the pattern.
-</P>
-<LI><A NAME="SEC4" HREF="#TOC1">OPTIONS</A>
-<P>
-<B>-V</B>
-Write the version number of the PCRE library being used to the standard error
-stream.
-</P>
-<P>
-<B>-c</B>
-Do not print individual lines; instead just print a count of the number of
-lines that would otherwise have been printed. If several files are given, a
-count is printed for each of them.
-</P>
-<P>
-<B>-h</B>
-Suppress printing of filenames when searching multiple files.
-</P>
-<P>
-<B>-i</B>
-Ignore upper/lower case distinctions during comparisons.
-</P>
-<P>
-<B>-l</B>
-Instead of printing lines from the files, just print the names of the files
-containing lines that would have been printed. Each file name is printed
-once, on a separate line.
-</P>
-<P>
-<B>-n</B>
-Precede each line by its line number in the file.
-</P>
-<P>
-<B>-s</B>
-Work silently, that is, display nothing except error messages.
-The exit status indicates whether any matches were found.
-</P>
-<P>
-<B>-v</B>
-Invert the sense of the match, so that lines which do <I>not</I> match the
-pattern are now the ones that are found.
-</P>
-<P>
-<B>-x</B>
-Force the pattern to be anchored (it must start matching at the beginning of
-the line) and in addition, require it to match the entire line. This is
-equivalent to having ^ and $ characters at the start and end of each
-alternative branch in the regular expression.
-</P>
-<LI><A NAME="SEC5" HREF="#TOC1">SEE ALSO</A>
-<P>
-<B>pcre(3)</B>, Perl 5 documentation
-</P>
-<LI><A NAME="SEC6" HREF="#TOC1">DIAGNOSTICS</A>
-<P>
-Exit status is 0 if any matches were found, 1 if no matches were found, and 2
-for syntax errors or inacessible files (even if matches were found).
-</P>
-<LI><A NAME="SEC7" HREF="#TOC1">AUTHOR</A>
-<P>
-Philip Hazel &#60;ph10@cam.ac.uk&#62;
-<BR>
-Copyright (c) 1997-2000 University of Cambridge.
diff --git a/ext/pcre/pcrelib/doc/pcregrep.txt b/ext/pcre/pcrelib/doc/pcregrep.txt
deleted file mode 100644
index 3483f9e158..0000000000
--- a/ext/pcre/pcrelib/doc/pcregrep.txt
+++ /dev/null
@@ -1,87 +0,0 @@
-NAME
-     pcregrep - a grep with Perl-compatible regular expressions.
-
-
-
-SYNOPSIS
-     pcregrep [-Vchilnsvx] pattern [file] ...
-
-
-
-DESCRIPTION
-     pcregrep searches files for character patterns, in the  same
-     way  as other grep commands do, but it uses the PCRE regular
-     expression library to support patterns that  are  compatible
-     with  the  regular  expressions of Perl 5. See pcre(3) for a
-     full description of syntax and semantics.
-
-     If no files  are  specified,  pcregrep  reads  the  standard
-     input.  By  default,  each  line that matches the pattern is
-     copied to the standard output, and if there is more than one
-     file,  the  file name is printed before each line of output.
-     However, there are options  that  can  change  how  pcregrep
-     behaves.
-
-     Lines are limited to BUFSIZ characters. BUFSIZ is defined in
-     <stdio.h>.  The newline character is removed from the end of
-     each line before it is matched against the pattern.
-
-
-
-OPTIONS
-     -V        Write the version number of the PCRE library being
-               used to the standard error stream.
-
-     -c        Do not print individual lines; instead just  print
-               a  count  of the number of lines that would other-
-               wise have  been  printed.  If  several  files  are
-               given, a count is printed for each of them.
-
-     -h        Suppress printing of filenames when searching mul-
-               tiple files.
-
-     -i        Ignore upper/lower case distinctions  during  com-
-               parisons.
-
-     -l        Instead of printing lines  from  the  files,  just
-               print the names of the files containing lines that
-               would have been printed. Each file name is printed
-               once, on a separate line.
-
-     -n        Precede each line by its line number in the file.
-
-     -s        Work silently, that  is,  display  nothing  except
-               error messages.  The exit status indicates whether
-               any matches were found.
-
-     -v        Invert the sense of the match, so that lines which
-               do not match the pattern are now the ones that are
-               found.
-
-     -x        Force the pattern to be anchored  (it  must  start
-               matching  at  the  beginning  of  the line) and in
-               addition, require it to  match  the  entire  line.
-               This is equivalent to having ^ and $ characters at
-               the start and end of each  alternative  branch  in
-               the regular expression.
-
-
-
-SEE ALSO
-     pcre(3), Perl 5 documentation
-
-
-
-
-
-DIAGNOSTICS
-     Exit status is 0 if any matches were found, 1 if no  matches
-     were  found,  and  2  for syntax errors or inacessible files
-     (even if matches were found).
