\input texinfo @c -*-texinfo-*- @comment %**start of header @setfilename libunistring.info @documentencoding UTF-8 @settitle GNU libunistring @finalout @c Indices: @c am = autoconf macro @amindex @c cp = concept @cindex @c fn = function @findex @c tp = type @tindex @c Unused predefined indices: @c ky = keystroke @kindex @c pg = program @pindex @c vr = variable @vindex @defcodeindex am @syncodeindex am cp @syncodeindex fn cp @syncodeindex tp cp @ifclear texi2html @firstparagraphindent insert @end ifclear @c texi2html-1.76 does not support @arrow{}. @ifset texi2html @macro arrow{} → @end macro @end ifset @comment %**end of header @include version.texi @c Location of the POSIX specification on the web. @set POSIXURL http://www.opengroup.org/onlinepubs/9699919799 @c Macro for referencing a POSIX function. @c We don't write it as func(), see section "GNU Manuals" of the @c GNU coding standards. @ifinfo @macro posixfunc{func} @code{\func\} @end macro @end ifinfo @ifnotinfo @macro posixfunc{func} @uref{@value{POSIXURL}/functions/\func\.html,,@code{\func\}} @end macro @end ifnotinfo @c Macro for referencing a normal function. @c We don't write it as func(), see section "GNU Manuals" of the @c GNU coding standards. @macro func{func} @code{\func\} @end macro @c Macro for an advisory ragged line break in TeX mode. @c Needed because there are long unbreakable pieces of text (such as URLs or @c formulas), TeX is too shy to move them to a new line. TeX considers only @c two choices: a line break in aligned mode (which it rejects due to aesthetic @c reasons) and writing into the margin. What we want in many cases is a line @c break without filling the first line. Like what @* delivers. But we want it @c only when needed, so that it disappears when unrelated changes in the same @c paragraph cause a line break in a nearby position. And we need it only in @c TeX mode. info and HTML modes are fine. @c This trick is from Karl Berry. @iftex @macro texnl @hfil@penalty9000@hfilneg @end macro @end iftex @ifnottex @macro texnl @end macro @end ifnottex @ifinfo @dircategory Software development @direntry * GNU libunistring: (libunistring). Unicode string library. @end direntry @end ifinfo @ifinfo This manual is for GNU libunistring. @ignore @c This was: @copying but it triggers a makeinfo 4.13 bug Copyright (C) 2001-2010 Free Software Foundation, Inc. This manual is free documentation. It is dually licensed under the GNU FDL and the GNU GPL. This means that you can redistribute this manual under either of these two licenses, at your choice. This manual is covered by the GNU FDL. Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License (FDL), either version 1.2 of the License, or (at your option) any later version published by the Free Software Foundation (FSF); with no Invariant Sections, with no Front-Cover Text, and with no Back-Cover Texts. A copy of the license is included in @ref{GNU FDL}. This manual is covered by the GNU GPL. You can redistribute it and/or modify it under the terms of the GNU General Public License (GPL), either version 3 of the License, or (at your option) any later version published by the Free Software Foundation (FSF). A copy of the license is included in @ref{GNU GPL}. @end ignore @end ifinfo @titlepage @title GNU libunistring, version @value{VERSION} @subtitle updated @value{UPDATED} @subtitle Edition @value{EDITION}, @value{UPDATED} @author Bruno Haible @ifnothtml @page @vskip 0pt plus 1filll @c @insertcopying Copyright (C) 2001-2010 Free Software Foundation, Inc. This manual is free documentation. It is dually licensed under the GNU FDL and the GNU GPL. This means that you can redistribute this manual under either of these two licenses, at your choice. This manual is covered by the GNU FDL. Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License (FDL), either version 1.2 of the License, or (at your option) any later version published by the Free Software Foundation (FSF); with no Invariant Sections, with no Front-Cover Text, and with no Back-Cover Texts. A copy of the license is included in @ref{GNU FDL}. This manual is covered by the GNU GPL. You can redistribute it and/or modify it under the terms of the GNU General Public License (GPL), either version 3 of the License, or (at your option) any later version published by the Free Software Foundation (FSF). A copy of the license is included in @ref{GNU GPL}. @end ifnothtml @end titlepage @c Table of Contents @contents @ifnottex @node Top @top GNU libunistring @end ifnottex @menu * Introduction:: Who may need Unicode strings? * Conventions:: Conventions used in this manual * unitypes.h:: Elementary types * unistr.h:: Elementary Unicode string functions * uniconv.h:: Conversions between Unicode and encodings * unistdio.h:: Output with Unicode strings * uniname.h:: Names of Unicode characters * unictype.h:: Unicode character classification and properties * uniwidth.h:: Display width * unigbrk.h:: Grapheme cluster breaking * uniwbrk.h:: Word breaks in strings * unilbrk.h:: Line breaking * uninorm.h:: Normalization forms * unicase.h:: Case mappings * uniregex.h:: Regular expressions * Using the library:: How to link with the library and use it? * More functionality:: More advanced functionality * Licenses:: Licenses * Index:: General Index @detailmenu --- The Detailed Node Listing --- Introduction * Unicode:: What is Unicode? * Unicode and i18n:: Unicode and internationalization * Locale encodings:: What is a locale encoding? * In-memory representation:: How to represent strings in memory? * char * strings:: What to keep in mind with @code{char *} strings * The wchar_t mess:: Why @code{wchar_t *} strings are useless * Unicode strings:: How are Unicode strings represented? unistr.h * Elementary string checks:: * Elementary string conversions:: * Elementary string functions:: * Elementary string functions with memory allocation:: * Elementary string functions on NUL terminated strings:: unictype.h * General category:: * Canonical combining class:: * Bidi class:: * Decimal digit value:: * Digit value:: * Numeric value:: * Mirrored character:: * Arabic shaping:: * Properties:: * Scripts:: * Blocks:: * ISO C and Java syntax:: * Classifications like in ISO C:: General category * Object oriented API:: * Bit mask API:: Properties * Properties as objects:: * Properties as functions:: unigbrk.h * Grapheme cluster breaks in a string:: * Grapheme cluster break property:: uniwbrk.h * Word breaks in a string:: * Word break property:: uninorm.h * Decomposition of characters:: * Composition of characters:: * Normalization of strings:: * Normalizing comparisons:: * Normalization of streams:: unicase,h * Case mappings of characters:: * Case mappings of strings:: * Case mappings of substrings:: * Case insensitive comparison:: * Case detection:: Using the library * Installation:: * Compiler options:: * Include files:: * Autoconf macro:: * Reporting problems:: Licenses * GNU GPL:: GNU General Public License * GNU LGPL:: GNU Lesser General Public License * GNU FDL:: GNU Free Documentation License @end detailmenu @end menu @node Introduction @chapter Introduction This library provides functions for manipulating Unicode strings and for manipulating C strings according to the Unicode standard. It consists of the following parts: @table @code @item elementary string functions @item conversion from/to legacy encodings @item formatted output to strings @item character names @item character classification and properties @item string width when using nonproportional fonts @item grapheme cluster breaks @item word breaks @item line breaking algorithm @item normalization (composition and decomposition) @item case folding @item regular expressions (not yet implemented) @end table @cindex use cases @cindex value, of libunistring libunistring is for you if your application involves non-trivial text processing, such as upper/lower case conversions, line breaking, operations on words, or more advanced analysis of text. Text provided by the user can, in general, contain characters of all kinds of scripts. The text processing functions provided by this library handle all scripts and all languages. libunistring is for you if your application already uses the ISO C / POSIX @code{}, @code{} functions and the text it operates on is provided by the user and can be in any language. libunistring is also for you if your application uses Unicode strings as internal in-memory representation. @menu * Unicode:: What is Unicode? * Unicode and i18n:: Unicode and internationalization * Locale encodings:: What is a locale encoding? * In-memory representation:: How to represent strings in memory? * char * strings:: What