diff options
Diffstat (limited to 'pcre/doc/html/pcreapi.html')
| -rw-r--r-- | pcre/doc/html/pcreapi.html | 423 |
1 files changed, 236 insertions, 187 deletions
diff --git a/pcre/doc/html/pcreapi.html b/pcre/doc/html/pcreapi.html index 2a00d9ba041..abc3d2663fc 100644 --- a/pcre/doc/html/pcreapi.html +++ b/pcre/doc/html/pcreapi.html @@ -46,125 +46,125 @@ man page, in case the conversion went wrong. <br><a name="SEC1" href="#TOC1">PCRE NATIVE API BASIC FUNCTIONS</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> +<b> const char **<i>errptr</i>, int *<i>erroffset</i>,</b> +<b> const unsigned char *<i>tableptr</i>);</b> +<br> +<br> <b>pcre *pcre_compile2(const char *<i>pattern</i>, int <i>options</i>,</b> -<b>int *<i>errorcodeptr</i>,</b> -<b>const char **<i>errptr</i>, int *<i>erroffset</i>,</b> -<b>const unsigned char *<i>tableptr</i>);</b> -</P> -<P> +<b> int *<i>errorcodeptr</i>,</b> +<b> const char **<i>errptr</i>, int *<i>erroffset</i>,</b> +<b> const unsigned char *<i>tableptr</i>);</b> +<br> +<br> <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> const char **<i>errptr</i>);</b> +<br> +<br> <b>void pcre_free_study(pcre_extra *<i>extra</i>);</b> -</P> -<P> +<br> +<br> <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> 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> +<br> +<br> <b>int pcre_dfa_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> -<b>int *<i>workspace</i>, int <i>wscount</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> +<b> int *<i>workspace</i>, int <i>wscount</i>);</b> </P> <br><a name="SEC2" href="#TOC1">PCRE NATIVE API STRING EXTRACTION FUNCTIONS</a><br> <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> 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> +<br> +<br> <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 <i>stringcount</i>, int <i>stringnumber</i>, char *<i>buffer</i>,</b> +<b> int <i>buffersize</i>);</b> +<br> +<br> <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> 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> +<br> +<br> <b>int pcre_get_stringnumber(const pcre *<i>code</i>,</b> -<b>const char *<i>name</i>);</b> -</P> -<P> +<b> const char *<i>name</i>);</b> +<br> +<br> <b>int pcre_get_stringtable_entries(const pcre *<i>code</i>,</b> -<b>const char *<i>name</i>, char **<i>first</i>, char **<i>last</i>);</b> -</P> -<P> +<b> const char *<i>name</i>, char **<i>first</i>, char **<i>last</i>);</b> +<br> +<br> <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 <i>stringcount</i>, int <i>stringnumber</i>,</b> +<b> const char **<i>stringptr</i>);</b> +<br> +<br> <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> int *<i>ovector</i>, int <i>stringcount</i>, const char ***<i>listptr</i>);</b> +<br> +<br> <b>void pcre_free_substring(const char *<i>stringptr</i>);</b> -</P> -<P> +<br> +<br> <b>void pcre_free_substring_list(const char **<i>stringptr</i>);</b> </P> <br><a name="SEC3" href="#TOC1">PCRE NATIVE API AUXILIARY FUNCTIONS</a><br> <P> <b>int pcre_jit_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> -<b>pcre_jit_stack *<i>jstack</i>);</b> -</P> -<P> +<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> +<b> pcre_jit_stack *<i>jstack</i>);</b> +<br> +<br> <b>pcre_jit_stack *pcre_jit_stack_alloc(int <i>startsize</i>, int <i>maxsize</i>);</b> -</P> -<P> +<br> +<br> <b>void pcre_jit_stack_free(pcre_jit_stack *<i>stack</i>);</b> -</P> -<P> +<br> +<br> <b>void pcre_assign_jit_stack(pcre_extra *<i>extra</i>,</b> -<b>pcre_jit_callback <i>callback</i>, void *<i>data</i>);</b> -</P> -<P> +<b> pcre_jit_callback <i>callback</i>, void *<i>data</i>);</b> +<br> +<br> <b>const unsigned char *pcre_maketables(void);</b> -</P> -<P> +<br> +<br> <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 <i>what</i>, void *<i>where</i>);</b> +<br> +<br> <b>int pcre_refcount(pcre *<i>code</i>, int <i>adjust</i>);</b> -</P> -<P> +<br> +<br> <b>int pcre_config(int <i>what</i>, void *<i>where</i>);</b> -</P> -<P> +<br> +<br> <b>const char *pcre_version(void);</b> -</P> -<P> +<br> +<br> <b>int pcre_pattern_to_host_byte_order(pcre *<i>code</i>,</b> -<b>pcre_extra *<i>extra</i>, const unsigned char *<i>tables</i>);</b> +<b> pcre_extra *<i>extra</i>, const unsigned char *<i>tables</i>);</b> </P> <br><a name="SEC4" href="#TOC1">PCRE NATIVE API INDIRECTED FUNCTIONS</a><br> <P> <b>void *(*pcre_malloc)(size_t);</b> -</P> -<P> +<br> +<br> <b>void (*pcre_free)(void *);</b> -</P> -<P> +<br> +<br> <b>void *(*pcre_stack_malloc)(size_t);</b> -</P> -<P> +<br> +<br> <b>void (*pcre_stack_free)(void *);</b> -</P> -<P> +<br> +<br> <b>int (*pcre_callout)(pcre_callout_block *);</b> </P> <br><a name="SEC5" href="#TOC1">PCRE 8-BIT, 16-BIT, AND 32-BIT LIBRARIES</a><br> @@ -484,6 +484,13 @@ the <a href="pcreposix.html"><b>pcreposix</b></a> documentation. <pre> + PCRE_CONFIG_PARENS_LIMIT +</pre> +The output is a long integer that gives the maximum depth of nesting of +parentheses (of any kind) in a pattern. This limit is imposed to cap the amount +of system stack used when a pattern is compiled. It is specified when PCRE is +built; the default is 250. +<pre> PCRE_CONFIG_MATCH_LIMIT </pre> The output is a long integer that gives the default limit for the number of @@ -509,12 +516,14 @@ avoiding the use of the stack. <br><a name="SEC11" 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> +<b> const char **<i>errptr</i>, int *<i>erroffset</i>,</b> +<b> const unsigned char *<i>tableptr</i>);</b> +<br> +<br> <b>pcre *pcre_compile2(const char *<i>pattern</i>, int <i>options</i>,</b> -<b>int *<i>errorcodeptr</i>,</b> -<b>const char **<i>errptr</i>, int *<i>erroffset</i>,</b> -<b>const unsigned char *<i>tableptr</i>);</b> +<b> int *<i>errorcodeptr</i>,</b> +<b> const char **<i>errptr</i>, int *<i>erroffset</i>,</b> +<b> const unsigned char *<i>tableptr</i>);</b> </P> <P> Either of the functions <b>pcre_compile()</b> or <b>pcre_compile2()</b> can be @@ -580,8 +589,9 @@ 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. +pattern, and used again by <b>pcre_exec()</b> and <b>pcre_dfa_exec()</b> when the +pattern is matched. 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>: @@ -666,12 +676,24 @@ documentation. <pre> PCRE_EXTENDED </pre> -If this bit is set, white space data characters in the pattern are totally -ignored except when escaped or inside a character class. White space does not -include the VT character (code 11). In addition, characters between an -unescaped # outside a character class and the next newline, 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. +If this bit is set, most white space characters in the pattern are totally +ignored except when escaped or inside a character class. However, white space +is not allowed within sequences such as (?> that introduce various +parenthesized subpatterns, nor within a numerical quantifier such as {1,3}. +However, ignorable white space is permitted between an item and a following +quantifier and between a quantifier and a following + that indicates +possessiveness. +</P> +<P> +White space did not used to include the VT character (code 11), because Perl +did not treat this character as white space. However, Perl changed at release +5.18, so PCRE followed at release 8.34, and VT is now treated as white space. +</P> +<P> +PCRE_EXTENDED also causes characters between an unescaped # outside a character +class and the next newline, inclusive, to be ignored. PCRE_EXTENDED is +equivalent to Perl's /x option, and it can be changed within a pattern by a +(?x) option setting. </P> <P> Which characters are interpreted as newlines is controlled by the options @@ -825,6 +847,15 @@ 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_NO_AUTO_POSSESS +</pre> +If this option is set, it disables "auto-possessification". This is an +optimization that, for example, turns a+b into a++b in order to avoid +backtracks into a+ that can never be successful. However, if callouts are in +use, auto-possessification means that some of them are never taken. You can set +this option if you want the matching functions to do a full unoptimized search +and run all the callouts, but it is mainly provided for testing purposes. +<pre> PCRE_NO_START_OPTIMIZE </pre> This is an option that acts at matching time; that is, it is really an option @@ -875,10 +906,10 @@ page. If an invalid UTF-8 sequence 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> and <b>pcre_dfa_exec()</b>, to suppress the -validity checking of subject strings only. If the same string is being matched -many times, the option can be safely set for the second and subsequent +undefined. It may cause your program to crash or loop. Note that this option +can also be passed to <b>pcre_exec()</b> and <b>pcre_dfa_exec()</b>, to suppress +the validity checking of subject strings only. If the same string is being +matched many times, the option can be safely set for the second and subsequent matchings to improve performance. </P> <br><a name="SEC12" href="#TOC1">COMPILATION ERROR CODES</a><br> @@ -923,7 +954,7 @@ have fallen out of use. To avoid confusion, they have not been re-used. 31 POSIX collating elements are not supported 32 this version of PCRE is compiled without UTF support 33 [this code is not in use] - 34 character value in \x{...} sequence is too large + 34 character value in \x{} or \o{} is too large 35 invalid condition (?(0) 36 \C not allowed in lookbehind assertion 37 PCRE does not support \L, \l, \N{name}, \U, or \u @@ -971,14 +1002,20 @@ have fallen out of use. To avoid confusion, they have not been re-used. 75 name is too long in (*MARK), (*PRUNE), (*SKIP), or (*THEN) 76 character value in \u.... sequence is too large 77 invalid UTF-32 string (specifically UTF-32) + 78 setting UTF is disabled by the application + 79 non-hex character in \x{} (closing brace missing?) + 80 non-octal character in \o{} (closing brace missing?) + 81 missing opening brace after \o + 82 parentheses are too deeply nested + 83 invalid range in character class </pre> The numbers 32 and 10000 in errors 48 and 49 are defaults; different values may be used if the limits were changed when PCRE was built. <a name="studyingapattern"></a></P> <br><a name="SEC13" 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> +<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 @@ -1101,15 +1138,18 @@ There is a longer discussion of PCRE_NO_START_OPTIMIZE <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. By default, higher-valued codes never match escapes -such as \w or \d, but they can be tested with \p if PCRE is built with -Unicode character property support. Alternatively, the PCRE_UCP option can be -set at compile time; this causes \w and friends to use Unicode property -support instead of built-in tables. The use of locales with Unicode is -discouraged. If you are handling characters with codes greater than 128, you -should either use UTF-8 and Unicode, or use locales, but not try to mix the -two. +code point. When running in UTF-8 mode, or in the 16- or 32-bit libraries, this +applies only to characters with code points less than 256. By default, +higher-valued code points never match escapes such as \w or \d. However, if +PCRE is built with Unicode property support, all characters can be tested with +\p and \P, or, alternatively, the PCRE_UCP option can be set when a pattern +is compiled; this causes \w and friends to use Unicode property support +instead of the built-in tables. +</P> +<P> +The use of locales with Unicode is discouraged. If you are handling characters +with code points greater than 128, you should either use Unicode support, or +use locales, but not try to mix the two. </P> <P> PCRE contains an internal set of tables that are used when the final argument @@ -1127,10 +1167,10 @@ for this locale support is expected to die away. <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: +to <b>pcre_compile()</b> as often as necessary. For example, to build and use +tables that are appropriate for the French locale (where accented characters +with values greater than 128 are treated as letters), the following code could +be used: <pre> setlocale(LC_CTYPE, "fr_FR"); tables = pcre_maketables(); @@ -1148,21 +1188,25 @@ needed. <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 +and also by <b>pcre_exec()</b> and <b>pcre_dfa_exec()</b>. Thus, for any single pattern, compilation, studying and matching all happen in the same locale, but -different patterns can be compiled in different locales. +different patterns can be processed 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. +internal tables) to <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b> (see the +discussion below in the section on matching a pattern). This facility is +provided for use with pre-compiled patterns that have been saved and reloaded. +Character tables are not saved with patterns, so if a non-standard table was +used at compile time, it must be provided again when the reloaded pattern is +matched. Attempting to use this facility to match a pattern in a different +locale from the one in which it was compiled is likely to lead to anomalous +(usually incorrect) results. <a name="infoaboutpattern"></a></P> <br><a name="SEC15" 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> +<b> int <i>what</i>, void *<i>where</i>);</b> </P> <P> The <b>pcre_fullinfo()</b> function returns information about a compiled @@ -1303,10 +1347,15 @@ is -1. </P> <P> Since for the 32-bit library using the non-UTF-32 mode, this function is unable -to return the full 32-bit range of the character, this value is deprecated; +to return the full 32-bit range of characters, this value is deprecated; instead the PCRE_INFO_REQUIREDCHARFLAGS and PCRE_INFO_REQUIREDCHAR values should be used. <pre> + PCRE_INFO_MATCH_EMPTY +</pre> +Return 1 if the pattern can match an empty string, otherwise 0. The fourth +argument should point to an <b>int</b> variable. +<pre> PCRE_INFO_MATCHLIMIT </pre> If the pattern set a match limit by including an item of the form @@ -1364,16 +1413,18 @@ contains the parenthesis number. The rest of the entry is the corresponding name, zero terminated. </P> <P> -The names are in alphabetical order. Duplicate names may appear if (?| is used -to create multiple groups with the same number, as described in the +The names are in alphabetical order. If (?| is used to create multiple groups +with the same number, as described in the <a href="pcrepattern.html#dupsubpatternnumber">section on duplicate subpattern numbers</a> in the <a href="pcrepattern.html"><b>pcrepattern</b></a> -page. Duplicate names for subpatterns with different numbers are permitted only -if PCRE_DUPNAMES is set. In all cases of duplicate names, they appear in the -table in the order in which they were found in the pattern. In the absence of -(?| this is the order of increasing number; when (?| is used this is not -necessarily the case because later subpatterns may have lower numbers. +page, the groups may be given the same name, but there is only one entry in the +table. Different names for groups of the same number are not permitted. +Duplicate names for subpatterns with different numbers are permitted, +but only if PCRE_DUPNAMES is set. They appear in the table in the order in +which they were found in the pattern. In the absence of (?| this is the order +of increasing number; when (?| is used this is not necessarily the case because +later subpatterns may have lower numbers. </P> <P> As a simple example of the name/number table, consider the following pattern @@ -1487,30 +1538,14 @@ returned. For anchored patterns, 0 is returned. <pre> PCRE_INFO_FIRSTCHARACTER </pre> -Return the fixed first character value, if PCRE_INFO_FIRSTCHARACTERFLAGS -returned 1; otherwise returns 0. The fourth argument should point to an -<b>uint_t</b> variable. +Return the fixed first character value in the situation where +PCRE_INFO_FIRSTCHARACTERFLAGS returns 1; otherwise return 0. The fourth +argument should point to an <b>uint_t</b> variable. </P> <P> In the 8-bit library, the value is always less than 256. In the 16-bit library the value can be up to 0xffff. In the 32-bit library in UTF-32 mode the value can be up to 0x10ffff, and up to 0xffffffff when not using UTF-32 mode. -</P> -<P> -If there is no fixed first value, and 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_REQUIREDCHARFLAGS </pre> @@ -1559,8 +1594,8 @@ is different. (This seems a highly unlikely scenario.) <br><a name="SEC17" href="#TOC1">MATCHING A PATTERN: THE TRADITIONAL FUNCTION</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> +<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 @@ -1723,17 +1758,22 @@ and is described in the 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 +The <i>tables</i> field is provided for use with patterns that have been +pre-compiled using custom character tables, saved to disc or elsewhere, and +then reloaded, because