-
-
-
-AUTHOR
-     Philip Hazel <ph10@cam.ac.uk>
-     Copyright (c) 1997-2000 University of Cambridge.
-
diff --git a/ext/pcre/pcrelib/doc/pcreposix.3 b/ext/pcre/pcrelib/doc/pcreposix.3
deleted file mode 100644
index 41716ead91..0000000000
--- a/ext/pcre/pcrelib/doc/pcreposix.3
+++ /dev/null
@@ -1,149 +0,0 @@
-.TH PCRE 3
-.SH NAME
-pcreposix - POSIX API for Perl-compatible regular expressions.
-.SH SYNOPSIS
-.B #include <pcreposix.h>
-.PP
-.SM
-.br
-.B int regcomp(regex_t *\fIpreg\fR, const char *\fIpattern\fR,
-.ti +5n
-.B int \fIcflags\fR);
-.PP
-.br
-.B int regexec(regex_t *\fIpreg\fR, const char *\fIstring\fR,
-.ti +5n
-.B size_t \fInmatch\fR, regmatch_t \fIpmatch\fR[], int \fIeflags\fR);
-.PP
-.br
-.B size_t regerror(int \fIerrcode\fR, const regex_t *\fIpreg\fR,
-.ti +5n
-.B char *\fIerrbuf\fR, size_t \fIerrbuf_size\fR);
-.PP
-.br
-.B void regfree(regex_t *\fIpreg\fR);
-
-
-.SH DESCRIPTION
-This set of functions provides a POSIX-style API to the PCRE regular expression
-package. See the \fBpcre\fR documentation for a description of the native API,
-which contains additional functionality.
-
-The functions described here are just wrapper functions that ultimately call
-the native API. Their prototypes are defined in the \fBpcreposix.h\fR header
-file, and on Unix systems the library itself is called \fBpcreposix.a\fR, so
-can be accessed by adding \fB-lpcreposix\fR to the command for linking an
-application which uses them. Because the POSIX functions call the native ones,
-it is also necessary to add \fR-lpcre\fR.
-
-I have implemented only those option bits that can be reasonably mapped to PCRE
-native options. In addition, the options REG_EXTENDED and REG_NOSUB are defined
-with the value zero. They have no effect, but since programs that are written
-to the POSIX interface often use them, this makes it easier to slot in PCRE as
-a replacement library. Other POSIX options are not even defined.
-
-When PCRE is called via these functions, it is only the API that is POSIX-like
-in style. The syntax and semantics of the regular expressions themselves are
-still those of Perl, subject to the setting of various PCRE options, as
-described below.
-
-The header for these functions is supplied as \fBpcreposix.h\fR to avoid any
-potential clash with other POSIX libraries. It can, of course, be renamed or
-aliased as \fBregex.h\fR, which is the "correct" name. It provides two
-structure types, \fIregex_t\fR for compiled internal forms, and
-\fIregmatch_t\fR for returning captured substrings. It also defines some
-constants whose names start with "REG_"; these are used for setting options and
-identifying error codes.
-
-
-.SH COMPILING A PATTERN
-
-The function \fBregcomp()\fR is called to compile a pattern into an
-internal form. The pattern is a C string terminated by a binary zero, and
-is passed in the argument \fIpattern\fR. The \fIpreg\fR argument is a pointer
-to a regex_t structure which is used as a base for storing information about
-the compiled expression.
-
-The argument \fIcflags\fR is either zero, or contains one or more of the bits
-defined by the following macros:
-
-  REG_ICASE
-
-The PCRE_CASELESS option is set when the expression is passed for compilation
-to the native function.
-
-  REG_NEWLINE
-
-The PCRE_MULTILINE option is set when the expression is passed for compilation
-to the native function.
-
-In the absence of these flags, no options are passed to the native function.
-This means the the regex is compiled with PCRE default semantics. In
-particular, the way it handles newline characters in the subject string is the
-Perl way, not the POSIX way. Note that setting PCRE_MULTILINE has only
-\fIsome\fR of the effects specified for REG_NEWLINE. It does not affect the way
-newlines are matched by . (they aren't) or a negative class such as [^a] (they
-are).
-
-The yield of \fBregcomp()\fR is zero on success, and non-zero otherwise. The
-\fIpreg\fR structure is filled in on success, and one member of the structure
-is publicized: \fIre_nsub\fR contains the number of capturing subpatterns in
-the regular expression. Various error codes are defined in the header file.
-
-
-.SH MATCHING A PATTERN
-The function \fBregexec()\fR is called to match a pre-compiled pattern
-\fIpreg\fR against a given \fIstring\fR, which is terminated by a zero byte,
-subject to the options in \fIeflags\fR. These can be:
-
-  REG_NOTBOL
-
-The PCRE_NOTBOL option is set when calling the underlying PCRE matching
-function.