to keep in mind with @code{char *} strings * The wchar_t mess:: Why @code{wchar_t *} strings are useless * Unicode strings:: How are Unicode strings represented? @end menu @node Unicode @section Unicode @cindex Unicode Unicode is a standardized repertoire of characters that contains characters from all scripts of the world, from Latin letters to Chinese ideographs and Babylonian cuneiform glyphs. It also specifies how these characters are to be rendered on a screen or on paper, and how common text processing (word selection, line breaking, uppercasing of page titles etc.) is supposed to behave on Unicode text. Unicode also specifies three ways of storing sequences of Unicode characters in a computer whose basic unit of data is an 8-bit byte: @cindex UTF-8 @cindex UTF-16 @cindex UTF-32 @cindex UCS-4 @table @asis @item UTF-8 Every character is represented as 1 to 4 bytes. @item UTF-16 Every character is represented as 1 to 2 units of 16 bits. @item UTF-32, a.k.a@. UCS-4 Every character is represented as 1 unit of 32 bits. @end table For encoding Unicode text in a file, UTF-8 is usually used. For encoding Unicode strings in memory for a program, either of the three encoding forms can be reasonably used. Unicode is widely used on the web. Prior to the use of Unicode, web pages were in many different encodings (ISO-8859-1 for English, French, Spanish, ISO-8859-2 for Polish, ISO-8859-7 for Greek, KOI8-R for Russian, GB2312 or BIG5 for Chinese, ISO-2022-JP-2 or EUC-JP or Shift_JIS for Japanese, and many many others). It was next to impossible to create a document that contained Chinese and Polish text in the same document. Due to the many encodings for Japanese, even the processing of pure Japanese text was error prone. References: @itemize @bullet @item The Unicode standard:@texnl{} @url{http://www.unicode.org/} @item Definition of UTF-8:@texnl{} @url{http://www.rfc-editor.org/rfc/rfc3629.txt} @item Definition of UTF-16:@texnl{} @url{http://www.rfc-editor.org/rfc/rfc2781.txt} @item Markus Kuhn's UTF-8 and Unicode FAQ:@texnl{} @url{http://www.cl.cam.ac.uk/~mgk25/unicode.html} @end itemize @node Unicode and i18n @section Unicode and Internationalization @cindex internationalization Internationalization is the process of changing the source code of a program so that it can meet the expectations of users in any culture, if culture specific data (translations, images etc.) are provided. Use of Unicode is not strictly required for internationalization, but it makes internationalization much easier, because operations that need to look at specific characters (like hyphenation, spell checking, or the automatic conversion of double-quotes to opening and closing double-quote characters) don't need to consider multiple possible encodings of the text. Use of Unicode also enables multilingualization: the ability of having text in multiple languages present in the same document or even in the same line of text. But use of Unicode is not everything. Internationalization usually consists of three features: @itemize @bullet @item Use of Unicode where needed for text processing. This is what this library is for. @item Use of message catalogs for messages shown to the user, This is what GNU gettext is about. @item Use of locale specific conventions for date and time formats, for numeric formatting, or for sorting of text. This can be done adequately with the POSIX APIs and the implementation of locales in the GNU C library. @end itemize @node Locale encodings @section Locale encodings @cindex locale A locale is a set of cultural conventions. According to POSIX, for a program, at any moment, there is one locale being designated as the ``current locale''. (Actually, POSIX supports also one locale per thread, but this feature is not yet universally implemented and not widely used.) @cindex locale categories The locale is partitioned into several aspects, called the ``categories'' of the locale. The main various aspects are: @itemize @item The character encoding and the character properties. This is the @code{LC_CTYPE} category. @item The sorting rules for text. This is the @code{LC_COLLATE} category. @item The language specific translations of messages. This is the @code{LC_MESSAGES} category. @item The formatting rules for numbers, such as the decimal separator. This is the @code{LC_NUMERIC} category. @item The formatting rules for amounts of money. This is the @code{LC_MONETARY} category. @item The formatting of date and time. This is the @code{LC_TIME} category. @end itemize @cindex locale encoding In particular, the @code{LC_CTYPE} category of the current locale determines the character encoding. This is the encoding of @samp{char *} strings. We also call it the ``locale encoding''. GNU libunistring has a function, @func{locale_charset}, that returns a standardized (platform independent) name for this encoding. All locale encodings used on glibc systems are essentially ASCII compatible: Most graphic ASCII characters have the same representation, as a single byte, in that encoding as in ASCII. Among the possible locale encodings are UTF-8 and GB18030. Both allow to represent any Unicode character as a sequence of bytes. UTF-8 is used in most of the world, whereas GB18030 is used in the People's Republic of China, because it is backward compatible with the GB2312 encoding that was used in this country earlier. The legacy locale encodings, ISO-8859-15 (which supplanted ISO-8859-1 in most of Europe), ISO-8859-2, KOI8-R, EUC-JP, etc., are still in use in many places, though. UTF-16 and UTF-32 are not used as locale encodings, because they are not ASCII compatible. @node In-memory representation @section Choice of in-memory representation of strings There are three ways of representing strings in memory of a running program. @itemize @item As @samp{char *} strings. Such strings are represented in locale encoding. This approach is employed when not much text processing is done by the program. When some Unicode aware processing is to be done, a string is converted to Unicode on the fly and back to locale encoding afterwards. @item As UTF-8 or UTF-16 or UTF-32 strings. This implies that conversion from locale encoding to Unicode is performed on input, and in the opposite direction on output. This approach is employed when the program does a significant amount of text processing, or when the program has multiple threads operating on the same data but in different locales. @item As @samp{wchar_t *}, a.k.a@. ``wide strings''. This approach is misguided, see @ref{The wchar_t mess}. @end itemize @node char * strings @section @samp{char *} strings @cindex C string functions The classical C strings, with its C library support standardized by ISO C and POSIX, can be used in internationalized programs with some precautions. The problem with this API is that many of the C library functions for strings don't work correctly on strings in locale encodings, leading to bugs that only people in some cultures of the world will experience. @cindex locale, multibyte The first problem with the C library API is the support of multibyte locales. According to the locale encoding, in general, every character is represented by one or more bytes (up to 4 bytes in practice --- but use @code{MB_LEN_MAX} instead of the number 4 in the code). When every character is represented by only 1 byte, we speak of an ``unibyte locale'', otherwise of a ``multibyte locale''. It is important to realize that the majority of Unix installations nowadays use UTF-8 or GB18030 as locale encoding; therefore, the majority of users are using multibyte locales. @cindex char, type The important fact to remember is: @cartouche @emph{A @samp{char} is a byte, not a character.} @end cartouche As a consequence: @itemize @item The @code{} API is useless in this context; it does not work in multibyte locales. @item The @posixfunc{strlen} function does not return the number of characters in a string. Nor does it return the number of screen columns occupied by a string after it is output. It merely returns the number of @emph{bytes} occupied by a string. @item Truncating a string, for example, with @posixfunc{strncpy}, can have the effect of truncating it in the middle of a multibyte character. Such a string will, when output, have a garbled character at its end, often represented by a hollow box. @item @posixfunc{strchr} and @posixfunc{strrchr} do not work with multibyte strings if the locale encoding is GB18030 and the character to be searched is a digit. @item @posixfunc{strstr} does not work with multibyte strings if the locale encoding is different from UTF-8. @item @posixfunc{strcspn}, @posixfunc{strpbrk}, @posixfunc{strspn} cannot work correctly in multibyte locales: they assume the second argument is a list of single-byte characters. Even in this simple case, they do not work with multibyte strings if the locale encoding is GB18030 and one of the characters to be searched is a digit. @item @posixfunc{strsep} and @posixfunc{strtok_r} do not work with multibyte strings unless all of the delimiter characters are ASCII characters < 0x30. @item The @posixfunc{strcasecmp}, @posixfunc{strncasecmp}, and @posixfunc{strcasestr} functions do not work with multibyte strings. @end itemize The workarounds can be found in GNU gnulib @url{http://www.gnu.org/software/gnulib/}. @itemize @item gnulib has modules @samp{mbchar}, @samp{mbiter}, @samp{mbuiter} that represent multibyte characters and allow to iterate across a multibyte string with the same ease as through a unibyte string. @item gnulib has functions @func{mbslen} and @func{mbswidth} that can be used instead of @posixfunc{strlen} when the number of characters or the number of screen columns of a string is requested. @item gnulib has functions @func{mbschr} and @func{mbsrrchr} that are like @posixfunc{strchr} and @posixfunc{strrchr}, but work in multibyte locales. @item gnulib has a function @func{mbsstr}, like @posixfunc{strstr}, but works in multibyte locales. @item gnulib has functions @func{mbscspn}, @func{mbspbrk}, @func{mbsspn} that are like @posixfunc{strcspn}, @posixfunc{strpbrk}, @posixfunc{strspn}, but work in multibyte locales. @item gnulib has functions @func{mbssep} and @func{mbstok_r} that are like @posixfunc{strsep} and @posixfunc{strtok_r} but work in multibyte locales. @item gnulib has functions @func{mbscasecmp}, @func{mbsncasecmp}, @func{mbspcasecmp}, and @func{mbscasestr} that are like @posixfunc{strcasecmp}, @posixfunc{strncasecmp}, and @posixfunc{strcasestr}, but work in multibyte locales. Still, the function @code{ulc_casecmp} is preferable to these functions; see below. @end itemize The second problem with the C library API is that it has some assumptions built-in that are not valid in some languages: @itemize @item It assumes that there are only two forms of every character: uppercase and lowercase. This is not true for Croatian, where the character @sc{LETTER DZ WITH CARON} comes in three forms: @sc{LATIN CAPITAL LETTER DZ WITH CARON} (DZ), @sc{LATIN CAPITAL LETTER D WITH SMALL LETTER Z WITH CARON} (Dz), @sc{LATIN SMALL LETTER DZ WITH CARON} (dz). @item It assumes that uppercasing of 1 character leads to 1 character. This is not true for German, where the @sc{LATIN SMALL LETTER SHARP S}, when uppercased, becomes @samp{SS}. @item It assumes that there is 1:1 mapping between uppercase and lowercase forms. This is not true for the Greek sigma: @sc{GREEK CAPITAL LETTER SIGMA} is the uppercase of both @sc{GREEK SMALL LETTER SIGMA} and @sc{GREEK SMALL LETTER FINAL SIGMA}. @item It assumes that the upper/lowercase mappings are position independent. This is not true for the Greek sigma and the Lithuanian i. @end itemize The correct way to deal with this problem is @enumerate @item to provide functions for titlecasing, as well as for upper- and lowercasing, @item to view case transformations as functions that operates on strings, rather than on characters. @end enumerate This is implemented in this library, through the functions declared in @code{}, see @ref{unicase.h}. @node The wchar_t mess @section The @code{wchar_t} mess @cindex wchar_t, type The ISO C and POSIX standard creators made an attempt to fix the first problem mentioned in the previous section. They introduced @itemize @item a type @samp{wchar_t}, designed to encapsulate an entire character, @item a ``wide string'' type @samp{wchar_t *}, and @item functions declared in @code{} that were meant to supplant the ones in @code{}. @end itemize Unfortunately, this API and its implementation has numerous problems: @itemize @item On AIX and Windows platforms, @code{wchar_t} is a 16-bit type. This means that it can never accommodate an entire Unicode character. Either the @code{wchar_t *} strings are limited to characters in UCS-2 (the ``Basic Multilingual Plane'' of Unicode), or --- if @code{wchar_t *} strings are encoded in UTF-16 --- a @code{wchar_t} represents only half of a character in the worst case, making the @code{} functions