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# Line 1  Line 1 
1  .TH PCREAPI 3  .TH PCREAPI 3 "28 August 2012" "PCRE 8.32"
2  .SH NAME  .SH NAME
3  PCRE - Perl-compatible regular expressions  PCRE - Perl-compatible regular expressions
 .SH "PCRE NATIVE API"  
 .rs  
4  .sp  .sp
5  .B #include <pcre.h>  .B #include <pcre.h>
6  .PP  .
7    .
8    .SH "PCRE NATIVE API BASIC FUNCTIONS"
9    .rs
10    .sp
11  .SM  .SM
12  .B pcre *pcre_compile(const char *\fIpattern\fP, int \fIoptions\fP,  .B pcre *pcre_compile(const char *\fIpattern\fP, int \fIoptions\fP,
13  .ti +5n  .ti +5n
# Line 25  PCRE - Perl-compatible regular expressio Line 27  PCRE - Perl-compatible regular expressio
27  .ti +5n  .ti +5n
28  .B const char **\fIerrptr\fP);  .B const char **\fIerrptr\fP);
29  .PP  .PP
30    .B void pcre_free_study(pcre_extra *\fIextra\fP);
31    .PP
32  .B int pcre_exec(const pcre *\fIcode\fP, "const pcre_extra *\fIextra\fP,"  .B int pcre_exec(const pcre *\fIcode\fP, "const pcre_extra *\fIextra\fP,"
33  .ti +5n  .ti +5n
34  .B "const char *\fIsubject\fP," int \fIlength\fP, int \fIstartoffset\fP,  .B "const char *\fIsubject\fP," int \fIlength\fP, int \fIstartoffset\fP,
# Line 38  PCRE - Perl-compatible regular expressio Line 42  PCRE - Perl-compatible regular expressio
42  .B int \fIoptions\fP, int *\fIovector\fP, int \fIovecsize\fP,  .B int \fIoptions\fP, int *\fIovector\fP, int \fIovecsize\fP,
43  .ti +5n  .ti +5n
44  .B int *\fIworkspace\fP, int \fIwscount\fP);  .B int *\fIworkspace\fP, int \fIwscount\fP);
45  .PP  .
46    .
47    .SH "PCRE NATIVE API STRING EXTRACTION FUNCTIONS"
48    .rs
49    .sp
50  .B int pcre_copy_named_substring(const pcre *\fIcode\fP,  .B int pcre_copy_named_substring(const pcre *\fIcode\fP,
51  .ti +5n  .ti +5n
52  .B const char *\fIsubject\fP, int *\fIovector\fP,  .B const char *\fIsubject\fP, int *\fIovector\fP,
# Line 82  PCRE - Perl-compatible regular expressio Line 90  PCRE - Perl-compatible regular expressio
90  .B void pcre_free_substring(const char *\fIstringptr\fP);  .B void pcre_free_substring(const char *\fIstringptr\fP);
91  .PP  .PP
92  .B void pcre_free_substring_list(const char **\fIstringptr\fP);  .B void pcre_free_substring_list(const char **\fIstringptr\fP);
93    .
94    .
95    .SH "PCRE NATIVE API AUXILIARY FUNCTIONS"
96    .rs
97    .sp
98    .B pcre_jit_stack *pcre_jit_stack_alloc(int \fIstartsize\fP, int \fImaxsize\fP);
99    .PP
100    .B void pcre_jit_stack_free(pcre_jit_stack *\fIstack\fP);
101    .PP
102    .B void pcre_assign_jit_stack(pcre_extra *\fIextra\fP,
103    .ti +5n
104    .B pcre_jit_callback \fIcallback\fP, void *\fIdata\fP);
105  .PP  .PP
106  .B const unsigned char *pcre_maketables(void);  .B const unsigned char *pcre_maketables(void);
107  .PP  .PP
# Line 89  PCRE - Perl-compatible regular expressio Line 109  PCRE - Perl-compatible regular expressio
109  .ti +5n  .ti +5n
110  .B int \fIwhat\fP, void *\fIwhere\fP);  .B int \fIwhat\fP, void *\fIwhere\fP);
111  .PP  .PP
 .B int pcre_info(const pcre *\fIcode\fP, int *\fIoptptr\fP, int  
 .B *\fIfirstcharptr\fP);  
 .PP  
112  .B int pcre_refcount(pcre *\fIcode\fP, int \fIadjust\fP);  .B int pcre_refcount(pcre *\fIcode\fP, int \fIadjust\fP);
113  .PP  .PP
114  .B int pcre_config(int \fIwhat\fP, void *\fIwhere\fP);  .B int pcre_config(int \fIwhat\fP, void *\fIwhere\fP);
115  .PP  .PP
116  .B char *pcre_version(void);  .B const char *pcre_version(void);
117  .PP  .PP
118    .B int pcre_pattern_to_host_byte_order(pcre *\fIcode\fP,
119    .ti +5n
120    .B pcre_extra *\fIextra\fP, const unsigned char *\fItables\fP);
121    .
122    .
123    .SH "PCRE NATIVE API INDIRECTED FUNCTIONS"
124    .rs
125    .sp
126  .B void *(*pcre_malloc)(size_t);  .B void *(*pcre_malloc)(size_t);
127  .PP  .PP
128  .B void (*pcre_free)(void *);  .B void (*pcre_free)(void *);
# Line 109  PCRE - Perl-compatible regular expressio Line 134  PCRE - Perl-compatible regular expressio
134  .B int (*pcre_callout)(pcre_callout_block *);  .B int (*pcre_callout)(pcre_callout_block *);
135  .  .
136  .  .
137    .SH "PCRE 8-BIT AND 16-BIT LIBRARIES"
138    .rs
139    .sp
140    From release 8.30, PCRE can be compiled as a library for handling 16-bit
141    character strings as well as, or instead of, the original library that handles
142    8-bit character strings. To avoid too much complication, this document
143    describes the 8-bit versions of the functions, with only occasional references
144    to the 16-bit library.
145    .P
146    The 16-bit functions operate in the same way as their 8-bit counterparts; they
147    just use different data types for their arguments and results, and their names
148    start with \fBpcre16_\fP instead of \fBpcre_\fP. For every option that has UTF8
149    in its name (for example, PCRE_UTF8), there is a corresponding 16-bit name with
150    UTF8 replaced by UTF16. This facility is in fact just cosmetic; the 16-bit
151    option names define the same bit values.
152    .P
153    References to bytes and UTF-8 in this document should be read as references to
154    16-bit data quantities and UTF-16 when using the 16-bit library, unless
155    specified otherwise. More details of the specific differences for the 16-bit
156    library are given in the
157    .\" HREF
158    \fBpcre16\fP
159    .\"
160    page.
161    .
162    .
163  .SH "PCRE API OVERVIEW"  .SH "PCRE API OVERVIEW"
164  .rs  .rs
165  .sp  .sp
166  PCRE has its own native API, which is described in this document. There are  PCRE has its own native API, which is described in this document. There are
167  also some wrapper functions that correspond to the POSIX regular expression  also some wrapper functions (for the 8-bit library only) that correspond to the
168  API. These are described in the  POSIX regular expression API, but they do not give access to all the
169    functionality. They are described in the
170  .\" HREF  .\" HREF
171  \fBpcreposix\fP  \fBpcreposix\fP
172  .\"  .\"
173  documentation. Both of these APIs define a set of C function calls. A C++  documentation. Both of these APIs define a set of C function calls. A C++
174  wrapper is distributed with PCRE. It is documented in the  wrapper (again for the 8-bit library only) is also distributed with PCRE. It is
175    documented in the
176  .\" HREF  .\" HREF
177  \fBpcrecpp\fP  \fBpcrecpp\fP
178  .\"  .\"
179  page.  page.