-
-  REG_NOTEOL
-
-The PCRE_NOTEOL option is set when calling the underlying PCRE matching
-function.
-
-The portion of the string that was matched, and also any captured substrings,
-are returned via the \fIpmatch\fR argument, which points to an array of
-\fInmatch\fR structures of type \fIregmatch_t\fR, containing the members
-\fIrm_so\fR and \fIrm_eo\fR. These contain the offset to the first character of
-each substring and the offset to the first character after the end of each
-substring, respectively. The 0th element of the vector relates to the entire
-portion of \fIstring\fR that was matched; subsequent elements relate to the
-capturing subpatterns of the regular expression. Unused entries in the array
-have both structure members set to -1.
-
-A successful match yields a zero return; various error codes are defined in the
-header file, of which REG_NOMATCH is the "expected" failure code.
-
-
-.SH ERROR MESSAGES
-The \fBregerror()\fR function maps a non-zero errorcode from either
-\fBregcomp\fR or \fBregexec\fR to a printable message. If \fIpreg\fR is not
-NULL, the error should have arisen from the use of that structure. A message
-terminated by a binary zero is placed in \fIerrbuf\fR. The length of the
-message, including the zero, is limited to \fIerrbuf_size\fR. The yield of the
-function is the size of buffer needed to hold the whole message.
-
-
-.SH STORAGE
-Compiling a regular expression causes memory to be allocated and associated
-with the \fIpreg\fR structure. The function \fBregfree()\fR frees all such
-memory, after which \fIpreg\fR may no longer be used as a compiled expression.
-
-
-.SH AUTHOR
-Philip Hazel <ph10@cam.ac.uk>
-.br
-University Computing Service,
-.br
-New Museums Site,
-.br
-Cambridge CB2 3QG, England.
-.br
-Phone: +44 1223 334714
-
-Copyright (c) 1997-2000 University of Cambridge.
diff --git a/ext/pcre/pcrelib/doc/pcreposix.html b/ext/pcre/pcrelib/doc/pcreposix.html
deleted file mode 100644
index 9c89478420..0000000000
--- a/ext/pcre/pcrelib/doc/pcreposix.html
+++ /dev/null
@@ -1,191 +0,0 @@
-<HTML>
-<HEAD>
-<TITLE>pcreposix specification</TITLE>
-</HEAD>
-<body bgcolor="#FFFFFF" text="#00005A">
-<H1>pcreposix specification</H1>
-This HTML document has been generated automatically from the original man page.
-If there is any nonsense in it, please consult the man page in case the
-conversion went wrong.
-<UL>
-<LI><A NAME="TOC1" HREF="#SEC1">NAME</A>
-<LI><A NAME="TOC2" HREF="#SEC2">SYNOPSIS</A>
-<LI><A NAME="TOC3" HREF="#SEC3">DESCRIPTION</A>
-<LI><A NAME="TOC4" HREF="#SEC4">COMPILING A PATTERN</A>
-<LI><A NAME="TOC5" HREF="#SEC5">MATCHING A PATTERN</A>
-<LI><A NAME="TOC6" HREF="#SEC6">ERROR MESSAGES</A>
-<LI><A NAME="TOC7" HREF="#SEC7">STORAGE</A>
-<LI><A NAME="TOC8" HREF="#SEC8">AUTHOR</A>
-</UL>
-<LI><A NAME="SEC1" HREF="#TOC1">NAME</A>
-<P>
-pcreposix - POSIX API for Perl-compatible regular expressions.
-</P>
-<LI><A NAME="SEC2" HREF="#TOC1">SYNOPSIS</A>
-<P>
-<B>#include &#60;pcreposix.h&#62;</B>
-</P>
-<P>
-<B>int regcomp(regex_t *<I>preg</I>, const char *<I>pattern</I>,</B>
-<B>int <I>cflags</I>);</B>
-</P>
-<P>
-<B>int regexec(regex_t *<I>preg</I>, const char *<I>string</I>,</B>
-<B>size_t <I>nmatch</I>, regmatch_t <I>pmatch</I>[], int <I>eflags</I>);</B>
-</P>
-<P>
-<B>size_t regerror(int <I>errcode</I>, const regex_t *<I>preg</I>,</B>
-<B>char *<I>errbuf</I>, size_t <I>errbuf_size</I>);</B>
-</P>
-<P>
-<B>void regfree(regex_t *<I>preg</I>);</B>
-</P>
-<LI><A NAME="SEC3" HREF="#TOC1">DESCRIPTION</A>
-<P>
-This set of functions provides a POSIX-style API to the PCRE regular expression
-package. See the <B>pcre</B> documentation for a description of the native API,
-which contains additional functionality.