pointless. @item On Solaris and FreeBSD, the @code{wchar_t} encoding is locale dependent and undocumented. This means, if you want to know any property of a @code{wchar_t} character, other than the properties defined by @code{} --- such as whether it's a dash, currency symbol, paragraph separator, or similar ---, you have to convert it to @code{char *} encoding first, by use of the function @posixfunc{wctomb}. @item When you read a stream of wide characters, through the functions @posixfunc{fgetwc} and @posixfunc{fgetws}, and when the input stream/file is not in the expected encoding, you have no way to determine the invalid byte sequence and do some corrective action. If you use these functions, your program becomes ``garbage in - more garbage out'' or ``garbage in - abort''. @end itemize As a consequence, it is better to use multibyte strings, as explained in the previous section. Such multibyte strings can bypass limitations of the @code{wchar_t} type, if you use functions defined in gnulib and libunistring for text processing. They can also faithfully transport malformed characters that were present in the input, without requiring the program to produce garbage or abort. @node Unicode strings @section Unicode strings libunistring supports Unicode strings in three representations: @cindex UTF-8, strings @cindex UTF-16, strings @cindex UTF-32, strings @itemize @item UTF-8 strings, through the type @samp{uint8_t *}. The units are bytes (@code{uint8_t}). @item UTF-16 strings, through the type @samp{uint16_t *}, The units are 16-bit memory words (@code{uint16_t}). @item UTF-32 strings, through the type @samp{uint32_t *}. The units are 32-bit memory words (@code{uint32_t}). @end itemize As with C strings, there are two variants: @itemize @item Unicode strings with a terminating NUL character are represented as a pointer to the first unit of the string. There is a unit containing a 0 value at the end. It is considered part of the string for all memory allocation purposes, but is not considered part of the string for all other logical purposes. @item Unicode strings where embedded NUL characters are allowed. These are represented by a pointer to the first unit and the number of units (not bytes!) of the string. In this setting, there is no trailing zero-valued unit used as ``end marker''. @end itemize @node Conventions @chapter Conventions This chapter explains conventions valid throughout the libunistring library. @cindex argument conventions Variables of type @code{char *} denote C strings in locale encoding. See @ref{Locale encodings}. Variables of type @code{uint8_t *} denote UTF-8 strings. Their units are bytes. Variables of type @code{uint16_t *} denote UTF-16 strings, without byte order mark. Their units are 2-byte words. Variables of type @code{uint32_t *} denote UTF-32 strings, without byte order mark. Their units are 4-byte words. Argument pairs @code{(@var{s}, @var{n})} denote a string @code{@var{s}[0..@var{n}-1]} with exactly @var{n} units. All functions with prefix @samp{ulc_} operate on C strings in locale encoding. All functions with prefix @samp{u8_} operate on UTF-8 strings. All functions with prefix @samp{u16_} operate on UTF-16 strings. All functions with prefix @samp{u32_} operate on UTF-32 strings. For every function with prefix @samp{u8_}, operating on UTF-8 strings, there is also a corresponding function with prefix @samp{u16_}, operating on UTF-16 strings, and a corresponding function with prefix @samp{u32_}, operating on UTF-32 strings. Their description is analogous; in this documentation we describe only the function that operates on UTF-8 strings, for brevity. A declaration with a variable @var{n} denotes the three concrete declarations with @var{n} = 8, @var{n} = 16, @var{n} = 32. All parameters starting with @samp{str} and the parameters of functions starting with @code{u8_str}/@code{u16_str}/@code{u32_str} denote a NUL terminated string. @cindex return value conventions Error values are always returned through the @code{errno} variable, usually with a return value that indicates the presence of an error (NULL for functions that return an pointer, or -1 for functions that return an @code{int}). Functions returning a string result take a @code{(@var{resultbuf}, @var{lengthp})} argument pair. If @var{resultbuf} is not NULL and the result