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diff --git a/pod/perldelta4.pod b/pod/perldelta4.pod new file mode 100644 index 0000000000..9443f386d9 --- /dev/null +++ b/pod/perldelta4.pod @@ -0,0 +1,1609 @@ +=head1 NAME + +perldelta - what's new for perl5.004 + +=head1 DESCRIPTION + +This document describes differences between the 5.003 release (as +documented in I<Programming Perl>, second edition--the Camel Book) and +this one. + +=head1 Supported Environments + +Perl5.004 builds out of the box on Unix, Plan 9, LynxOS, VMS, OS/2, +QNX, AmigaOS, and Windows NT. Perl runs on Windows 95 as well, but it +cannot be built there, for lack of a reasonable command interpreter. + +=head1 Core Changes + +Most importantly, many bugs were fixed, including several security +problems. See the F<Changes> file in the distribution for details. + +=head2 List assignment to %ENV works + +C<%ENV = ()> and C<%ENV = @list> now work as expected (except on VMS +where it generates a fatal error). + +=head2 "Can't locate Foo.pm in @INC" error now lists @INC + +=head2 Compilation option: Binary compatibility with 5.003 + +There is a new Configure question that asks if you want to maintain +binary compatibility with Perl 5.003. If you choose binary +compatibility, you do not have to recompile your extensions, but you +might have symbol conflicts if you embed Perl in another application, +just as in the 5.003 release. By default, binary compatibility +is preserved at the expense of symbol table pollution. + +=head2 $PERL5OPT environment variable + +You may now put Perl options in the $PERL5OPT environment variable. +Unless Perl is running with taint checks, it will interpret this +variable as if its contents had appeared on a "#!perl" line at the +beginning of your script, except that hyphens are optional. PERL5OPT +may only be used to set the following switches: B<-[DIMUdmw]>. + +=head2 Limitations on B<-M>, B<-m>, and B<-T> options + +The C<-M> and C<-m> options are no longer allowed on the C<#!> line of +a script. If a script needs a module, it should invoke it with the +C<use> pragma. + +The B<-T> option is also forbidden on the C<#!> line of a script, +unless it was present on the Perl command line. Due to the way C<#!> +works, this usually means that B<-T> must be in the first argument. +Thus: + + #!/usr/bin/perl -T -w + +will probably work for an executable script invoked as C<scriptname>, +while: + + #!/usr/bin/perl -w -T + +will probably fail under the same conditions. (Non-Unix systems will +probably not follow this rule.) But C<perl scriptname> is guaranteed +to fail, since then there is no chance of B<-T> being found on the +command line before it is found on the C<#!> line. + +=head2 More precise warnings + +If you removed the B<-w> option from your Perl 5.003 scripts because it +made Perl too verbose, we recommend that you try putting it back when +you upgrade to Perl 5.004. Each new perl version tends to remove some +undesirable warnings, while adding new warnings that may catch bugs in +your scripts. + +=head2 Deprecated: Inherited C<AUTOLOAD> for non-methods + +Before Perl 5.004, C<AUTOLOAD> functions were looked up as methods +(using the C<@ISA> hierarchy), even when the function to be autoloaded +was called as a plain function (e.g. C<Foo::bar()>), not a method +(e.g. C<Foo-E<gt>bar()> or C<$obj-E<gt>bar()>). + +Perl 5.005 will use method lookup only for methods' C<AUTOLOAD>s. +However, there is a significant base of existing code that may be using +the old behavior. So, as an interim step, Perl 5.004 issues an optional +warning when a non-method uses an inherited C<AUTOLOAD>. + +The simple rule is: Inheritance will not work when autoloading +non-methods. The simple fix for old code is: In any module that used to +depend on inheriting C<AUTOLOAD> for non-methods from a base class named +C<BaseClass>, execute C<*AUTOLOAD = \&BaseClass::AUTOLOAD> during startup. + +=head2 Previously deprecated %OVERLOAD is no longer usable + +Using %OVERLOAD to define overloading was deprecated in 5.003. +Overloading is now defined using the overload pragma. %OVERLOAD is +still used internally but should not be used by Perl scripts. See +L<overload> for more details. + +=head2 Subroutine arguments created only when they're modified + +In Perl 5.004, nonexistent array and hash elements used as subroutine +parameters are brought into existence only if they are actually +assigned to (via C<@_>). + +Earlier versions of Perl vary in their handling of such arguments. +Perl versions 5.002 and 5.003 always brought them into existence. +Perl versions 5.000 and 5.001 brought them into existence only if +they were not the first argument (which was almost certainly a bug). +Earlier versions of Perl never brought them into existence. + +For example, given this code: + + undef @a; undef %a; + sub show { print $_[0] }; + sub change { $_[0]++ }; + show($a[2]); + change($a{b}); + +After this code executes in Perl 5.004, $a{b} exists but $a[2] does +not. In Perl 5.002 and 5.003, both $a{b} and $a[2] would have existed +(but $a[2]'s value would have been undefined). + +=head2 Group vector changeable with C<$)> + +The C<$)> special variable has always (well, in Perl 5, at least) +reflected not only the current effective group, but also the group list +as returned by the C<getgroups()> C function (if there is one). +However, until this release, there has not been a way to call the +C<setgroups()> C function from Perl. + +In Perl 5.004, assigning to C<$)> is exactly symmetrical with examining +it: The first number in its string value is used as the effective gid; +if there are any numbers after the first one, they are passed to the +C<setgroups()> C function (if there is one). + +=head2 Fixed parsing of $$<digit>, &$<digit>, etc. + +Perl versions before 5.004 misinterpreted any type marker followed by +"$" and a digit. For example, "$$0" was incorrectly taken to mean +"${$}0" instead of "${$0}". This bug is (mostly) fixed in Perl 5.004. + +However, the developers of Perl 5.004 could not fix this bug completely, +because at least two widely-used modules depend on the old meaning of +"$$0" in a string. So Perl 5.004 still interprets "$$<digit>" in the +old (broken) way inside strings; but it generates this message as a +warning. And in Perl 5.005, this special treatment will cease. + +=head2 Fixed localization of $<digit>, $&, etc. + +Perl versions before 5.004 did not always properly localize the +regex-related special variables. Perl 5.004 does localize them, as +the documentation has always said it should. This may result in $1, +$2, etc. no longer being set where existing programs use them. + +=head2 No resetting of $. on implicit close + +The documentation for Perl 5.0 has always stated that C<$.> is I<not> +reset when an already-open file handle is reopened with no intervening +call to C<close>. Due to a bug, perl versions 5.000 through 5.003 +I<did> reset C<$.