-</P>
-<P>
-The functions described here are just wrapper functions that ultimately call
-the native API. Their prototypes are defined in the <B>pcreposix.h</B> header
-file, and on Unix systems the library itself is called <B>pcreposix.a</B>, so
-can be accessed by adding <B>-lpcreposix</B> to the command for linking an
-application which uses them. Because the POSIX functions call the native ones,
-it is also necessary to add \fR-lpcre\fR.
-</P>
-<P>
-I have implemented only those option bits that can be reasonably mapped to PCRE
-native options. In addition, the options REG_EXTENDED and REG_NOSUB are defined
-with the value zero. They have no effect, but since programs that are written
-to the POSIX interface often use them, this makes it easier to slot in PCRE as
-a replacement library. Other POSIX options are not even defined.
-</P>
-<P>
-When PCRE is called via these functions, it is only the API that is POSIX-like
-in style. The syntax and semantics of the regular expressions themselves are
-still those of Perl, subject to the setting of various PCRE options, as
-described below.
-</P>
-<P>
-The header for these functions is supplied as <B>pcreposix.h</B> to avoid any
-potential clash with other POSIX libraries. It can, of course, be renamed or
-aliased as <B>regex.h</B>, which is the "correct" name. It provides two
-structure types, <I>regex_t</I> for compiled internal forms, and
-<I>regmatch_t</I> for returning captured substrings. It also defines some
-constants whose names start with "REG_"; these are used for setting options and
-identifying error codes.
-</P>
-<LI><A NAME="SEC4" HREF="#TOC1">COMPILING A PATTERN</A>
-<P>
-The function <B>regcomp()</B> is called to compile a pattern into an
-internal form. The pattern is a C string terminated by a binary zero, and
-is passed in the argument <I>pattern</I>. The <I>preg</I> argument is a pointer
-to a regex_t structure which is used as a base for storing information about
-the compiled expression.
-</P>
-<P>
-The argument <I>cflags</I> is either zero, or contains one or more of the bits
-defined by the following macros:
-</P>
-<P>
-<PRE>
-  REG_ICASE
-</PRE>
-</P>
-<P>
-The PCRE_CASELESS option is set when the expression is passed for compilation
-to the native function.
-</P>
-<P>
-<PRE>
-  REG_NEWLINE
-</PRE>
-</P>
-<P>
-The PCRE_MULTILINE option is set when the expression is passed for compilation
-to the native function.
-</P>
-<P>
-In the absence of these flags, no options are passed to the native function.
-This means the the regex is compiled with PCRE default semantics. In
-particular, the way it handles newline characters in the subject string is the
-Perl way, not the POSIX way. Note that setting PCRE_MULTILINE has only
-<I>some</I> of the effects specified for REG_NEWLINE. It does not affect the way
-newlines are matched by . (they aren't) or a negative class such as [^a] (they
-are).
-</P>
-<P>
-The yield of <B>regcomp()</B> is zero on success, and non-zero otherwise. The
-<I>preg</I> structure is filled in on success, and one member of the structure
-is publicized: <I>re_nsub</I> contains the number of capturing subpatterns in
-the regular expression. Various error codes are defined in the header file.
-</P>
-<LI><A NAME="SEC5" HREF="#TOC1">MATCHING A PATTERN</A>
-<P>
-The function <B>regexec()</B> is called to match a pre-compiled pattern
-<I>preg</I> against a given <I>string</I>, which is terminated by a zero byte,
-subject to the options in <I>eflags</I>. These can be:
-</P>
-<P>
-<PRE>
-  REG_NOTBOL
-</PRE>
-</P>
-<P>
-The PCRE_NOTBOL option is set when calling the underlying PCRE matching
-function.
-</P>
-<P>
-<PRE>
-  REG_NOTEOL
-</PRE>
-</P>
-<P>
-The PCRE_NOTEOL option is set when calling the underlying PCRE matching
-function.
-</P>
-<P>
-The portion of the string that was matched, and also any captured substrings,
-are returned via the <I>pmatch</I> argument, which points to an array of
-<I>nmatch</I> structures of type <I>regmatch_t</I>, containing the members
-<I>rm_so</I> and <I>rm_eo</I>. These contain the offset to the first character of
-each substring and the offset to the first character after the end of each
-substring, respectively. The 0th element of the vector relates to the entire
-portion of <I>string</I> that was matched; subsequent elements relate to the
-capturing subpatterns of the regular expression. Unused entries in the array
-have both structure members set to -1.
-</P>
-<P>
-A successful match yields a zero return; various error codes are defined in the
-header file, of which REG_NOMATCH is the "expected" failure code.