fits into @code{*@var{lengthp}} units, it is put in @var{resultbuf}, and @var{resultbuf} is returned. Otherwise, a freshly allocated string is returned. In both cases, @code{*@var{lengthp}} is set to the length (number of units) of the returned string. In case of error, NULL is returned and @code{errno} is set. @include unitypes.texi @include unistr.texi @include uniconv.texi @include unistdio.texi @include uniname.texi @include unictype.texi @include uniwidth.texi @include unigbrk.texi @include uniwbrk.texi @include unilbrk.texi @include uninorm.texi @include unicase.texi @include uniregex.texi @node Using the library @chapter Using the library This chapter explains some practical considerations, regarding the installation and compiler options that are needed in order to use this library. @menu * Installation:: * Compiler options:: * Include files:: * Autoconf macro:: * Reporting problems:: @end menu @node Installation @section Installation @cindex dependencies Before you can use the library, it must be installed. First, you have to make sure all dependencies are installed. They are listed in the file @file{DEPENDENCIES}. @cindex installation Then you can proceed to build and install the library, as described in the file @file{INSTALL}. For installation on Windows systems, please refer to the file @file{README.woe32}. @node Compiler options @section Compiler options Let's denote as @code{LIBUNISTRING_PREFIX} the value of the @samp{--prefix} option that you passed to @code{configure} while installing this package. If you didn't pass any @samp{--prefix} option, then the package is installed in @file{/usr/local}. Let's denote as @code{LIBUNISTRING_INCLUDEDIR} the directory where the include files were installed. This is usually the same as @code{$@{LIBUNISTRING_PREFIX@}/include}. Except that if you passed an @samp{--includedir} option to @code{configure}, it is the value of that option. Let's further denote as @code{LIBUNISTRING_LIBDIR} the directory where the library itself was installed. This is the value that you passed with the @samp{--libdir} option to @code{configure}, or otherwise the same as @code{$@{LIBUNISTRING_PREFIX@}/lib}. Recall that when building in 64-bit mode on a 64-bit GNU/Linux system that supports executables in either 64-bit mode or 32-bit mode, you should have used the option @code{--libdir=$@{LIBUNISTRING_PREFIX@}/lib64}. @cindex compiler options So that the compiler finds the include files, you have to pass it the option @code{-I$@{LIBUNISTRING_INCLUDEDIR@}}. So that the compiler finds the library during its linking pass, you have to pass it the options @code{-L$@{LIBUNISTRING_LIBDIR@} -lunistring}. On some systems, in some configurations, you also have to pass options needed for linking with @code{libiconv}. The autoconf macro @code{gl_LIBUNISTRING} (see @ref{Autoconf macro}) deals with this particularity. @node Include files @section Include files Most of the include files have been presented in the introduction, see @ref{Introduction}, and subsequent detailed chapters. Another include file is @code{}. It contains the version number of the libunistring library. @deftypevr Macro int _LIBUNISTRING_VERSION This constant contains the version of libunistring that is being used at compile time. It encodes the major and minor parts of the version number only. These parts are encoded in the form @code{(major<<8) + minor}. @end deftypevr @deftypevr Constant int _libunistring_version This constant contains the version of libunistring that is being used at run time. It encodes the major and minor parts of the version number only. These parts are encoded in the form @code{(major<<8) + minor}. @end deftypevr It is possible that @code{_libunistring_version} is greater than @code{_LIBUNISTRING_VERSION}. This can happen when you use @code{libunistring} as a shared library, and a newer, binary backward-compatible version has been installed after your program that uses @code{libunistring} was installed. @node Autoconf macro @section Autoconf macro @cindex autoconf macro GNU Gnulib provides an autoconf macro that tests for the availability of @code{libunistring}. It is contained in the Gnulib module @samp{libunistring}, see@texnl{} @url{http://www.gnu.org/software/gnulib/MODULES.html#module=libunistring}. @amindex gl_LIBUNISTRING The macro is called @code{gl_LIBUNISTRING}. It searches for an installed libunistring. If found, it sets and AC_SUBSTs @code{HAVE_LIBUNISTRING=yes} and the @code{LIBUNISTRING} and @code{LTLIBUNISTRING} variables and augments the @code{CPPFLAGS} variable, and defines the C macro @code{HAVE_LIBUNISTRING} to 1. Otherwise, it sets and AC_SUBSTs @code{HAVE_LIBUNISTRING=no} and @code{LIBUNISTRING} and @code{LTLIBUNISTRING} to empty. The complexities that @code{gl_LIBUNISTRING} deals with are the following: @itemize @bullet @item On some operating systems, in some configurations, libunistring depends on @code{libiconv}, and the options for linking with libiconv must be mentioned explicitly on the link command line. @item GNU @code{libunistring}, if installed, is not necessarily already in the search path (@code{CPPFLAGS} for the include file search path, @code{LDFLAGS} for the library search path). @item GNU @code{libunistring}, if installed, is not necessarily already in the run time library search path. To avoid the need for setting an environment variable like @code{LD_LIBRARY_PATH}, the macro adds the appropriate run time search path options to the @code{LIBUNISTRING} variable. This works on most systems. @end itemize @node Reporting problems @section Reporting problems @cindex bug reports @cindex bug tracker @cindex mailing list If you encounter any problem, please don't hesitate to send a detailed bug report to the @code{bug-libunistring@@gnu.org} mailing list. You can alternatively also use the bug tracker at the project page @url{https://savannah.gnu.org/projects/libunistring}. Please always include the version number of this library, and a short description of your operating system and compilation environment with corresponding version numbers. For problems that appear while building and installing @code{libunistring}, for which you don't find the remedy in the @file{INSTALL} file, please include a description of the options that you passed to the @samp{configure} script. @node More functionality @chapter More advanced functionality @cindex bidirectional reordering For bidirectional reordering of strings, we recommend the GNU FriBidi library: @url{http://www.fribidi.org/}. @cindex rendering For the rendering of Unicode strings outside of the context of a given toolkit (KDE/Qt or GNOME/Gtk), we recommend the Pango library: @url{http://www.pango.org/}. @node Licenses @appendix Licenses @cindex Licenses The files of this package are covered by the licenses indicated in each particular file or directory. Here is a summary: @itemize @bullet @item The @code{libunistring} library is covered by the GNU Lesser General Public License (LGPL). A copy of the license is included in @ref{GNU LGPL}. @item This manual is free documentation. It is dually licensed under the GNU FDL and the GNU GPL. This means that you can redistribute this manual under either of these two licenses, at your choice. @* This manual is covered by the GNU FDL. Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License (FDL), either version 1.2 of the License, or (at your option) any later version published by the Free Software Foundation (FSF); with no Invariant Sections, with no Front-Cover Text, and with no Back-Cover Texts. A copy of the license is included in @ref{GNU FDL}. @* This manual is covered by the GNU GPL. You can redistribute it and/or modify it under the terms of the GNU General Public License (GPL), either version 3 of the License, or (at your option) any later version published by the Free Software Foundation (FSF). A copy of the license is included in @ref{GNU GPL}. @end itemize @menu * GNU GPL:: GNU General Public License * GNU LGPL:: GNU Lesser General Public License * GNU FDL:: GNU Free Documentation License @end menu @page @node GNU GPL @appendixsec GNU GENERAL PUBLIC LICENSE @cindex GPL, GNU General Public License @cindex License, GNU GPL @include gpl.texi @page @node GNU LGPL @appendixsec GNU LESSER GENERAL PUBLIC LICENSE @cindex LGPL, GNU Lesser General Public License @cindex License, GNU LGPL @include lgpl.texi @page @node GNU FDL @appendixsec GNU Free Documentation License @cindex FDL, GNU Free Documentation License @cindex License, GNU FDL @include fdl.texi @node Index @unnumbered Index @printindex cp @bye @c Local Variables: @c indent-tabs-mode: nil @c whitespace-check-buffer-indent: nil @c End: