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diff --git a/srclib/pcre/doc/html/pcreapi.html b/srclib/pcre/doc/html/pcreapi.html deleted file mode 100644 index 72639f4cc3..0000000000 --- a/srclib/pcre/doc/html/pcreapi.html +++ /dev/null @@ -1,1287 +0,0 @@ -<html> -<head> -<title>pcreapi specification</title> -</head> -<body bgcolor="#FFFFFF" text="#00005A" link="#0066FF" alink="#3399FF" vlink="#2222BB"> -<h1>pcreapi man page</h1> -<p> -Return to the <a href="index.html">PCRE index page</a>. -</p> -<p> -This page is part of the PCRE HTML documentation. It was 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. -<br> -<ul> -<li><a name="TOC1" href="#SEC1">PCRE NATIVE API</a> -<li><a name="TOC2" href="#SEC2">PCRE API OVERVIEW</a> -<li><a name="TOC3" href="#SEC3">MULTITHREADING</a> -<li><a name="TOC4" href="#SEC4">SAVING PRECOMPILED PATTERNS FOR LATER USE</a> -<li><a name="TOC5" href="#SEC5">CHECKING BUILD-TIME OPTIONS</a> -<li><a name="TOC6" href="#SEC6">COMPILING A PATTERN</a> -<li><a name="TOC7" href="#SEC7">STUDYING A PATTERN</a> -<li><a name="TOC8" href="#SEC8">LOCALE SUPPORT</a> -<li><a name="TOC9" href="#SEC9">INFORMATION ABOUT A PATTERN</a> -<li><a name="TOC10" href="#SEC10">OBSOLETE INFO FUNCTION</a> -<li><a name="TOC11" href="#SEC11">MATCHING A PATTERN</a> -<li><a name="TOC12" href="#SEC12">EXTRACTING CAPTURED SUBSTRINGS BY NUMBER</a> -<li><a name="TOC13" href="#SEC13">EXTRACTING CAPTURED SUBSTRINGS BY NAME</a> -</ul> -<br><a name="SEC1" href="#TOC1">PCRE NATIVE API</a><br> -<P> -<b>#include <pcre.h></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_named_substring(const pcre *<i>code</i>,</b> -<b>const char *<i>subject</i>, int *<i>ovector</i>,</b> -<b>int <i>stringcount</i>, const char *<i>stringname</i>,</b> -<b>char *<i>buffer</i>, int <i>buffersize</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_named_substring(const pcre *<i>code</i>,</b> -<b>const char *<i>subject</i>, int *<i>ovector</i>,</b> -<b>int <i>stringcount</i>, const char *<i>stringname</i>,</b> -<b>const char **<i>stringptr</i>);</b> -</P> -<P> -<b>int pcre_get_stringnumber(const pcre *<i>code</i>,</b> -<b>const char *<i>name</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>int pcre_config(int <i>what</i>, void *<i>where</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> -<P> -<b>void *(*pcre_stack_malloc)(size_t);</b> -</P> -<P> -<b>void (*pcre_stack_free)(void *);</b> -</P> -<P> -<b>int (*pcre_callout)(pcre_callout_block *);</b> -</P> -<br><a name="SEC2" href="#TOC1">PCRE API OVERVIEW</a><br> -<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 -<a href="pcreposix.html"><b>pcreposix</b></a> -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</b>. It can -normally be accessed by adding <b>-lpcre</b> to the command for linking an -application that uses PCRE. 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 of PCRE. -</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. A sample program that -demonstrates the simplest way of using them is provided in the file called -<i>pcredemo.c</i> in the source distribution. The -<a href="pcresample.html"><b>pcresample</b></a> -documentation describes how to run it. -</P> -<P> -In addition to the main compiling and matching functions, there are convenience -functions for extracting captured substrings from a matched subject string. -They are: -<pre> - <b>pcre_copy_substring()</b> - <b>pcre_copy_named_substring()</b> - <b>pcre_get_substring()</b> - <b>pcre_get_named_substring()</b> - <b>pcre_get_substring_list()</b> - <b>pcre_get_stringnumber()</b> -</pre> -<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 to build a set of character tables -in the current locale for passing to <b>pcre_compile()</b> or <b>pcre_exec()</b>. -This is an optional facility that is provided for specialist use. Most -commonly, no special tables are passed, in which case internal tables that are -generated when PCRE is built are used. -</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 that 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> -<P> -The global variables <b>pcre_stack_malloc</b> and <b>pcre_stack_free</b> are also -indirections to memory management functions. These special functions are used -only when PCRE is compiled to use the heap for remembering data, instead of -recursive function calls. This is a non-standard way of building PCRE, for use -in environments that have limited stacks. Because of the greater use of memory -management, it runs more slowly. Separate functions are provided so that -special-purpose external code can be used for this case. When used, these -functions are always called in a stack-like manner (last obtained, first -freed), and always for memory blocks of the same size. -</P> -<P> -The global variable <b>pcre_callout</b> initially contains NULL. It can be set -by the caller to a "callout" function, which PCRE will then call at specified -points during a matching operation. Details are given in the -<a href="pcrecallout.html"><b>pcrecallout</b></a> -documentation. -</P> -<br><a name="SEC3" href="#TOC1">MULTITHREADING</a><br> -<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>, -<b>pcre_free</b>, <b>pcre_stack_malloc</b>, and <b>pcre_stack_free</b>, and the -callout function pointed to by <b>pcre_callout</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> -<br><a name="SEC4" href="#TOC1">SAVING PRECOMPILED PATTERNS FOR LATER USE</a><br> -<P> -The compiled form of a regular expression can be saved and re-used at a later -time, possibly by a different program, and even on a host other than the one on -which it was compiled. Details are given in the -<a href="pcreprecompile.html"><b>pcreprecompile</b></a> -documentation. -</P> -<br><a name="SEC5" href="#TOC1">CHECKING BUILD-TIME OPTIONS</a><br> -<P> -<b>int pcre_config(int <i>what</i>, void *<i>where</i>);</b> -</P> -<P> -The function <b>pcre_config()</b> makes it possible for a PCRE client to -discover which optional features have been compiled into the PCRE library. The -<a href="pcrebuild.html"><b>pcrebuild</b></a> -documentation has more details about these optional features. -</P> -<P> -The first argument for <b>pcre_config()</b> is an integer, specifying which -information is required; the second argument is a pointer to a variable into -which the information is placed. The following information is available: -<pre> - PCRE_CONFIG_UTF8 -</pre> -The output is an integer that is set to one if UTF-8 support is available; -otherwise it is set to zero. -<pre> - PCRE_CONFIG_UNICODE_PROPERTIES -</pre> -The output is an integer that is set to one if support for Unicode character -properties is available; otherwise it is set to zero. -<pre> - PCRE_CONFIG_NEWLINE -</pre> -The output is an integer that is set to the value of the code that is used for -the newline character. It is either linefeed (10) or carriage return (13), and -should normally be the standard character for your operating system. -<pre> - PCRE_CONFIG_LINK_SIZE -</pre> -The output is an integer that contains the number of bytes used for internal -linkage in compiled regular expressions. The value is 2, 3, or 4. Larger values -allow larger regular expressions to be compiled, at the expense of slower -matching. The default value of 2 is sufficient for all but the most massive -patterns, since it allows the compiled pattern to be up to 64K in size. -<pre> - PCRE_CONFIG_POSIX_MALLOC_THRESHOLD -</pre> -The output is an integer that contains the threshold above which the POSIX -interface uses <b>malloc()</b> for output vectors. Further details are given in -the -<a href="pcreposix.html"><b>pcreposix</b></a> -documentation. -<pre> - PCRE_CONFIG_MATCH_LIMIT -</pre> -The output is an integer that gives the default limit for the number of -internal matching function calls in a <b>pcre_exec()</b> execution. Further -details are given with <b>pcre_exec()</b> below. -<pre> - PCRE_CONFIG_STACKRECURSE -</pre> -The output is an integer that is set to one if internal recursion is -implemented by recursive function calls that use the stack to remember their -state. This is the usual way that PCRE is compiled. The output is zero if PCRE -was compiled to use blocks of data on the heap instead of recursive function -calls. In this case, <b>pcre_stack_malloc</b> and <b>pcre_stack_free</b> are -called to manage memory blocks on the heap, thus avoiding the use of the stack. -</P> -<br><a name="SEC6" href="#TOC1">COMPILING A PATTERN</a><br> -<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> -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 <i>pattern</i> argument. 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 the returned block; -this is a typedef for a structure whose contents are not externally defined. It -is up to the caller to free the memory when it is no longer required. -</P> -<P> -Although the compiled code of a PCRE regex is relocatable, that is, it does not -depend on memory location, the complete <b>pcre</b> data block is not -fully relocatable, because it may contain a copy of the <i>tableptr</i> -argument, which is an address (see below). -</P> -<P> -The <i>options</i> argument contains independent bits that affect the -compilation. It should be zero if no options are required. The available -options are described below. Some of them, in particular, those that are -compatible with Perl, can also be set and unset from within the pattern (see -the detailed description in the -<a href="pcrepattern.html"><b>pcrepattern</b></a> -documentation). 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 that are built when PCRE is compiled, using the default C -locale. Otherwise, <i>tableptr</i> must be an address that is the result of a -call to <b>pcre_maketables()</b>. This value is stored with the compiled -pattern, and used again by <b>pcre_exec()</b>, unless another table pointer is -passed to it. For more discussion, see the section on locale support below. -</P> -<P> -This code fragment shows a typical straightforward call to <b>pcre_compile()</b>: -<pre> - pcre *re; - const char *error; - int erroffset; - re = pcre_compile( - "^A.