-</P>
-<LI><A NAME="SEC6" HREF="#TOC1">ERROR MESSAGES</A>
-<P>
-The <B>regerror()</B> function maps a non-zero errorcode from either
-<B>regcomp</B> or <B>regexec</B> to a printable message. If <I>preg</I> is not
-NULL, the error should have arisen from the use of that structure. A message
-terminated by a binary zero is placed in <I>errbuf</I>. The length of the
-message, including the zero, is limited to <I>errbuf_size</I>. The yield of the
-function is the size of buffer needed to hold the whole message.
-</P>
-<LI><A NAME="SEC7" HREF="#TOC1">STORAGE</A>
-<P>
-Compiling a regular expression causes memory to be allocated and associated
-with the <I>preg</I> structure. The function <B>regfree()</B> frees all such
-memory, after which <I>preg</I> may no longer be used as a compiled expression.
-</P>
-<LI><A NAME="SEC8" HREF="#TOC1">AUTHOR</A>
-<P>
-Philip Hazel &#60;ph10@cam.ac.uk&#62;
-<BR>
-University Computing Service,
-<BR>
-New Museums Site,
-<BR>
-Cambridge CB2 3QG, England.
-<BR>
-Phone: +44 1223 334714
-</P>
-<P>
-Copyright (c) 1997-2000 University of Cambridge.
diff --git a/ext/pcre/pcrelib/doc/pcreposix.txt b/ext/pcre/pcrelib/doc/pcreposix.txt
deleted file mode 100644
index 2d76f7cdcc..0000000000
--- a/ext/pcre/pcrelib/doc/pcreposix.txt
+++ /dev/null
@@ -1,159 +0,0 @@
-NAME
-     pcreposix - POSIX API for  Perl-compatible  regular  expres-
-     sions.
-
-
-
-SYNOPSIS
-     #include <pcreposix.h>
-
-     int regcomp(regex_t *preg, const char *pattern,
-          int cflags);
-
-     int regexec(regex_t *preg, const char *string,
-          size_t nmatch, regmatch_t pmatch[], int eflags);
-
-     size_t regerror(int errcode, const regex_t *preg,
-          char *errbuf, size_t errbuf_size);
-
-     void regfree(regex_t *preg);
-
-
-
-DESCRIPTION
-     This set of functions provides a POSIX-style API to the PCRE
-     regular expression package. See the pcre documentation for a
-     description of the native  API,  which  contains  additional
-     functionality.
-
-     The functions described here are just wrapper functions that
-     ultimately call the native API. Their prototypes are defined
-     in the pcreposix.h header file,  and  on  Unix  systems  the
-     library  itself is called pcreposix.a, so can be accessed by
-     adding -lpcreposix to the command for linking an application
-     which uses them. Because the POSIX functions call the native
-     ones, it is also necessary to add -lpcre.
-
-     I have implemented only those option bits that can  be  rea-
-     sonably  mapped  to  PCRE  native  options. In addition, the
-     options REG_EXTENDED and  REG_NOSUB  are  defined  with  the
-     value zero. They have no effect, but since programs that are
-     written to the POSIX interface often use them, this makes it
-     easier to slot in PCRE as a replacement library. Other POSIX
-     options are not even defined.
-
-     When PCRE is called via these functions, it is only the  API
-     that is POSIX-like in style. The syntax and semantics of the
-     regular expressions themselves are still those of Perl, sub-
-     ject  to  the  setting of various PCRE options, as described
-     below.
-
-     The header for these functions is supplied as pcreposix.h to
-     avoid  any  potential  clash  with other POSIX libraries. It
-     can, of course, be renamed or aliased as regex.h,  which  is
-     the "correct" name. It provides two structure types, regex_t
-     for compiled internal forms, and  regmatch_t  for  returning
-     captured  substrings.  It  also defines some constants whose
-     names start with "REG_"; these are used for setting  options
-     and identifying error codes.
-
-
-
-COMPILING A PATTERN
-     The function regcomp() is called to compile a  pattern  into
-     an  internal form. The pattern is a C string terminated by a
-     binary zero, and is passed in the argument pattern. The preg
-     argument  is  a pointer to a regex_t structure which is used
-     as a base for storing information about the compiled expres-
-     sion.
-
-     The argument cflags is either zero, or contains one or  more
-     of the bits defined by the following macros:
-
-       REG_ICASE
-
-     The PCRE_CASELESS option  is  set  when  the  expression  is
-     passed for compilation to the native function.
-
-       REG_NEWLINE
-
-     The PCRE_MULTILINE option is  set  when  the  expression  is
-     passed for compilation to the native function.
-
-     In the absence of these flags, no options are passed to  the
-     native  function.  This means the the regex is compiled with
-     PCRE default semantics. In particular, the  way  it  handles
-     newline  characters  in  the subject string is the Perl way,
-     not the POSIX way. Note that setting PCRE_MULTILINE has only
-     some  of  the effects specified for REG_NEWLINE. It does not
-     affect the way newlines are matched by . (they aren't) or  a
-     negative class such as [^a] (they are).