> under that circumstance; Perl 5.004 does not. + +=head2 C<wantarray> may return undef + +The C<wantarray> operator returns true if a subroutine is expected to +return a list, and false otherwise. In Perl 5.004, C<wantarray> can +also return the undefined value if a subroutine's return value will +not be used at all, which allows subroutines to avoid a time-consuming +calculation of a return value if it isn't going to be used. + +=head2 C<eval EXPR> determines value of EXPR in scalar context + +Perl (version 5) used to determine the value of EXPR inconsistently, +sometimes incorrectly using the surrounding context for the determination. +Now, the value of EXPR (before being parsed by eval) is always determined in +a scalar context. Once parsed, it is executed as before, by providing +the context that the scope surrounding the eval provided. This change +makes the behavior Perl4 compatible, besides fixing bugs resulting from +the inconsistent behavior. This program: + + @a = qw(time now is time); + print eval @a; + print '|', scalar eval @a; + +used to print something like "timenowis881399109|4", but now (and in perl4) +prints "4|4". + +=head2 Changes to tainting checks + +A bug in previous versions may have failed to detect some insecure +conditions when taint checks are turned on. (Taint checks are used +in setuid or setgid scripts, or when explicitly turned on with the +C<-T> invocation option.) Although it's unlikely, this may cause a +previously-working script to now fail -- which should be construed +as a blessing, since that indicates a potentially-serious security +hole was just plugged. + +The new restrictions when tainting include: + +=over + +=item No glob() or <*> + +These operators may spawn the C shell (csh), which cannot be made +safe. This restriction will be lifted in a future version of Perl +when globbing is implemented without the use of an external program. + +=item No spawning if tainted $CDPATH, $ENV, $BASH_ENV + +These environment variables may alter the behavior of spawned programs +(especially shells) in ways that subvert security. So now they are +treated as dangerous, in the manner of $IFS and $PATH. + +=item No spawning if tainted $TERM doesn't look like a terminal name + +Some termcap libraries do unsafe things with $TERM. However, it would be +unnecessarily harsh to treat all $TERM values as unsafe, since only shell +metacharacters can cause trouble in $TERM. So a tainted $TERM is +considered to be safe if it contains only alphanumerics, underscores, +dashes, and colons, and unsafe if it contains other characters (including +whitespace). + +=back + +=head2 New Opcode module and revised Safe module + +A new Opcode module supports the creation, manipulation and +application of opcode masks. The revised Safe module has a new API +and is implemented using the new Opcode module. Please read the new +Opcode and Safe documentation. + +=head2 Embedding improvements + +In older versions of Perl it was not possible to create more than one +Perl interpreter instance inside a single process without leaking like a +sieve and/or crashing. The bugs that caused this behavior have all been +fixed. However, you still must take care when embedding Perl in a C +program. See the updated perlembed manpage for tips on how to manage +your interpreters. + +=head2 Internal change: FileHandle class based on IO::* classes + +File handles are now stored internally as type IO::Handle. The +FileHandle module is still supported for backwards compatibility, but +it is now merely a front end to the IO::* modules -- specifically, +IO::Handle, IO::Seekable, and IO::File. We suggest, but do not +require, that you use the IO::* modules in new code. + +In harmony with this change, C<*GLOB{FILEHANDLE}> is now just a +backward-compatible synonym for C<*GLOB{IO}>. + +=head2 Internal change: PerlIO abstraction interface + +It is now possible to build Perl with AT&T's sfio IO package +instead of stdio. See L<perlapio> for more details, and +the F<INSTALL> file for how to use it. + +=head2 New and changed syntax + +=over + +=item $coderef->(PARAMS) + +A subroutine reference may now be suffixed with an arrow and a +(possibly empty) parameter list. This syntax denotes a call of the +referenced subroutine, with the given parameters (if any). + +This new syntax follows the pattern of S<C<$hashref-E<gt>{FOO}>> and +S<C<$aryref-E<gt>[$foo]>>: You may now write S<C<&$subref($foo)>> as +S<C<$subref-E<gt>($foo)>>. All of these arrow terms may be chained; +thus, S<C<&{$table-E<gt>{FOO}}($bar)>> may now be written +S<C<$table-E<gt>{FOO}-E<gt>($bar)>>. + +=back + +=head2 New and changed builtin constants + +=over + +=item __PACKAGE__ + +The current package name at compile time, or the undefined value if +there is no current package (due to a C<package;> directive). Like +C<__FILE__> and C<__LINE__>, C<__PACKAGE__> does I<not> interpolate +into strings. + +=back + +=head2 New and changed builtin variables + +=over + +=item $^E + +Extended error message on some platforms. (Also known as +$EXTENDED_OS_ERROR if you C<use English>). + +=item $^H + +The current set of syntax checks enabled by C<use strict>. See the +documentation of C<strict> for more details. Not actually new, but +newly documented. +Because it is intended for internal use by Perl core components, +there is no C<use English> long name for this variable. + +=item $^M + +By default, running out of memory it is not trappable. However, if +compiled for this, Perl may use the contents of C<$^M> as an emergency +pool after die()ing with this message. Suppose that your Perl were +compiled with -DPERL_EMERGENCY_SBRK and used Perl's malloc. Then + + $^M = 'a' x (1<<16); + +would allocate a 64K buffer for use when in emergency. +See the F<INSTALL> file for information on how to enable this option. +As a disincentive to casual use of this advanced feature, +there is no C<use English> long name for this variable. + +=back + +=head2 New and changed builtin functions + +=over + +=item delete on slices + +This now works. (e.g. C<delete @ENV{'PATH', 'MANPATH'}>) + +=item flock + +is now supported on more platforms, prefers fcntl to lockf when +emulating, and always flushes before (un)locking. + +=item printf and sprintf + +Perl now implements these functions itself; it doesn't use the C +library function sprintf() any more, except for floating-point +numbers, and even then only known flags are allowed. As a result, it +is now possible to know which conversions and flags will work, and +what they will do. + +The new conversions in Perl's sprintf() are: + + %i a synonym for %d + %p a pointer (the address of the Perl value, in hexadecimal) + %n special: *stores* the number of characters output so far + into the next variable in the parameter list + +The new flags that go between the C<%> and the conversion are: + + # prefix octal with "0", hex with "0x" + h interpret integer as C type "short" or "unsigned short" + V interpret integer as Perl's standard integer type + +Also, where a number would appear in the flags, an asterisk ("*") may +be used instead, in which case Perl uses the next item in the +parameter list as the given number (that is, as the field width or +precision). If a field width