*Z", /* the pattern */ - 0, /* default options */ - &error, /* for error message */ - &erroffset, /* for error offset */ - NULL); /* use default character tables */ -</pre> -The following names for option bits are defined in the <b>pcre.h</b> header -file: -<pre> - PCRE_ANCHORED -</pre> -If this bit is set, the pattern is forced to be "anchored", that is, it is -constrained to match only at the first matching point in the string that 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. -<pre> - PCRE_AUTO_CALLOUT -</pre> -If this bit is set, <b>pcre_compile()</b> automatically inserts callout items, -all with number 255, before each pattern item. For discussion of the callout -facility, see the -<a href="pcrecallout.html"><b>pcrecallout</b></a> -documentation. -<pre> - PCRE_CASELESS -</pre> -If this bit is set, letters in the pattern match both upper and lower case -letters. It is equivalent to Perl's /i option, and it can be changed within a -pattern by a (?i) option setting. When running in UTF-8 mode, case support for -high-valued characters is available only when PCRE is built with Unicode -character property support. -<pre> - PCRE_DOLLAR_ENDONLY -</pre> -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, and no way to set it within -a pattern. -<pre> - PCRE_DOTALL -</pre> -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, and it can be changed within a pattern by a -(?s) option setting. A negative class such as [^a] always matches a newline -character, independent of the setting of this option. -<pre> - PCRE_EXTENDED -</pre> -If this bit is set, whitespace data characters in the pattern are totally -ignored except when escaped or inside a character class. Whitespace does not -include the VT character (code 11). In addition, 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 it can -be changed within a pattern by a (?x) option setting. -</P> -<P> -This option 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. -<pre> - PCRE_EXTRA -</pre> -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. -<pre> - PCRE_MULTILINE -</pre> -By default, PCRE treats the subject string as consisting of a single line of -characters (even if it actually contains 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, and it can be changed within a pattern by a (?m) option -setting. If there are no "\n" characters in a subject string, or no -occurrences of ^ or $ in a pattern, setting PCRE_MULTILINE has no effect. -<pre> - PCRE_NO_AUTO_CAPTURE -</pre> -If this option is set, it disables the use of numbered capturing parentheses in -the pattern. Any opening parenthesis that is not followed by ? behaves as if it -were followed by ?: but named parentheses can still be used for capturing (and -they acquire numbers in the usual way). There is no equivalent of this option -in Perl. -<pre> - PCRE_UNGREEDY -</pre> -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. -<pre> - PCRE_UTF8 -</pre> -This option causes PCRE to regard both the pattern and the subject as strings -of UTF-8 characters instead of single-byte character strings. However, it is -available only when PCRE is built to include UTF-8 support. If not, the use -of this option provokes an error. Details of how this option changes the -behaviour of PCRE are given in the -<a href="pcre.html#utf8support">section on UTF-8 support</a> -in the main -<a href="pcre.html"><b>pcre</b></a> -page. -<pre> - PCRE_NO_UTF8_CHECK -</pre> -When PCRE_UTF8 is set, the validity of the pattern as a UTF-8 string is -automatically checked. If an invalid UTF-8 sequence of bytes is found, -<b>pcre_compile()</b> returns an error. If you already know that your pattern is -valid, and you want to skip this check for performance reasons, you can set the -PCRE_NO_UTF8_CHECK option. When it is set, the effect of passing an invalid -UTF-8 string as a pattern is undefined. It may cause your program to crash. -Note that this option can also be passed to <b>pcre_exec()</b>, to suppress the -UTF-8 validity checking of subject strings. -</P> -<br><a name="SEC7" href="#TOC1">STUDYING A PATTERN</a><br> -<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> -If a compiled 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. If studying the pattern produces additional information that will -help speed up matching, <b>pcre_study()</b> returns a pointer to a -<b>pcre_extra</b> block, in which the <i>study_data</i> field points to the -results of the study. -</P> -<P> -The returned value from <b>pcre_study()</b> can be passed directly to -<b>pcre_exec()</b>. However, a <b>pcre_extra</b> block also contains other -fields that can be set by the caller before the block is passed; these are -described -<a href="#extradata">below</a> -in the section on matching a pattern. -</P> -<P> -If studying the pattern