-
-     The yield of regcomp() is zero on success, and non-zero oth-
-     erwise.  The preg structure is filled in on success, and one
-     member of the structure is publicized: re_nsub contains  the
-     number  of  capturing subpatterns in the regular expression.
-     Various error codes are defined in the header file.
-
-
-
-MATCHING A PATTERN
-     The function regexec() is called  to  match  a  pre-compiled
-     pattern  preg against a given string, which is terminated by
-     a zero byte, subject to the options in eflags. These can be:
-
-       REG_NOTBOL
-
-     The PCRE_NOTBOL option is set when  calling  the  underlying
-     PCRE matching function.
-
-       REG_NOTEOL
-
-     The PCRE_NOTEOL option is set when  calling  the  underlying
-     PCRE matching function.
-
-     The portion of the string that was  matched,  and  also  any
-     captured  substrings,  are returned via the pmatch argument,
-     which points to  an  array  of  nmatch  structures  of  type
-     regmatch_t,  containing  the  members rm_so and rm_eo. These
-     contain the offset to the first character of each  substring
-     and  the offset to the first character after the end of each
-     substring, respectively.  The  0th  element  of  the  vector
-     relates  to  the  entire portion of string that was matched;
-     subsequent elements relate to the capturing  subpatterns  of
-     the  regular  expression.  Unused  entries in the array have
-     both structure members set to -1.
-
-     A successful match yields a zero return; various error codes
-     are  defined in the header file, of which REG_NOMATCH is the
-     "expected" failure code.
-
-
-
-ERROR MESSAGES
-     The regerror()  function  maps  a  non-zero  errorcode  from
-     either regcomp or regexec to a printable message. If preg is
-     not NULL, the error should have arisen from the use of  that
-     structure.  A  message terminated by a binary zero is placed
-     in errbuf. The length of the message, including the zero, is
-     limited  to  errbuf_size.  The  yield of the function is the
-     size of buffer needed to hold the whole message.
-
-
-
-STORAGE
-     Compiling a regular expression causes memory to be allocated
-     and  associated  with  the preg structure. The function reg-
-     free() frees all such memory, after which preg may no longer
-     be used as a compiled expression.
-
-
-
-AUTHOR
-     Philip Hazel <ph10@cam.ac.uk>
-     University Computing Service,
-     New Museums Site,
-     Cambridge CB2 3QG, England.
-     Phone: +44 1223 334714
-
-     Copyright (c) 1997-2000 University of Cambridge.
diff --git a/ext/pcre/pcrelib/doc/pcretest.txt b/ext/pcre/pcrelib/doc/pcretest.txt
deleted file mode 100644
index add2979f14..0000000000
--- a/ext/pcre/pcrelib/doc/pcretest.txt
+++ /dev/null
@@ -1,246 +0,0 @@
-The pcretest program
---------------------
-
-This program is intended for testing PCRE, but it can also be used for
-experimenting with regular expressions.
-
-If it is given two filename arguments, it reads from the first and writes to
-the second. If it is given only one filename argument, it reads from that file
-and writes to stdout. Otherwise, it reads from stdin and writes to stdout, and
-prompts for each line of input, using "re>" to prompt for regular expressions,
-and "data>" to prompt for data lines.
-
-The program handles any number of sets of input on a single input file. Each
-set starts with a regular expression, and continues with any number of data
-lines to be matched against the pattern. An empty line signals the end of the
-data lines, at which point a new regular expression is read. The regular
-expressions are given enclosed in any non-alphameric delimiters other than
-backslash, for example
-
-  /(a|bc)x+yz/
-
-White space before the initial delimiter is ignored. A regular expression may
-be continued over several input lines, in which case the newline characters are
-included within it. See the test input files in the testdata directory for many
-examples. It is possible to include the delimiter within the pattern by
-escaping it, for example
-
-  /abc\/def/
-
-If you do so, the escape and the delimiter form part of the pattern, but since
-delimiters are always non-alphameric, this does not affect its interpretation.
-If the terminating delimiter is immediately followed by a backslash, for
-example,
-
-  /abc/\
-
-then a backslash is added to the end of the pattern. This is done to provide a
-way of testing the error condition that arises if a pattern finishes with a
-backslash, because
-
-  /abc\/
-
-is interpreted as the first line of a pattern that starts with "abc/", causing
-pcretest to read the next line as a continuation of the regular expression.