the tables that were used to compile a pattern are not +saved with it. See the <a href="pcreprecompile.html"><b>pcreprecompile</b></a> -documentation for a discussion of saving compiled patterns for later use. +documentation for a discussion of saving compiled patterns for later use. If +NULL is passed using this mechanism, it forces PCRE's internal tables to be +used. +</P> +<P> +<b>Warning:</b> The tables that <b>pcre_exec()</b> uses must be the same as those +that were used when the pattern was compiled. If this is not the case, the +behaviour of <b>pcre_exec()</b> is undefined. Therefore, when a pattern is +compiled and matched in the same process, this field should never be set. In +this (the most common) case, the correct table pointer is automatically passed +with the compiled pattern from <b>pcre_compile()</b> to <b>pcre_exec()</b>. </P> <P> If PCRE_EXTRA_MARK is set in the <i>flags</i> field, the <i>mark</i> field must @@ -1951,7 +1991,7 @@ 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 character (or the end of the subject). When PCRE_NO_UTF8_CHECK is set, the effect of passing an invalid string as a subject or an invalid value of <i>startoffset</i> is -undefined. Your program may crash. +undefined. Your program may crash or loop. <pre> PCRE_PARTIAL_HARD PCRE_PARTIAL_SOFT @@ -2413,17 +2453,17 @@ no longer in use and is never returned. <br><a name="SEC18" 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 <i>stringcount</i>, int <i>stringnumber</i>, char *<i>buffer</i>,</b> +<b> int <i>buffersize</i>);</b> +<br> +<br> <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 <i>stringcount</i>, int <i>stringnumber</i>,</b> +<b> const char **<i>stringptr</i>);</b> +<br> +<br> <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> +<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 @@ -2508,19 +2548,19 @@ provided. <br><a name="SEC19" 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> const char *<i>name</i>);</b> +<br> +<br> <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> 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> +<br> +<br> <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> +<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. @@ -2572,7 +2612,7 @@ same number causes an error at compile time. <br><a name="SEC20" href="#TOC1">DUPLICATE SUBPATTERN NAMES</a><br> <P> <b>int pcre_get_stringtable_entries(const pcre *<i>code</i>,</b> -<b>const char *<i>name</i>, char **<i>first</i>, char **<i>last</i>);</b> +<b> const char *<i>name</i>, char **<i>first</i>, char **<i>last</i>);</b> </P> <P> When a pattern is compiled with the PCRE_DUPNAMES option, names for subpatterns @@ -2653,9 +2693,9 @@ the value returned is the size of each block that is obtained from the heap. <br><a name="SEC23" href="#TOC1">MATCHING A PATTERN: THE ALTERNATIVE FUNCTION</a><br> <P> <b>int pcre_dfa_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> -<b>int *<i>workspace</i>, int <i>wscount</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> +<b> int *<i>workspace</i>, int <i>wscount</i>);</b> </P> <P> The function <b>pcre_dfa_exec()</b> is called to match a subject string against @@ -2784,6 +2824,15 @@ matching string is given first. If there were too many matches to fit into the longest matches. Unlike <b>pcre_exec()</b>, <b>pcre_dfa_exec()</b> can use the entire <i>ovector</i> for returning matched strings. </P> +<P> +NOTE: PCRE's "auto-possessification" optimization usually applies to character +repeats at the end of a pattern (as well as internally). For example, the +pattern "a\d+" is compiled as if it were "a\d++" because there is no point +even considering the possibility of backtracking into the repeated digits. For +DFA matching, this means that only one possible match is found. If you really +do want multiple matches in such cases, either use an ungreedy repeat +("a\d+?") or set the PCRE_NO_AUTO_POSSESS option when compiling. +</P> <br><b> Error returns from <b>pcre_dfa_exec()</b> </b><br> @@ -2850,7 +2899,7 @@ Cambridge CB2 3QH, England. </P> <br><a name="SEC26" href="#TOC1">REVISION</a><br> <P> -Last updated: 12 May 2013 +Last updated: 12 November 2013 <br> Copyright © 1997-2013 University of Cambridge. <br> |