obtained through "*" is negative, it has +the same effect as the '-' flag: left-justification. + +See L<perlfunc/sprintf> for a complete list of conversion and flags. + +=item keys as an lvalue + +As an lvalue, C<keys> allows you to increase the number of hash buckets +allocated for the given hash. This can gain you a measure of efficiency if +you know the hash is going to get big. (This is similar to pre-extending +an array by assigning a larger number to $#array.) If you say + + keys %hash = 200; + +then C<%hash> will have at least 200 buckets allocated for it. These +buckets will be retained even if you do C<%hash = ()>; use C<undef +%hash> if you want to free the storage while C<%hash> is still in scope. +You can't shrink the number of buckets allocated for the hash using +C<keys> in this way (but you needn't worry about doing this by accident, +as trying has no effect). + +=item my() in Control Structures + +You can now use my() (with or without the parentheses) in the control +expressions of control structures such as: + + while (defined(my $line = <>)) { + $line = lc $line; + } continue { + print $line; + } + + if ((my $answer = <STDIN>) =~ /^y(es)?$/i) { + user_agrees(); + } elsif ($answer =~ /^n(o)?$/i) { + user_disagrees(); + } else { + chomp $answer; + die "`$answer' is neither `yes' nor `no'"; + } + +Also, you can declare a foreach loop control variable as lexical by +preceding it with the word "my". For example, in: + + foreach my $i (1, 2, 3) { + some_function(); + } + +$i is a lexical variable, and the scope of $i extends to the end of +the loop, but not beyond it. + +Note that you still cannot use my() on global punctuation variables +such as $_ and the like. + +=item pack() and unpack() + +A new format 'w' represents a BER compressed integer (as defined in +ASN.1). Its format is a sequence of one or more bytes, each of which +provides seven bits of the total value, with the most significant +first. Bit eight of each byte is set, except for the last byte, in +which bit eight is clear. + +If 'p' or 'P' are given undef as values, they now generate a NULL +pointer. + +Both pack() and unpack() now fail when their templates contain invalid +types. (Invalid types used to be ignored.) + +=item sysseek() + +The new sysseek() operator is a variant of seek() that sets and gets the +file's system read/write position, using the lseek(2) system call. It is +the only reliable way to seek before using sysread() or syswrite(). Its +return value is the new position, or the undefined value on failure. + +=item use VERSION + +If the first argument to C<use> is a number, it is treated as a version +number instead of a module name. If the version of the Perl interpreter +is less than VERSION, then an error message is printed and Perl exits +immediately. Because C<use> occurs at compile time, this check happens +immediately during the compilation process, unlike C<require VERSION>, +which waits until runtime for the check. This is often useful if you +need to check the current Perl version before C<use>ing library modules +which have changed in incompatible ways from older versions of Perl. +(We try not to do this more than we have to.) + +=item use Module VERSION LIST + +If the VERSION argument is present between Module and LIST, then the +C<use> will call the VERSION method in class Module with the given +version as an argument. The default VERSION method, inherited from +the UNIVERSAL class, croaks if the given version is larger than the +value of the variable $Module::VERSION. (Note that there is not a +comma after VERSION!) + +This version-checking mechanism is similar to the one currently used +in the Exporter module, but it is faster and can be used with modules +that don't use the Exporter. It is the recommended method for new +code. + +=item prototype(FUNCTION) + +Returns the prototype of a function as a string (or C<undef> if the +function has no prototype). FUNCTION is a reference to or the name of the +function whose prototype you want to retrieve. +(Not actually new; just never documented before.) + +=item srand + +The default seed for C<srand>, which used to be C<time>, has been changed. +Now it's a heady mix of difficult-to-predict system-dependent values, +which should be sufficient for most everyday purposes. + +Previous to version 5.004, calling C<rand> without first calling C<srand> +would yield the same sequence of random numbers on most or all machines. +Now, when perl sees that you're calling C<rand> and haven't yet called +C<srand>, it calls C<srand> with the default seed. You should still call +C<srand> manually if your code might ever be run on a pre-5.004 system, +of course, or if you want a seed other than the default. + +=item $_ as Default + +Functions documented in the Camel to default to $_ now in +fact do, and all those that do are so documented in L<perlfunc>. + +=item C<m//gc> does not reset search position on failure + +The C<m//g> match iteration construct has always reset its target +string's search position (which is visible through the C<pos> operator) +when a match fails; as a result, the next C<m//g> match after a failure +starts again at the beginning of the string. With Perl 5.004, this +reset may be disabled by adding the "c" (for "continue") modifier, +i.e. C<m//gc>. This feature, in conjunction with the C<\G> zero-width +assertion, makes it possible to chain matches together. See L<perlop> +and L<perlre>. + +=item C<m//x> ignores whitespace before ?*+{} + +The C<m//x> construct has always been intended to ignore all unescaped +whitespace. However, before Perl 5.004, whitespace had the effect of +escaping repeat modifiers like "*" or "?"; for example, C</a *b/x> was +(mis)interpreted as C</a\*b/x>. This bug has been fixed in 5.004. + +=item nested C<sub{}> closures work now + +Prior to the 5.004 release, nested anonymous functions didn't work +right. They do now. + +=item formats work right on changing lexicals + +Just like anonymous functions that contain lexical variables +that change (like a lexical index variable for a C<foreach> loop), +formats now work properly. For example, this silently failed +before (printed only zeros), but is fine now: + + my $i; + foreach $i ( 1 .. 10 ) { + write; + } + format = + my i is @# + $i + . + +However, it still fails (without a warning) if the foreach is within a +subroutine: + + my $i; + sub foo { + foreach $i ( 1 .. 