-
-
-PATTERN MODIFIERS
------------------
-
-The pattern may be followed by i, m, s, or x to set the PCRE_CASELESS,
-PCRE_MULTILINE, PCRE_DOTALL, or PCRE_EXTENDED options, respectively. For
-example:
-
-  /caseless/i
-
-These modifier letters have the same effect as they do in Perl. There are
-others which set PCRE options that do not correspond to anything in Perl: /A,
-/E, and /X set PCRE_ANCHORED, PCRE_DOLLAR_ENDONLY, and PCRE_EXTRA respectively.
-
-Searching for all possible matches within each subject string can be requested
-by the /g or /G modifier. After finding a match, PCRE is called again to search
-the remainder of the subject string. The difference between /g and /G is that
-the former uses the startoffset argument to pcre_exec() to start searching at
-a new point within the entire string (which is in effect what Perl does),
-whereas the latter passes over a shortened substring. This makes a difference
-to the matching process if the pattern begins with a lookbehind assertion
-(including \b or \B).
-
-If any call to pcre_exec() in a /g or /G sequence matches an empty string, the
-next call is done with the PCRE_NOTEMPTY and PCRE_ANCHORED flags set in order
-to search for another, non-empty, match at the same point. If this second match
-fails, the start offset is advanced by one, and the normal match is retried.
-This imitates the way Perl handles such cases when using the /g modifier or the
-split() function.
-
-There are a number of other modifiers for controlling the way pcretest
-operates.
-
-The /+ modifier requests that as well as outputting the substring that matched
-the entire pattern, pcretest should in addition output the remainder of the
-subject string. This is useful for tests where the subject contains multiple
-copies of the same substring.
-
-The /L modifier must be followed directly by the name of a locale, for example,
-
-  /pattern/Lfr
-
-For this reason, it must be the last modifier letter. The given locale is set,
-pcre_maketables() is called to build a set of character tables for the locale,
-and this is then passed to pcre_compile() when compiling the regular
-expression. Without an /L modifier, NULL is passed as the tables pointer; that
-is, /L applies only to the expression on which it appears.
-
-The /I modifier requests that pcretest output information about the compiled
-expression (whether it is anchored, has a fixed first character, and so on). It
-does this by calling pcre_fullinfo() after compiling an expression, and
-outputting the information it gets back. If the pattern is studied, the results
-of that are also output.
-
-The /D modifier is a PCRE debugging feature, which also assumes /I. It causes
-the internal form of compiled regular expressions to be output after
-compilation.
-
-The /S modifier causes pcre_study() to be called after the expression has been
-compiled, and the results used when the expression is matched.
-
-The /M modifier causes the size of memory block used to hold the compiled
-pattern to be output.
-
-The /P modifier causes pcretest to call PCRE via the POSIX wrapper API rather
-than its native API. When this is done, all other modifiers except /i, /m, and
-/+ are ignored. REG_ICASE is set if /i is present, and REG_NEWLINE is set if /m
-is present. The wrapper functions force PCRE_DOLLAR_ENDONLY always, and
-PCRE_DOTALL unless REG_NEWLINE is set.
-
-The /8 modifier causes pcretest to call PCRE with the PCRE_UTF8 option set.
-This turns on the (currently incomplete) support for UTF-8 character handling
-in PCRE, provided that it was compiled with this support enabled. This modifier
-also causes any non-printing characters in output strings to be printed using
-the \x{hh...} notation if they are valid UTF-8 sequences.
-
-
-DATA LINES
-----------
-
-Before each data line is passed to pcre_exec(), leading and trailing whitespace
-is removed, and it is then scanned for \ escapes. The following are recognized:
-
-  \a         alarm (= BEL)
-  \b         backspace
-  \e         escape
-  \f         formfeed
-  \n         newline
-  \r         carriage return
-  \t         tab
-  \v         vertical tab
-  \nnn       octal character (up to 3 octal digits)
-  \xhh       hexadecimal character (up to 2 hex digits)
-  \x{hh...}  hexadecimal UTF-8 character
-
-  \A         pass the PCRE_ANCHORED option to pcre_exec()
-  \B         pass the PCRE_NOTBOL option to pcre_exec()
-  \Cdd       call pcre_copy_substring() for substring dd after a successful
-               match (any decimal number less than 32)
-  \Gdd       call pcre_get_substring() for substring dd after a successful
-               match (any decimal number less than 32)
-  \L         call pcre_get_substringlist() after a successful match
-  \N         pass the PCRE_NOTEMPTY option to pcre_exec()
-  \Odd       set the size of the output vector passed to pcre_exec() to dd
-               (any number of decimal digits)
-  \Z         pass the PCRE_NOTEOL option to pcre_exec()
-
-A backslash followed by anything else just escapes the anything else. If the
-very last character is a backslash, it is ignored. This gives a way of passing
-an empty line as data, since a real empty line terminates the data input.
-
-If /P was present on the regex, causing the POSIX wrapper API to be used, only
-\B, and \Z have any effect, causing REG_NOTBOL and REG_NOTEOL to be passed to
-regexec() respectively.