does not produce any additional information, -<b>pcre_study()</b> returns NULL. In that circumstance, if the calling program -wants to pass any of the other fields to <b>pcre_exec()</b>, it must set up its -own <b>pcre_extra</b> block. -</P> -<P> -The second argument of <b>pcre_study()</b> contains option bits. At present, no -options are defined, and this argument should always be zero. -</P> -<P> -The third argument for <b>pcre_study()</b> is a pointer for 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. You should -therefore test the error pointer for NULL after calling <b>pcre_study()</b>, to -be sure that it has run successfully. -</P> -<P> -This is a typical call to <b>pcre_study</b>(): -<pre> - pcre_extra *pe; - pe = pcre_study( - re, /* result of pcre_compile() */ - 0, /* no options exist */ - &error); /* set to NULL or points to a message */ -</pre> -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 -bytes is created. -<a name="localesupport"></a></P> -<br><a name="SEC8" href="#TOC1">LOCALE SUPPORT</a><br> -<P> -PCRE handles caseless matching, and determines whether characters are letters, -digits, or whatever, by reference to a set of tables, indexed by character -value. (When running in UTF-8 mode, this applies only to characters with codes -less than 128. Higher-valued codes never match escapes such as \w or \d, but -can be tested with \p if PCRE is built with Unicode character property -support.) -</P> -<P> -An internal set of tables is created in the default C locale when PCRE is -built. This is used when the final argument of <b>pcre_compile()</b> is NULL, -and is sufficient for many applications. An alternative set of tables can, -however, be supplied. These may be created in a different locale from the -default. As more and more applications change to using Unicode, the need for -this locale support is expected to die away. -</P> -<P> -External 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> or <b>pcre_exec()</b> as often as necessary. For -example, to build and use tables that are appropriate for the French locale -(where accented characters with values greater than 128 are treated as letters), -the following code could be used: -<pre> - setlocale(LC_CTYPE, "fr_FR"); - tables = pcre_maketables(); - re = pcre_compile(..., tables); -</pre> -When <b>pcre_maketables()</b> runs, the tables are built in memory that is -obtained via <b>pcre_malloc</b>. It is the caller's responsibility to ensure -that the memory containing the tables remains available for as long as it is -needed. -</P> -<P> -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 normally also by <b>pcre_exec()</b>. Thus, by default, for any single -pattern, compilation, studying and matching all happen in the same locale, but -different patterns can be compiled in different locales. -</P> -<P> -It is possible to pass a table pointer or NULL (indicating the use of the -internal tables) to <b>pcre_exec()</b>. Although not intended for this purpose, -this facility could be used to match a pattern in a different locale from the -one in which it was compiled. Passing table pointers at run time is discussed -below in the section on matching a pattern. -</P> -<br><a name="SEC9" href="#TOC1">INFORMATION ABOUT A PATTERN</a><br> -<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> -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, and 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: -<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> -The "magic number" is placed at the start of each compiled pattern as an simple -check against passing an arbitrary memory pointer. Here is a typical call of -<b>pcre_fullinfo()</b>, to obtain the length of the compiled pattern: -<pre> - int rc; - unsigned long int length; - rc = pcre_fullinfo( - re, /* result of pcre_compile() */ - pe, /* result of pcre_study(), or NULL */ - PCRE_INFO_SIZE, /* what is required */ - &length); /* where to put the data */ -</pre> -The possible values for the third argument are defined in <b>pcre.h</b>, and are -as follows: -<pre> - PCRE_INFO_BACKREFMAX -</pre> -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. -<pre> - PCRE_INFO_CAPTURECOUNT -</pre> -Return the number of capturing subpatterns in the pattern. The fourth argument -should point to an <b>int</b> variable. -<pre> - PCRE_INFO_DEFAULTTABLES -</pre> -Return a pointer to the internal default character tables within PCRE. The -fourth argument should point to an <b>unsigned char *</b> variable. This -information call is provided for internal use by the <b>pcre_study()</b> -function. External callers can cause PCRE to use its internal tables by passing -a NULL table pointer. -<pre> - PCRE_INFO_FIRSTBYTE -</pre> -Return information about the first byte of any matched string, for a -non-anchored pattern. (This option used to be called PCRE_INFO_FIRSTCHAR; the -old name is still recognized for backwards compatibility.) -</P> -<P> -If there is a fixed first byte, for example, from a pattern such as -(cat|cow|coyote), it is returned in the integer pointed to by <i>where</i>. -Otherwise, if either -<br> -<br> -(a) the pattern was compiled with the PCRE_MULTILINE option, and every branch -starts with "^", or -<br> -<br> -(b) every branch of the pattern starts with ".