10 ) { + write; + } + } + foo; + format = + my i is @# + $i + . + +=back + +=head2 New builtin methods + +The C<UNIVERSAL> package automatically contains the following methods that +are inherited by all other classes: + +=over + +=item isa(CLASS) + +C<isa> returns I<true> if its object is blessed into a subclass of C<CLASS> + +C<isa> is also exportable and can be called as a sub with two arguments. This +allows the ability to check what a reference points to. Example: + + use UNIVERSAL qw(isa); + + if(isa($ref, 'ARRAY')) { + ... + } + +=item can(METHOD) + +C<can> checks to see if its object has a method called C<METHOD>, +if it does then a reference to the sub is returned; if it does not then +I<undef> is returned. + +=item VERSION( [NEED] ) + +C<VERSION> returns the version number of the class (package). If the +NEED argument is given then it will check that the current version (as +defined by the $VERSION variable in the given package) not less than +NEED; it will die if this is not the case. This method is normally +called as a class method. This method is called automatically by the +C<VERSION> form of C<use>. + + use A 1.2 qw(some imported subs); + # implies: + A->VERSION(1.2); + +=back + +B<NOTE:> C<can> directly uses Perl's internal code for method lookup, and +C<isa> uses a very similar method and caching strategy. This may cause +strange effects if the Perl code dynamically changes @ISA in any package. + +You may add other methods to the UNIVERSAL class via Perl or XS code. +You do not need to C<use UNIVERSAL> in order to make these methods +available to your program. This is necessary only if you wish to +have C<isa> available as a plain subroutine in the current package. + +=head2 TIEHANDLE now supported + +See L<perltie> for other kinds of tie()s. + +=over + +=item TIEHANDLE classname, LIST + +This is the constructor for the class. That means it is expected to +return an object of some sort. The reference can be used to +hold some internal information. + + sub TIEHANDLE { + print "<shout>\n"; + my $i; + return bless \$i, shift; + } + +=item PRINT this, LIST + +This method will be triggered every time the tied handle is printed to. +Beyond its self reference it also expects the list that was passed to +the print function. + + sub PRINT { + $r = shift; + $$r++; + return print join( $, => map {uc} @_), $\; + } + +=item PRINTF this, LIST + +This method will be triggered every time the tied handle is printed to +with the C<printf()> function. +Beyond its self reference it also expects the format and list that was +passed to the printf function. + + sub PRINTF { + shift; + my $fmt = shift; + print sprintf($fmt, @_)."\n"; + } + +=item READ this LIST + +This method will be called when the handle is read from via the C<read> +or C<sysread> functions. + + sub READ { + $r = shift; + my($buf,$len,$offset) = @_; + print "READ called, \$buf=$buf, \$len=$len, \$offset=$offset"; + } + +=item READLINE this + +This method will be called when the handle is read from. The method +should return undef when there is no more data. + + sub READLINE { + $r = shift; + return "PRINT called $$r times\n" + } + +=item GETC this + +This method will be called when the C<getc> function is called. + + sub GETC { print "Don't GETC, Get Perl"; return "a"; } + +=item DESTROY this + +As with the other types of ties, this method will be called when the +tied handle is about to be destroyed. This is useful for debugging and +possibly for cleaning up. + + sub DESTROY { + print "</shout>\n"; + } + +=back + +=head2 Malloc enhancements + +If perl is compiled with the malloc included with the perl distribution +(that is, if C<perl -V:d_mymalloc> is 'define') then you can print +memory statistics at runtime by running Perl thusly: + + env PERL_DEBUG_MSTATS=2 perl your_script_here + +The value of 2 means to print statistics after compilation and on +exit; with a value of 1, the statistics are printed only on exit. +(If you want the statistics at an arbitrary time, you'll need to +install the optional module Devel::Peek.) + +Three new compilation flags are recognized by malloc.c. (They have no +effect if perl is compiled with system malloc().) + +=over + +=item -DPERL_EMERGENCY_SBRK + +If this macro is defined, running out of memory need not be a fatal +error: a memory pool can allocated by assigning to the special +variable C<$^M>. See L<"$^M">. + +=item -DPACK_MALLOC + +Perl memory allocation is by bucket with sizes close to powers of two. +Because of these malloc overhead may be big, especially for data of +size exactly a power of two. If C<PACK_MALLOC> is defined, perl uses +a slightly different algorithm for small allocations (up to 64 bytes +long), which makes it possible to have overhead down to 1 byte for +allocations which are powers of two (and appear quite often). + +Expected memory savings (with 8-byte alignment in C<alignbytes>) is +about 20% for typical Perl usage. Expected slowdown due to additional +malloc overhead is in fractions of a percent (hard to measure, because +of the effect of saved memory on speed). + +=item -DTWO_POT_OPTIMIZE + +Similarly to C<PACK_MALLOC>, this macro improves allocations of data +with size close to a power of two; but this works for big allocations +(starting with 16K by default). Such allocations are typical for big +hashes and special-purpose scripts, especially image processing. + +On recent systems, the fact that perl requires 2M from system for 1M +allocation will not affect speed of execution, since the tail of such +a chunk is not going to be touched (and thus will not require real +memory). However, it may result in a premature out-of-memory error. +So if you will be manipulating very large blocks with sizes close to +powers of two, it would be wise to define this macro. + +Expected saving of memory is 0-100% (100% in applications which +require most memory in such 2**n chunks); expected slowdown is +negligible. + +=back + +=head2 Miscellaneous efficiency enhancements + +Functions that have an empty prototype and that do nothing but return +a fixed value are now inlined (e.g. C<sub PI () { 3.14159 }>). + +Each unique hash key is only allocated once, no matter how many hashes +have an entry with that key. So even if you have 100 copies of the +same hash, the hash keys never have to be reallocated. + +=head1 Support for More Operating Systems + +Support for the following operating systems is new in Perl 5.004. + +=head2 Win32 + +Perl 5.004 now includes support for building a "native" perl under +Windows NT, using the Microsoft Visual C++ compiler (versions 2.0 +and above) or the Borland C++ compiler (versions 5.02 and above). +The resulting perl can be used under Windows 95 (if it +is installed in the same directory locations as it got installed +in Windows NT). This port includes support for perl extension +building tools like L<MakeMaker> and L<h2xs>, so that many extensions +available on the Comprehensive Perl Archive Network (CPAN) can now be +readily built under Windows NT. See http://www.perl.com/ for more +information on CPAN, and L<README.win32> for more details on how to +get started with building this port. + +There is also support for building perl under the Cygwin32 environment. +Cygwin32 is a set of GNU tools that make it possible to compile and run +many UNIX programs under Windows NT by providing a mostly UNIX-like +interface for compilation and execution. See L<README.cygwin32> for +more details on this port, and how to obtain the Cygwin32 toolkit. + +=head2 Plan 9 + +See L<README.plan9>. + +=head2 QNX + +See L<README.qnx>. + +=head2 AmigaOS + +See L<README.amigaos>. + +=head1 Pragmata + +Six new pragmatic modules exist: + +=over + +=item use autouse MODULE => qw(sub1 sub2 sub3) + +Defers C<require MODULE> until someone calls one of the specified +subroutines (which must be exported by MODULE). This pragma should be +used with caution, and only when necessary. + +=item use blib + +=item use blib 'dir' + +Looks for MakeMaker-like I<'blib'> directory structure starting in +I<dir> (or current directory) and working back up to five levels of +parent directories. + +Intended for use on command line with B<-M> option as a way of testing +arbitrary scripts against an uninstalled version of a package. + +=item use constant NAME => VALUE + +Provides a convenient interface for creating compile-time constants, +See L<perlsub/"Constant Functions">. + +=item use locale + +Tells the compiler to enable (or disable) the use of POSIX locales for +builtin operations. + +When C<use locale> is in effect, the current LC_CTYPE locale is used +for regular expressions and case mapping; LC_COLLATE for string +ordering; and LC_NUMERIC for numeric formating in printf and sprintf +(but B<not> in print). LC_NUMERIC is always used in write, since +lexical scoping of formats is problematic at best. + +Each C<use locale> or C<no locale> affects statements to the end of +the enclosing BLOCK or, if not inside a BLOCK, to the end of the +current file. Locales can be switched and queried with +POSIX::setlocale(). + +See L<perllocale> for more information. + +=item use ops + +Disable unsafe opcodes, or any named opcodes, when compiling Perl code. + +=item use vmsish + +Enable VMS-specific language features. Currently, there are three +VMS-specific features available: 'status', which makes C<$?> and +C<system> return genuine VMS status values instead of emulating POSIX; +'exit', which makes C<exit> take a genuine VMS status value instead of +assuming that C<exit 1> is an error; and 'time', which makes all times +relative to the local time zone, in the VMS tradition. + +=back + +=head1 Modules + +=head2 Required Updates + +Though Perl 5.004 is compatible with almost all modules that work +with Perl 5.003, there are a few exceptions: + + Module Required Version for Perl 5.004 + ------ ------------------------------- + Filter Filter-1.12 + LWP libwww-perl-5.08 + Tk Tk400.202 (-w makes noise) + +Also, the majordomo mailing list program, version 1.94.1, doesn't work +with Perl 5.004 (nor with perl 4), because it executes an invalid +regular expression. This bug is fixed in majordomo version 1.94.2. + +=head2 Installation directories + +The I<installperl> script now places the Perl source files for +extensions in the architecture-specific library directory, which is +where the shared libraries for extensions have always been. This +change is intended to allow administrators to keep the Perl 5.004 +library directory unchanged from a previous version, without running +the risk of binary incompatibility between extensions' Perl source and +shared libraries. + +=head2 Module information summary + +Brand new modules, arranged by topic rather than strictly +alphabetically: + + CGI.pm Web server interface ("Common Gateway Interface") + CGI/Apache.pm Support for Apache's Perl module + CGI/Carp.pm Log server errors with helpful context + CGI/Fast.pm Support for FastCGI (persistent server process) + CGI/Push.pm Support for server push + CGI/Switch.pm Simple interface for multiple server types + + CPAN Interface to Comprehensive Perl Archive Network + CPAN::FirstTime Utility for creating CPAN configuration file + CPAN::Nox Runs CPAN while avoiding compiled extensions + + IO.pm Top-level interface to IO::* classes + IO/File.pm IO::File extension Perl module + IO/Handle.pm IO::Handle extension Perl module + IO/Pipe.pm IO::Pipe extension Perl module + IO/Seekable.pm IO::Seekable extension Perl module + IO/Select.pm IO::Select extension Perl module + IO/Socket.pm IO::Socket extension Perl module + + Opcode.pm Disable named opcodes when compiling Perl code + + ExtUtils/Embed.pm Utilities for embedding Perl in C programs + ExtUtils/testlib.pm Fixes up @INC to use just-built extension + + FindBin.pm Find path of currently executing program + + Class/Struct.pm Declare struct-like datatypes as Perl classes + File/stat.pm By-name interface to Perl's builtin stat + Net/hostent.pm By-name interface to Perl's builtin gethost* + Net/netent.pm By-name interface to Perl's builtin getnet* + Net/protoent.pm By-name interface to Perl's builtin getproto* + Net/servent.pm By-name interface to Perl's builtin getserv* + Time/gmtime.pm By-name interface to Perl's builtin gmtime + Time/localtime.pm By-name interface to Perl's builtin localtime + Time/tm.pm Internal object for Time::{gm,local}time + User/grent.pm By-name interface to Perl's builtin getgr* + User/pwent.pm By-name interface to Perl's builtin getpw* + + Tie/RefHash.pm Base class for tied hashes with references as keys + + UNIVERSAL.pm Base class for *ALL* classes + +=head2 Fcntl + +New constants in the existing Fcntl modules are now supported, +provided that your operating system happens to support them: + + F_GETOWN F_SETOWN + O_ASYNC O_DEFER O_DSYNC O_FSYNC O_SYNC + O_EXLOCK O_SHLOCK + +These constants are intended for use with the Perl operators sysopen() +and fcntl() and the basic database modules like SDBM_File. For the +exact meaning of these and other Fcntl constants please refer to your +operating system's documentation for fcntl() and open(). + +In addition, the Fcntl module now provides these constants for use +with the Perl operator flock(): + + LOCK_SH LOCK_EX LOCK_NB LOCK_UN + +These constants are defined in all environments (because where there is +no flock() system call, Perl emulates it). However, for historical +reasons, these constants are not exported unless they are explicitly +requested with the ":flock" tag (e.g. C<use Fcntl ':flock'>). + +=head2 IO + +The IO module provides a simple mechanism to load all of the IO modules at one +go. Currently this includes: + + IO::Handle + IO::Seekable + IO::File + IO::Pipe + IO::Socket + +For more information on any of these modules, please see its +respective documentation. + +=head2 Math::Complex + +The Math::Complex module has been totally rewritten, and now supports +more operations. These are overloaded: + + + - * / ** <=> neg ~ abs sqrt exp log sin cos atan2 "" (stringify) + +And these functions are now exported: + + pi i Re Im arg + log10 logn ln cbrt root + tan + csc sec cot + asin acos atan + acsc asec acot + sinh cosh tanh + csch sech coth + asinh acosh atanh + acsch asech acoth + cplx cplxe + +=head2 Math::Trig + +This new module provides a simpler interface to parts of Math::Complex for +those who need trigonometric functions only for real numbers. + +=head2 DB_File + +There have been quite a few changes made to DB_File. Here are a few of +the highlights: + +=over + +=item * + +Fixed a handful of bugs. + +=item * + +By public demand, added support for the standard hash function exists(). + +=item * + +Made it compatible with Berkeley DB 1.86. + +=item * + +Made negative subscripts work with RECNO interface. + +=item * + +Changed the default flags from O_RDWR to O_CREAT|O_RDWR and the default +mode from 0640 to 0666. + +=item * + +Made DB_File automatically import the open() constants (O_RDWR, +O_CREAT etc.) from Fcntl, if available. + +=item * + +Updated documentation. + +=back + +Refer to the HISTORY section in DB_File.pm for a complete list of +changes. Everything after DB_File 1.01 has been added since 5.003. + +=head2 Net::Ping + +Major rewrite - support added for both udp echo and real icmp pings. + +=head2 Object-oriented overrides for builtin operators + +Many of the Perl builtins returning lists now have +object-oriented overrides. These are: + + File::stat + Net::hostent + Net::netent + Net::protoent + Net::servent + Time::gmtime + Time::localtime + User::grent + User::pwent + +For example, you can now say + + use File::stat; + use User::pwent; + $his = (stat($filename)->st_uid == pwent($whoever)->pw_uid); + +=head1 Utility Changes + +=head2 pod2html + +=over + +=item Sends converted HTML to standard output + +The I<pod2html> utility included with Perl 5.004 is entirely new. +By default, it sends the converted HTML to its standard output, +instead of writing it to a file like Perl 5.003's I<pod2html> did. +Use the B<--outfile=FILENAME> option to write to a file. + +=back + +=head2 xsubpp + +=over + +=item C<void> XSUBs now default to returning nothing + +Due to a documentation/implementation bug in previous versions of +Perl, XSUBs with a return type of C<void> have actually been +returning one value. Usually that value was the GV for the XSUB, +but sometimes it was some already freed or reused value, which would +sometimes lead to program failure. + +In Perl 5.004, if an XSUB is declared as returning C<void>, it +actually returns no value, i.e. an empty list (though there is a +backward-compatibility exception; see below). If your XSUB really +does return an SV, you should give it a return type of C<SV *>. + +For backward compatibility, I<xsubpp> tries to guess whether a +C<void> XSUB is really C<void> or if it wants to return an C<SV *>. +It does so by examining the text of the XSUB: if I<xsubpp> finds +what looks like an assignment to C<ST(0)>, it assumes that the +XSUB's return type is really C<SV *>. + +=back + +=head1 C Language API Changes + +=over + +=item C<gv_fetchmethod> and C<perl_call_sv> + +The C<gv_fetchmethod> function finds a method for an object, just like +in Perl 5.003. The GV it returns may be a method cache entry. +However, in Perl 5.004, method cache entries are not visible to users; +therefore, they can no longer be passed directly to C<perl_call_sv>. +Instead, you should use the C<GvCV> macro on the GV to extract its CV, +and pass the CV to C<perl_call_sv>. + +The most likely symptom of passing the result of C<gv_fetchmethod> to +C<perl_call_sv> is Perl's producing an "Undefined subroutine called" +error on the I<second> call to a given method (since there is no cache +on the first call). + +=item C<perl_eval_pv> + +A new function handy for eval'ing strings of Perl code inside C code. +This function returns the value from the eval statement, which can +be used instead of fetching globals from the symbol table. See +L<perlguts>, L<perlembed> and L<perlcall> for details and examples. + +=item Extended API for manipulating hashes + +Internal handling of hash keys has changed. The old hashtable API is +still fully supported, and will likely remain so. The additions to the +API allow passing keys as C<SV*>s, so that C<tied> hashes can be given +real scalars as keys rather than plain strings (nontied hashes still +can only use strings as keys). New extensions must use the new hash +access functions and macros if they wish to use C<SV*> keys. These +additions also make it feasible to manipulate C<HE*>s (hash entries), +which can be more efficient. See L<perlguts> for details. + +=back + +=head1 Documentation Changes + +Many of the base and library pods were updated. These +new pods are included in section 1: + +=over + +=item L<perldelta> + +This document. + +=item L<perlfaq> + +Frequently asked questions. + +=item L<perllocale> + +Locale support (internationalization and localization). + +=item L<perltoot> + +Tutorial on Perl OO programming. + +=item L<perlapio> + +Perl internal IO abstraction interface. + +=item L<perlmodlib> + +Perl module library and recommended practice for module creation. +Extracted from L<perlmod> (which is much smaller as a result). + +=item L<perldebug> + +Although not new, this has been massively updated. + +=item L<perlsec> + +Although not new, this has been massively updated. + +=back + +=head1 New Diagnostics + +Several new conditions will trigger warnings that were +silent before. Some only affect certain platforms. +The following new warnings and errors outline these. +These messages are classified as follows (listed in +increasing order of desperation): + + (W) A warning (optional). + (D) A deprecation (optional). + (S) A severe warning (mandatory). + (F) A fatal error (trappable). + (P) An internal error you should never see (trappable). + (X) A very fatal error (nontrappable). + (A) An alien error message (not generated by Perl). + +=over + +=item "my" variable %s masks earlier declaration in same scope + +(W) A lexical variable has been redeclared in the same scope, effectively +eliminating all access to the previous instance. This is almost always +a typographical error. Note that the earlier variable will still exist +until the end of the scope or until all closure referents to it are +destroyed. + +=item %s argument is not a HASH element or slice + +(F) The argument to delete() must be either a hash element, such as + + $foo{$bar} + $ref->[12]->{"susie"} + +or a hash slice, such as + + @foo{$bar, $baz, $xyzzy} + @{$ref->[12]}{"susie", "queue"} + +=item Allocation too large: %lx + +(X) You can't allocate more than 64K on an MS-DOS machine. + +=item Allocation too large + +(F) You can't allocate more than 2^31+"small amount" bytes. + +=item Applying %s to %s will act on scalar(%s) + +(W) The pattern match (//), substitution (s///), and transliteration (tr///) +operators work on scalar values. If you apply one of them to an array +or a hash, it will convert the array or hash to a scalar value -- the +length of an array, or the population info of a hash -- and then work on +that scalar value. This is probably not what you meant to do. See +L<perlfunc/grep> and L<perlfunc/map> for alternatives. + +=item Attempt to free nonexistent shared string + +(P) Perl maintains a reference counted internal table of strings to +optimize the storage and access of hash keys and other strings. This +indicates someone tried to decrement the reference count of a string +that can no longer be found in the table. + +=item Attempt to use reference as lvalue in substr + +(W) You supplied a reference as the first argument to substr() used +as an lvalue, which is pretty strange. Perhaps you forgot to +dereference it first. See L<perlfunc/substr>. + +=item Bareword "%s" refers to nonexistent package + +(W) You used a qualified bareword of the form C<Foo::>, but +the compiler saw no other uses of that namespace before that point. +Perhaps you need to