-
-The use of \x{hh...} to represent UTF-8 characters is not dependent on the use
-of the /8 modifier on the pattern. It is recognized always. There may be any
-number of hexadecimal digits inside the braces. The result is from one to six
-bytes, encoded according to the UTF-8 rules.
-
-
-OUTPUT FROM PCRETEST
---------------------
-
-When a match succeeds, pcretest outputs the list of captured substrings that
-pcre_exec() returns, starting with number 0 for the string that matched the
-whole pattern. Here is an example of an interactive pcretest run.
-
-  $ pcretest
-  PCRE version 2.06 08-Jun-1999
-
-    re> /^abc(\d+)/
-  data> abc123
-   0: abc123
-   1: 123
-  data> xyz
-  No match
-
-If the strings contain any non-printing characters, they are output as \0x
-escapes, or as \x{...} escapes if the /8 modifier was present on the pattern.
-If the pattern has the /+ modifier, then the output for substring 0 is followed
-by the the rest of the subject string, identified by "0+" like this:
-
-    re> /cat/+
-  data> cataract
-   0: cat
-   0+ aract
-
-If the pattern has the /g or /G modifier, the results of successive matching
-attempts are output in sequence, like this:
-
-    re> /\Bi(\w\w)/g
-  data> Mississippi
-   0: iss
-   1: ss
-   0: iss
-   1: ss
-   0: ipp
-   1: pp
-
-"No match" is output only if the first match attempt fails.
-
-If any of \C, \G, or \L are present in a data line that is successfully
-matched, the substrings extracted by the convenience functions are output with
-C, G, or L after the string number instead of a colon. This is in addition to
-the normal full list. The string length (that is, the return from the
-extraction function) is given in parentheses after each string for \C and \G.
-
-Note that while patterns can be continued over several lines (a plain ">"
-prompt is used for continuations), data lines may not. However newlines can be
-included in data by means of the \n escape.
-
-
-COMMAND LINE OPTIONS
---------------------
-
-If the -p option is given to pcretest, it is equivalent to adding /P to each
-regular expression: the POSIX wrapper API is used to call PCRE. None of the
-following flags has any effect in this case.
-
-If the option -d is given to pcretest, it is equivalent to adding /D to each
-regular expression: the internal form is output after compilation.
-
-If the option -i is given to pcretest, it is equivalent to adding /I to each
-regular expression: information about the compiled pattern is given after
-compilation.
-
-If the option -m is given to pcretest, it outputs the size of each compiled
-pattern after it has been compiled. It is equivalent to adding /M to each
-regular expression. For compatibility with earlier versions of pcretest, -s is
-a synonym for -m.
-
-If the -t option is given, each compile, study, and match is run 20000 times
-while being timed, and the resulting time per compile or match is output in
-milliseconds. Do not set -t with -m, because you will then get the size output
-20000 times and the timing will be distorted. If you want to change the number
-of repetitions used for timing, edit the definition of LOOPREPEAT at the top of
-pcretest.c
-
-Philip Hazel <ph10@cam.ac.uk>
-August 2000
diff --git a/ext/pcre/pcrelib/doc/perltest.txt b/ext/pcre/pcrelib/doc/perltest.txt
deleted file mode 100644
index 5a404016b5..0000000000
--- a/ext/pcre/pcrelib/doc/perltest.txt
+++ /dev/null
@@ -1,29 +0,0 @@
-The perltest program
---------------------
-
-The perltest program tests Perl's regular expressions; it has the same
-specification as pcretest, and so can be given identical input, except that
-input patterns can be followed only by Perl's lower case modifiers and /+ (as
-used by pcretest), which is recognized and handled by the program.
-
-The data lines are processed as Perl double-quoted strings, so if they contain
-" \ $ or @ characters, these have to be escaped. For this reason, all such
-characters in testinput1 and testinput3 are escaped so that they can be used
-for perltest as well as for pcretest, and the special upper case modifiers such
-as /A that pcretest recognizes are not used in these files. The output should
-be identical, apart from the initial identifying banner.
-
-For testing UTF-8 features, an alternative form of perltest, called perltest8,
-is supplied. This requires Perl 5.6 or higher. It recognizes the special
-modifier /8 that pcretest uses to invoke UTF-8 functionality. The testinput5
-file can be fed to perltest8.
-
-The testinput2 and testinput4 files are not suitable for feeding to perltest,
-since they do make use of the special upper case modifiers and escapes that
-pcretest uses to test some features of PCRE. The first of these files also
-contains malformed regular expressions, in order to check that PCRE diagnoses
-them correctly. Similarly, testinput6 tests UTF-8 features that do not relate
-to Perl.
-
-Philip Hazel <ph10@cam.ac.uk>
-August 2000