*" and PCRE_DOTALL is not set -(if it were set, the pattern would be anchored), -<br> -<br> --1 is returned, indicating that the pattern matches only at the start of a -subject string or after any newline within the string. Otherwise -2 is -returned. For anchored patterns, -2 is returned. -<pre> - PCRE_INFO_FIRSTTABLE -</pre> -If the pattern was studied, and this resulted in the construction of a 256-bit -table indicating a fixed set of bytes for the first byte 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. -<pre> - PCRE_INFO_LASTLITERAL -</pre> -Return the value of the rightmost literal byte that must exist in any matched -string, other than at its start, if such a byte has been recorded. The fourth -argument should point to an <b>int</b> variable. If there is no such byte, -1 is -returned. For anchored patterns, a last literal byte is recorded only if it -follows something of variable length. For example, for the pattern -/^a\d+z\d+/ the returned value is "z", but for /^a\dz\d/ the returned value -is -1. -<pre> - PCRE_INFO_NAMECOUNT - PCRE_INFO_NAMEENTRYSIZE - PCRE_INFO_NAMETABLE -</pre> -PCRE supports the use of named as well as numbered capturing parentheses. The -names are just an additional way of identifying the parentheses, which still -acquire numbers. A convenience function called <b>pcre_get_named_substring()</b> -is provided for extracting an individual captured substring by name. It is also -possible to extract the data directly, by first converting the name to a number -in order to access the correct pointers in the output vector (described with -<b>pcre_exec()</b> below). To do the conversion, you need to use the -name-to-number map, which is described by these three values. -</P> -<P> -The map consists of a number of fixed-size entries. PCRE_INFO_NAMECOUNT gives -the number of entries, and PCRE_INFO_NAMEENTRYSIZE gives the size of each -entry; both of these return an <b>int</b> value. The entry size depends on the -length of the longest name. PCRE_INFO_NAMETABLE returns a pointer to the first -entry of the table (a pointer to <b>char</b>). The first two bytes of each entry -are the number of the capturing parenthesis, most significant byte first. The -rest of the entry is the corresponding name, zero terminated. The names are in -alphabetical order. For example, consider the following pattern (assume -PCRE_EXTENDED is set, so white space - including newlines - is ignored): -<pre> - (?P<date> (?P<year>(\d\d)?\d\d) - (?P<month>\d\d) - (?P<day>\d\d) ) -</pre> -There are four named subpatterns, so the table has four entries, and each entry -in the table is eight bytes long. The table is as follows, with non-printing -bytes shows in hexadecimal, and undefined bytes shown as ??: -<pre> - 00 01 d a t e 00 ?? - 00 05 d a y 00 ?? ?? - 00 04 m o n t h 00 - 00 02 y e a r 00 ?? -</pre> -When writing code to extract data from named subpatterns using the -name-to-number map, remember that the length of each entry is likely to be -different for each compiled pattern. -<pre> - PCRE_INFO_OPTIONS -</pre> -Return a copy of the options with which the pattern was compiled. The fourth -argument should point to an <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. -</P> -<P> -A pattern is automatically anchored by PCRE if all of its top-level -alternatives begin with one of the following: -<pre> - ^ unless PCRE_MULTILINE is set - \A always - \G always - .* if PCRE_DOTALL is set and there are no back references to the subpattern in which .* appears -</pre> -For such patterns, the PCRE_ANCHORED bit is set in the options returned by -<b>pcre_fullinfo()</b>. -<pre> - PCRE_INFO_SIZE -</pre> -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. -<pre> - PCRE_INFO_STUDYSIZE -</pre> -Return the size of the data block pointed to by the <i>study_data</i> field in -a <b>pcre_extra</b> block. That is, it is the value that was passed to -<b>pcre_malloc()</b> when PCRE was getting memory into which to place the data -created by <b>pcre_study()</b>. The fourth argument should point to a -<b>size_t</b> variable. -</P> -<br><a name="SEC10" href="#TOC1">OBSOLETE INFO FUNCTION</a><br> -<P> -<b>int pcre_info(const pcre *<i>code</i>, int *<i>optptr</i>, int</b> -<b>*<i>firstcharptr</i>);</b> -</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: -<pre> - PCRE_ERROR_NULL the argument <i>code</i> was NULL - PCRE_ERROR_BADMAGIC the "magic number" was not found -</pre> -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_FIRSTBYTE above). -</P> -<br><a name="SEC11" href="#TOC1">MATCHING A PATTERN</a><br> -<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> -The function <b>pcre_exec()</b> is