predeclare a package? + +=item Can't redefine active sort subroutine %s + +(F) Perl optimizes the internal handling of sort subroutines and keeps +pointers into them. You tried to redefine one such sort subroutine when it +was currently active, which is not allowed. If you really want to do +this, you should write C<sort { &func } @x> instead of C<sort func @x>. + +=item Can't use bareword ("%s") as %s ref while "strict refs" in use + +(F) Only hard references are allowed by "strict refs". Symbolic references +are disallowed. See L<perlref>. + +=item Cannot resolve method `%s' overloading `%s' in package `%s' + +(P) Internal error trying to resolve overloading specified by a method +name (as opposed to a subroutine reference). + +=item Constant subroutine %s redefined + +(S) You redefined a subroutine which had previously been eligible for +inlining. See L<perlsub/"Constant Functions"> for commentary and +workarounds. + +=item Constant subroutine %s undefined + +(S) You undefined a subroutine which had previously been eligible for +inlining. See L<perlsub/"Constant Functions"> for commentary and +workarounds. + +=item Copy method did not return a reference + +(F) The method which overloads "=" is buggy. See L<overload/Copy Constructor>. + +=item Died + +(F) You passed die() an empty string (the equivalent of C<die "">) or +you called it with no args and both C<$@> and C<$_> were empty. + +=item Exiting pseudo-block via %s + +(W) You are exiting a rather special block construct (like a sort block or +subroutine) by unconventional means, such as a goto, or a loop control +statement. See L<perlfunc/sort>. + +=item Identifier too long + +(F) Perl limits identifiers (names for variables, functions, etc.) to +252 characters for simple names, somewhat more for compound names (like +C<$A::B>). You've exceeded Perl's limits. Future versions of Perl are +likely to eliminate these arbitrary limitations. + +=item Illegal character %s (carriage return) + +(F) A carriage return character was found in the input. This is an +error, and not a warning, because carriage return characters can break +multi-line strings, including here documents (e.g., C<print E<lt>E<lt>EOF;>). + +=item Illegal switch in PERL5OPT: %s + +(X) The PERL5OPT environment variable may only be used to set the +following switches: B<-[DIMUdmw]>. + +=item Integer overflow in hex number + +(S) The literal hex number you have specified is too big for your +architecture. On a 32-bit architecture the largest hex literal is +0xFFFFFFFF. + +=item Integer overflow in octal number + +(S) The literal octal number you have specified is too big for your +architecture. On a 32-bit architecture the largest octal literal is +037777777777. + +=item internal error: glob failed + +(P) Something went wrong with the external program(s) used for C<glob> +and C<E<lt>*.cE<gt>>. This may mean that your csh (C shell) is +broken. If so, you should change all of the csh-related variables in +config.sh: If you have tcsh, make the variables refer to it as if it +were csh (e.g. C<full_csh='/usr/bin/tcsh'>); otherwise, make them all +empty (except that C<d_csh> should be C<'undef'>) so that Perl will +think csh is missing. In either case, after editing config.sh, run +C<./Configure -S> and rebuild Perl. + +=item Invalid conversion in %s: "%s" + +(W) Perl does not understand the given format conversion. +See L<perlfunc/sprintf>. + +=item Invalid type in pack: '%s' + +(F) The given character is not a valid pack type. See L<perlfunc/pack>. + +=item Invalid type in unpack: '%s' + +(F) The given character is not a valid unpack type. See L<perlfunc/unpack>. + +=item Name "%s::%s" used only once: possible typo + +(W) Typographical errors often show up as unique variable names. +If you had a good reason for having a unique name, then just mention +it again somehow to suppress the message (the C<use vars> pragma is +provided for just this purpose). + +=item Null picture in formline + +(F) The first argument to formline must be a valid format picture +specification. It was found to be empty, which probably means you +supplied it an uninitialized value. See L<perlform>. + +=item Offset outside string + +(F) You tried to do a read/write/send/recv operation with an offset +pointing outside the buffer. This is difficult to imagine. +The sole exception to this is that C<sysread()>ing past the buffer +will extend the buffer and zero pad the new area. + +=item Out of memory! + +(X|F) The malloc() function returned 0, indicating there was insufficient +remaining memory (or virtual memory) to satisfy the request. + +The request was judged to be small, so the possibility to trap it +depends on the way Perl was compiled. By default it is not trappable. +However, if compiled for this, Perl may use the contents of C<$^M> as +an emergency pool after die()ing with this message. In this case the +error is trappable I<once>. + +=item Out of memory during request for %s + +(F) The malloc() function returned 0, indicating there was insufficient +remaining memory (or virtual memory) to satisfy the request. However, +the request was judged large enough (compile-time default is 64K), so +a possibility to shut down by trapping this error is granted. + +=item panic: frexp + +(P) The library function frexp() failed, making printf("%f") impossible. + +=item Possible attempt to put comments in qw() list + +(W) qw() lists contain items separated by whitespace; as with literal +strings, comment characters are not ignored, but are instead treated +as literal data. (You may have used different delimiters than the +exclamation marks parentheses shown here; braces are also frequently +used.) + +You probably wrote something like this: + + @list = qw( + a # a comment + b # another comment + ); + +when you should have written this: + + @list = qw( + a + b + ); + +If you really want comments, build your list the +old-fashioned way, with quotes and commas: + + @list = ( + 'a', # a comment + 'b', # another comment + ); + +=item Possible attempt to separate words with commas + +(W) qw() lists contain items separated by whitespace; therefore commas +aren't needed to separate the items. (You may have used different +delimiters than the parentheses shown here; braces are also frequently +used.) + +You probably wrote something like this: + + qw! a, b, c !; + +which puts literal commas into some of the list items. Write it without +commas if you don't want them to appear in your data: + + qw! a b c !; + +=item Scalar value @%s{%s} better written as $%s{%s} + +(W) You've used a hash slice (indicated by @) to select a single element of +a hash. Generally it's better to ask for a scalar value (indicated by $). +The difference is that C<$foo{&bar}> always behaves like a scalar, both when +assigning to it and when evaluating its argument, while C<@foo{&bar}> behaves +like a list when you assign to it, and provides a list context to its +subscript, which can do weird things if you're expecting only one subscript. + +=item Stub found while resolving method `%s' overloading `%s' in package `%s' + +(P) Overloading resolution over @ISA tree may be broken by importing stubs. +Stubs should never be implicitely created, but explicit calls to C<can> +may break this. + +=item Too late for "B<-T>" option + +(X) The #! line (or local equivalent) in a Perl script contains the +B<-T> option, but Perl was not invoked with B<-T> in its argument +list. This is an error because, by the time Perl discovers a B<-T> in +a script, it's too late to properly taint everything from the +environment. So Perl gives up. + +=item untie attempted while %d inner references still exist + +(W) A copy of the object returned from C<tie> (or C<tied>) was still +valid when C<untie> was called. + +=item Unrecognized character %s + +(F) The Perl parser has no idea what to do with the specified character +in your Perl script (or eval). Perhaps you tried to run a compressed +script, a binary program, or a directory as a Perl program. + +=item Unsupported function fork + +(F) Your version of executable does not support forking. + +Note that under some systems, like OS/2, there may be different flavors of +Perl executables, some of which may support fork, some not. Try changing +the name you call Perl by to C<perl_>, C<perl__>, and so on. + +=item Use of "$$<digit>" to mean "${$}<digit>" is deprecated + +(D) Perl versions before 5.004 misinterpreted any type marker followed +by "$" and a digit. For example, "$$0" was incorrectly taken to mean +"${$}0" instead of "${$0}". This bug is (mostly) fixed in Perl 5.004. + +However, the developers of Perl 5.004 could not fix this bug completely, +because at least two widely-used modules depend on the old meaning of +"$$0" in a string. So Perl 5.004 still interprets "$$<digit>" in the +old (broken) way inside strings; but it generates this message as a +warning. And in Perl 5.005, this special treatment will cease. + +=item Value of %s can be "0"; test with defined() + +(W) In a conditional expression, you used <HANDLE>, <*> (glob), C<each()>, +or C<readdir()> as a boolean value. Each of these constructs can return a +value of "0"; that would make the conditional expression false, which is +probably not what you intended. When using these constructs in conditional +expressions, test their values with the C<defined> operator. + +=item Variable "%s" may be unavailable + +(W) An inner (nested) I<anonymous> subroutine is inside a I<named> +subroutine, and outside that is another subroutine; and the anonymous +(innermost) subroutine is referencing a lexical variable defined in +the outermost subroutine. For example: + + sub outermost { my $a; sub middle { sub { $a } } } + +If the anonymous subroutine is called or referenced (directly or +indirectly) from the outermost subroutine, it will share the variable +as you would expect. But if the anonymous subroutine is called or +referenced when the outermost subroutine is not active, it will see +the value of the shared variable as it was before and during the +*first* call to the outermost subroutine, which is probably not what +you want. + +In these circumstances, it is usually best to make the middle +subroutine anonymous, using the C<sub {}> syntax. Perl has specific +support for shared variables in nested anonymous subroutines; a named +subroutine in between interferes with this feature. + +=item Variable "%s" will not stay shared + +(W) An inner (nested) I<named> subroutine is referencing a lexical +variable defined in an outer subroutine. + +When the inner subroutine is called, it will probably see the value of +the outer subroutine's variable as it was before and during the +*first* call to the outer subroutine; in this case, after the first +call to the outer subroutine is complete, the inner and outer +subroutines will no longer share a common value for the variable. In +other words, the variable will no longer be shared. + +Furthermore, if the outer subroutine is anonymous and references a +lexical variable outside itself, then the outer and inner subroutines +will I<never> share the given variable. + +This problem can usually be solved by making the inner subroutine +anonymous, using the C<sub {}> syntax. When inner anonymous subs that +reference variables in outer subroutines are called or referenced, +they are automatically rebound to the current values of such +variables. + +=item Warning: something's wrong + +(W) You passed warn() an empty string (the equivalent of C<warn "">) or +you called it with no args and C<$_> was empty. + +=item Ill-formed logical name |%s| in prime_env_iter + +(W) A warning peculiar to VMS. A logical name was encountered when preparing +to iterate over %ENV which violates the syntactic rules governing logical +names. Since it cannot be translated normally, it is skipped, and will not +appear in %ENV. This may be a benign occurrence, as some software packages +might directly modify logical name tables and introduce nonstandard names, +or it may indicate that a logical name table has been corrupted. + +=item Got an error from DosAllocMem + +(P) An error peculiar to OS/2. Most probably you're using an obsolete +version of Perl, and this should not happen anyway. + +=item Malformed PERLLIB_PREFIX + +(F) An error peculiar to OS/2. PERLLIB_PREFIX should be of the form + + prefix1;prefix2 + +or + + prefix1 prefix2 + +with nonempty prefix1 and prefix2. If C<prefix1> is indeed a prefix +of a builtin library search path, prefix2 is substituted. The error +may appear if components are not found, or are too long. See +"PERLLIB_PREFIX" in F<README.os2>. + +=item PERL_SH_DIR too long + +(F) An error peculiar to OS/2. PERL_SH_DIR is the directory to find the +C<sh>-shell in. See "PERL_SH_DIR" in F<README.os2>. + +=item Process terminated by SIG%s + +(W) This is a standard message issued by OS/2 applications, while *nix +applications die in silence. It is considered a feature of the OS/2 +port. One can easily disable this by appropriate sighandlers, see +L<perlipc/"Signals">. See also "Process terminated by SIGTERM/SIGINT" +in F<README.os2>. + +=back + +=head1 BUGS + +If you find what you think is a bug, you might check the headers of +recently posted articles in the comp.lang.perl.misc newsgroup. +There may also be information at http://www.perl.com/perl/, the Perl +Home Page. + +If you believe you have an unreported bug, please run the B<perlbug> +program included with your release. Make sure you trim your bug down +to a tiny but sufficient test case. Your bug report, along with the +output of C<perl -V>, will be sent off to <F<perlbug@perl.com>> to be +analysed by the Perl porting team. + +=head1 SEE ALSO + +The F<Changes> file for exhaustive details on what changed. + +The F<INSTALL> file for how to build Perl. This file has been +significantly updated for 5.004, so even veteran users should +look through it. + +The F<README> file for general stuff. + +The F<Copying> file for copyright information. + +=head1 HISTORY + +Constructed by Tom Christiansen, grabbing material with permission +from innumerable contributors, with kibitzing by more than a few Perl +porters. + +Last update: Wed May 14 11:14:09 EDT 1997 |