called to match a subject string against a -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. -</P> -<P> -In most applications, the pattern will have been compiled (and optionally -studied) in the same process that calls <b>pcre_exec()</b>. However, it is -possible to save compiled patterns and study data, and then use them later -in different processes, possibly even on different hosts. For a discussion -about this, see the -<a href="pcreprecompile.html"><b>pcreprecompile</b></a> -documentation. -</P> -<P> -Here is an example of a simple call to <b>pcre_exec()</b>: -<pre> - int rc; - int ovector[30]; - rc = pcre_exec( - re, /* result of pcre_compile() */ - NULL, /* we didn't study the pattern */ - "some string", /* the subject string */ - 11, /* the length of the subject string */ - 0, /* start at offset 0 in the subject */ - 0, /* default options */ - ovector, /* vector of integers for substring information */ - 30); /* number of elements in the vector (NOT size in bytes) */ -<a name="extradata"></a></PRE> -</P> -<br><b> -Extra data for <b>pcre_exec()</b> -</b><br> -<P> -If the <i>extra</i> argument is not NULL, it must point to a <b>pcre_extra</b> -data block. The <b>pcre_study()</b> function returns such a block (when it -doesn't return NULL), but you can also create one for yourself, and pass -additional information in it. The fields in a <b>pcre_extra</b> block are as -follows: -<pre> - unsigned long int <i>flags</i>; - void *<i>study_data</i>; - unsigned long int <i>match_limit</i>; - void *<i>callout_data</i>; - const unsigned char *<i>tables</i>; -</pre> -The <i>flags</i> field is a bitmap that specifies which of the other fields -are set. The flag bits are: -<pre> - PCRE_EXTRA_STUDY_DATA - PCRE_EXTRA_MATCH_LIMIT - PCRE_EXTRA_CALLOUT_DATA - PCRE_EXTRA_TABLES -</pre> -Other flag bits should be set to zero. The <i>study_data</i> field is set in the -<b>pcre_extra</b> block that is returned by <b>pcre_study()</b>, together with -the appropriate flag bit. You should not set this yourself, but you may add to -the block by setting the other fields and their corresponding flag bits. -</P> -<P> -The <i>match_limit</i> field provides a means of preventing PCRE from using up a -vast amount of resources when running patterns that are not going to match, -but which have a very large number of possibilities in their search trees. The -classic example is the use of nested unlimited repeats. -</P> -<P> -Internally, PCRE uses a function called <b>match()</b> which it calls repeatedly -(sometimes recursively). The limit is imposed on the number of times this -function is called during a match, which has the effect of limiting the amount -of recursion and backtracking that can take place. For patterns that are not -anchored, the count starts from zero for each position in the subject string. -</P> -<P> -The default limit for the library can be set when PCRE is built; the default -default is 10 million, which handles all but the most extreme cases. You can -reduce the default by suppling <b>pcre_exec()</b> with a <b>pcre_extra</b> block -in which <i>match_limit</i> is set to a smaller value, and -PCRE_EXTRA_MATCH_LIMIT is set in the <i>flags</i> field. If the limit is -exceeded, <b>pcre_exec()</b> returns PCRE_ERROR_MATCHLIMIT. -</P> -<P> -The <i>pcre_callout</i> field is used in conjunction with the "callout" feature, -which is described in the -<a href="pcrecallout.html"><b>pcrecallout</b></a> -documentation. -</P> -<P> -The <i>tables</i> field is used to pass a character tables pointer to -<b>pcre_exec()</b>; this overrides the value that is stored with the compiled -pattern. A non-NULL value is stored with the compiled pattern only if custom -tables were supplied to <b>pcre_compile()</b> via its <i>tableptr</i> argument. -If NULL is passed to <b>pcre_exec()</b> using this mechanism, it forces PCRE's -internal tables to be used. This facility is helpful when re-using patterns -that have been saved after compiling with an external set of tables, because -the external tables might be at a different address when <b>pcre_exec()</b> is -called. See the -<a href="pcreprecompile.html"><b>pcreprecompile</b></a> -documentation for a discussion of saving compiled patterns for later use. -</P> -<br><b> -Option bits for <b>pcre_exec()</b> -</b><br> -<P> -The unused bits of the <i>options</i> argument for <b>pcre_exec()</b> must be -zero. The only bits that may be set are PCRE_ANCHORED, PCRE_NOTBOL, -PCRE_NOTEOL, PCRE_NOTEMPTY, PCRE_NO_UTF8_CHECK and PCRE_PARTIAL. -<pre> - PCRE_ANCHORED -</pre> -The PCRE_ANCHORED option limits <b>pcre_exec()</b> to matching at the first -matching position. 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. -<pre> - PCRE_NOTBOL -</pre> -This option specifies that first character of the subject 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. This option affects only the behaviour of the circumflex -metacharacter. It does not affect \A. -<pre> - PCRE_NOTEOL -</pre> -This option specifies that the end of the subject 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. This option affects only the -behaviour of the dollar metacharacter. It does not affect \Z or \z. -<pre> - PCRE_NOTEMPTY -</pre> -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 -<pre> - a?b? -</pre> -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 and PCRE_ANCHORED, and then if that fails by advancing the -starting offset (see below) and trying an ordinary match again. There is some -code that demonstrates how to do this in the <i>pcredemo.c</i> sample program. -<pre> - PCRE_NO_UTF8_CHECK -</pre> -When PCRE_UTF8 is set at compile time, the validity of the subject as a UTF-8 -string is automatically checked when <b>pcre_exec()</b> is subsequently called. -The value of <i>startoffset</i> is also checked to ensure that it points to the -start of a UTF-8 character. If an invalid UTF-8 sequence of bytes is found, -<b>pcre_exec()</b> returns the error PCRE_ERROR_BADUTF8. If <i>startoffset</i> -contains an invalid value, PCRE_ERROR_BADUTF8_OFFSET is returned. -</P> -<P> -If you already know that your subject is valid, and you want to skip these -checks for performance reasons, you can set the PCRE_NO_UTF8_CHECK option when -calling <b>pcre_exec()</b>. You might want to do this for the second and -subsequent calls to <b>pcre_exec()</b> if you are making repeated calls to find -all the matches in a single subject string. However, you should be sure that -the value of <i>startoffset</i> points to the start of a UTF-8 character. When -PCRE_NO_UTF8_CHECK is set, the effect of passing an invalid UTF-8 string as a -subject, or a value of <i>startoffset</i> that does not point to the start of a -UTF-8 character, is undefined. Your program may crash. -<pre> - PCRE_PARTIAL -</pre> -This option turns on the partial matching feature. If the subject string fails -to match the pattern, but at some point during the matching process the end of -the subject was reached (that is, the subject partially matches the pattern and -the failure to match occurred only because there were not enough subject -characters), <b>pcre_exec()</b> returns PCRE_ERROR_PARTIAL instead of -PCRE_ERROR_NOMATCH. When PCRE_PARTIAL is used, there are restrictions on what -may appear in the pattern. These are discussed in the -<a href="pcrepartial.html"><b>pcrepartial</b></a> -documentation. -</P> -<br><b> -The string to be matched by <b>pcre_exec()</b> -</b><br> -<P> -The subject string is passed to <b>pcre_exec()</b> as a pointer in -<i>subject</i>, a length in <i>length</i>, and a starting byte offset in -<i>startoffset</i>. In UTF-8 mode, the byte offset must point to the start of a -UTF-8 character. Unlike the pattern string, the subject may contain binary zero -bytes. 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 -<pre> - \Biss\B -</pre> -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 made. This can only succeed if the -pattern does not require the match to be at the start of the subject. -</P> -<br><b> -How <b>pcre_exec()</b> returns captured substrings -</b><br> -<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>, which must be a non-negative number. <b>Note</b>: -this argument is NOT the size of <i>ovector</i> in bytes. -</P> -<P> -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 is 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 is returned. -</P> -<P> -If the vector is too small to hold all the captured substring offsets, 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> is not 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> -<br><b> -Return values from <b>pcre_exec()</b> -</b><br> -<P> -If <b>pcre_exec()</b> fails, it returns a negative number. The following are -defined in the header file: -<pre> - PCRE_ERROR_NOMATCH (-1) -</pre> -The subject string did not match the pattern. -<pre> - PCRE_ERROR_NULL (-2) -</pre> -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. -<pre> - PCRE_ERROR_BADOPTION (-3) -</pre> -An unrecognized bit was set in the <i>options</i> argument. -<pre> - PCRE_ERROR_BADMAGIC (-4) -</pre> -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 and to detect when a pattern that was -compiled in an environment of one endianness is run in an environment with the -other endianness. This is the error that PCRE gives when the magic number is -not present. -<pre> - PCRE_ERROR_UNKNOWN_NODE (-5) -</pre> -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. -<pre> - PCRE_ERROR_NOMEMORY (-6) -</pre> -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 -automatically freed at the end of matching. -<pre> - PCRE_ERROR_NOSUBSTRING (-7) -</pre> -This error is used by the <b>pcre_copy_substring()</b>, -<b>pcre_get_substring()</b>, and <b>pcre_get_substring_list()</b> functions (see -below). It is never returned by <b>pcre_exec()</b>. -<pre> - PCRE_ERROR_MATCHLIMIT (-8) -</pre> -The recursion and backtracking limit, as specified by the <i>match_limit</i> -field in a <b>pcre_extra</b> structure (or defaulted) was reached. See the -description above. -<pre> - PCRE_ERROR_CALLOUT (-9) -</pre> -This error is never generated by <b>pcre_exec()</b> itself. It is provided for -use by callout functions that want to yield a distinctive error code. See the -<a href="pcrecallout.html"><b>pcrecallout</b></a> -documentation for details. -<pre> - PCRE_ERROR_BADUTF8 (-10) -</pre> -A string that contains an invalid UTF-8 byte sequence was passed as a subject. -<pre> - PCRE_ERROR_BADUTF8_OFFSET (-11) -</pre> -The UTF-8 byte sequence that was passed as a subject was valid, but the value -of <i>startoffset</i> did not point to the beginning of a UTF-8 character. -<pre> - PCRE_ERROR_PARTIAL (-12) -</pre> -The subject string did not match, but it did match partially. See the -<a href="pcrepartial.html"><b>pcrepartial</b></a> -documentation for details of partial matching. -<pre> - PCRE_ERROR_BAD_PARTIAL (-13) -</pre> -The PCRE_PARTIAL option was used with a compiled pattern containing items that -are not supported for partial matching. See the -<a href="pcrepartial.html"><b>pcrepartial</b></a> -documentation for details of partial matching. -<pre> - PCRE_ERROR_INTERNAL (-14) -</pre> -An unexpected internal error has occurred. This error could be caused by a bug -in PCRE or by overwriting of the compiled pattern. -<pre> - PCRE_ERROR_BADCOUNT (-15) -</pre> -This error is given if the value of the <i>ovecsize</i> argument is negative. -</P> -<br><a name="SEC12" href="#TOC1">EXTRACTING CAPTURED SUBSTRINGS BY NUMBER</a><br> -<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> -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. These functions identify substrings -by number. The next section describes functions for extracting named -substrings. A substring that contains a binary zero is correctly extracted and -has a further zero added on the end, but the result is not, of course, -a C string. -</P> -<P> -The first three arguments are the same for all three of these functions: -<i>subject</i> is the subject string that 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 -number of elements in 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, whereas -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 -<pre> - PCRE_ERROR_NOMEMORY (-6) -</pre> -The buffer was too small for <b>pcre_copy_substring()</b>, or the attempt to get -memory failed for <b>pcre_get_substring()</b>. -<pre> - PCRE_ERROR_NOSUBSTRING (-7) -</pre> -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 that 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 -<pre> - PCRE_ERROR_NOMEMORY (-6) -</pre> -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> -<br><a name="SEC13" href="#TOC1">EXTRACTING CAPTURED SUBSTRINGS BY NAME</a><br> -<P> -<b>int pcre_get_stringnumber(const pcre *<i>code</i>,</b> -<b>const char *<i>name</i>);</b> -</P> -<P> -<b>int pcre_copy_named_substring(const pcre *<i>code</i>,</b> -<b>const char *<i>subject</i>, int *<i>ovector</i>,</b> -<b>int <i>stringcount</i>, const char *<i>stringname</i>,</b> -<b>char *<i>buffer</i>, int <i>buffersize</i>);</b> -</P> -<P> -<b>int pcre_get_named_substring(const pcre *<i>code</i>,</b> -<b>const char *<i>subject</i>, int *<i>ovector</i>,</b> -<b>int <i>stringcount</i>, const char *<i>stringname</i>,</b> -<b>const char **<i>stringptr</i>);</b> -</P> -<P> -To extract a substring by name, you first have to find associated number. -For example, for this pattern -<pre> - (a+)b(?<xxx>\d+)... -</pre> -the number of the subpattern called "xxx" is 2. You can find the number from -the name by calling <b>pcre_get_stringnumber()</b>. The first argument is the -compiled pattern, and the second is the name. The yield of the function is the -subpattern number, or PCRE_ERROR_NOSUBSTRING (-7) if there is no subpattern of -that name. -</P> -<P> -Given the number, you can extract the substring directly, or use one of the -functions described in the previous section. For convenience, there are also -two functions that do the whole job. -</P> -<P> -Most of the arguments of <i>pcre_copy_named_substring()</i> and -<i>pcre_get_named_substring()</i> are the same as those for the similarly named -functions that extract by number. As these are described in the previous -section, they are not re-described here. There are just two differences: -</P> -<P> -First, instead of a substring number, a substring name is given. Second, there -is an extra argument, given at the start, which is a pointer to the compiled -pattern. This is needed in order to gain access to the name-to-number -translation table. -</P> -<P> -These functions call <b>pcre_get_stringnumber()</b>, and if it succeeds, they -then call <i>pcre_copy_substring()</i> or <i>pcre_get_substring()</i>, as -appropriate. -</P> -<P> -Last updated: 09 September 2004 -<br> -Copyright © 1997-2004 University of Cambridge. -<p> -Return to the <a href="index.html">PCRE index page</a>. -</p> |