180  .P  .P
181  The native API C function prototypes are defined in the header file  The native API C function prototypes are defined in the header file
182  \fBpcre.h\fP, and on Unix systems the library itself is called \fBlibpcre\fP.  \fBpcre.h\fP, and on Unix-like systems the (8-bit) library itself is called
183  It can normally be accessed by adding \fB-lpcre\fP to the command for linking  \fBlibpcre\fP. It can normally be accessed by adding \fB-lpcre\fP to the
184  an application that uses PCRE. The header file defines the macros PCRE_MAJOR  command for linking an application that uses PCRE. The header file defines the
185  and PCRE_MINOR to contain the major and minor release numbers for the library.  macros PCRE_MAJOR and PCRE_MINOR to contain the major and minor release numbers
186  Applications can use these to include support for different releases of PCRE.  for the library. Applications can use these to include support for different
187    releases of PCRE.
188  .P  .P
189  In a Windows environment, if you want to statically link an application program  In a Windows environment, if you want to statically link an application program
190  against a non-dll \fBpcre.a\fP file, you must define PCRE_STATIC before  against a non-dll \fBpcre.a\fP file, you must define PCRE_STATIC before
# Line 152  documentation, and the Line 206  documentation, and the
206  .\"  .\"
207  documentation describes how to compile and run it.  documentation describes how to compile and run it.
208  .P  .P
209    Just-in-time compiler support is an optional feature of PCRE that can be built
210    in appropriate hardware environments. It greatly speeds up the matching
211    performance of many patterns. Simple programs can easily request that it be
212    used if available, by setting an option that is ignored when it is not
213    relevant. More complicated programs might need to make use of the functions
214    \fBpcre_jit_stack_alloc()\fP, \fBpcre_jit_stack_free()\fP, and
215    \fBpcre_assign_jit_stack()\fP in order to control the JIT code's memory usage.
216    These functions are discussed in the
217    .\" HREF
218    \fBpcrejit\fP
219    .\"
220    documentation.
221    .P
222  A second matching function, \fBpcre_dfa_exec()\fP, which is not  A second matching function, \fBpcre_dfa_exec()\fP, which is not
223  Perl-compatible, is also provided. This uses a different algorithm for the  Perl-compatible, is also provided. This uses a different algorithm for the
224  matching. The alternative algorithm finds all possible matches (at a given  matching. The alternative algorithm finds all possible matches (at a given
# Line 186  specialist use. Most commonly, no specia Line 253  specialist use. Most commonly, no specia
253  internal tables that are generated when PCRE is built are used.  internal tables that are generated when PCRE is built are used.
254  .P  .P
255  The function \fBpcre_fullinfo()\fP is used to find out information about a  The function \fBpcre_fullinfo()\fP is used to find out information about a
256  compiled pattern; \fBpcre_info()\fP is an obsolete version that returns only  compiled pattern. The function \fBpcre_version()\fP returns a pointer to a
257  some of the available information, but is retained for backwards compatibility.  string containing the version of PCRE and its date of release.
 The function \fBpcre_version()\fP returns a pointer to a string containing the  
 version of PCRE and its date of release.  
258  .P  .P
259  The function \fBpcre_refcount()\fP maintains a reference count in a data block  The function \fBpcre_refcount()\fP maintains a reference count in a data block
260  containing a compiled pattern. This is provided for the benefit of  containing a compiled pattern. This is provided for the benefit of
# Line 237  PCRE supports five different conventions Line 302  PCRE supports five different conventions
302  strings: a single CR (carriage return) character, a single LF (linefeed)  strings: a single CR (carriage return) character, a single LF (linefeed)
303  character, the two-character sequence CRLF, any of the three preceding, or any  character, the two-character sequence CRLF, any of the three preceding, or any
304  Unicode newline sequence. The Unicode newline sequences are the three just  Unicode newline sequence. The Unicode newline sequences are the three just
305  mentioned, plus the single characters VT (vertical tab, U+000B), FF (formfeed,  mentioned, plus the single characters VT (vertical tab, U+000B), FF (form feed,
306  U+000C), NEL (next line, U+0085), LS (line separator, U+2028), and PS  U+000C), NEL (next line, U+0085), LS (line separator, U+2028), and PS
307  (paragraph separator, U+2029).  (paragraph separator, U+2029).
308  .P  .P
# Line 282  callout function pointed to by \fBpcre_c Line 347  callout function pointed to by \fBpcre_c
347  .P  .P
348  The compiled form of a regular expression is not altered during matching, so  The compiled form of a regular expression is not altered during matching, so
349  the same compiled pattern can safely be used by several threads at once.  the same compiled pattern can safely be used by several threads at once.
350    .P
351    If the just-in-time optimization feature is being used, it needs separate
352    memory stack areas for each thread. See the
353    .\" HREF
354    \fBpcrejit\fP
355    .\"
356    documentation for more details.
357  .  .
358  .  .
359  .SH "SAVING PRECOMPILED PATTERNS FOR LATER USE"  .SH "SAVING PRECOMPILED PATTERNS FOR LATER USE"
# Line 293  which it was compiled. Details are given Line 365  which it was compiled. Details are given
365  .\" HREF  .\" HREF
366  \fBpcreprecompile\fP  \fBpcreprecompile\fP
367  .\"  .\"
368  documentation. However, compiling a regular expression with one version of PCRE  documentation, which includes a description of the
369  for use with a different version is not guaranteed to work and may cause  \fBpcre_pattern_to_host_byte_order()\fP function. However, compiling a regular
370  crashes.  expression with one version of PCRE for use with a different version is not
371    guaranteed to work and may cause crashes.
372  .  .
373  .  .
374  .SH "CHECKING BUILD-TIME OPTIONS"  .SH "CHECKING BUILD-TIME OPTIONS"
# Line 312  documentation has more details about the Line 385  documentation has more details about the
385  .P  .P
386  The first argument for \fBpcre_config()\fP is an integer, specifying which  The first argument for \fBpcre_config()\fP is an integer, specifying which
387  information is required; the second argument is a pointer to a variable into  information is required; the second argument is a pointer to a variable into
388  which the information is placed. The following information is available:  which the information is placed. The returned value is zero on success, or the
389    negative error code PCRE_ERROR_BADOPTION if the value in the first argument is
390    not recognized. The following information is available:
391  .sp  .sp
392    PCRE_CONFIG_UTF8    PCRE_CONFIG_UTF8
393  .sp  .sp
394  The output is an integer that is set to one if UTF-8 support is available;  The output is an integer that is set to one if UTF-8 support is available;
395  otherwise it is set to zero.  otherwise it is set to zero. If this option is given to the 16-bit version of
396    this function, \fBpcre16_config()\fP, the result is PCRE_ERROR_BADOPTION.
397    .sp
398      PCRE_CONFIG_UTF16
399    .sp
400    The output is an integer that is set to one if UTF-16 support is available;
401    otherwise it is set to zero. This value should normally be given to the 16-bit
402    version of this function, \fBpcre16_config()\fP. If it is given to the 8-bit
403    version of this function, the result is PCRE_ERROR_BADOPTION.
404  .sp  .sp
405    PCRE_CONFIG_UNICODE_PROPERTIES    PCRE_CONFIG_UNICODE_PROPERTIES
406  .sp  .sp
407  The output is an integer that is set to one if support for Unicode character  The output is an integer that is set to one if support for Unicode character
408  properties is available; otherwise it is set to zero.  properties is available; otherwise it is set to zero.
409  .sp  .sp
410      PCRE_CONFIG_JIT
411    .sp
412    The output is an integer that is set to one if support for just-in-time
413    compiling is available; otherwise it is set to zero.
414    .sp
415      PCRE_CONFIG_JITTARGET
416    .sp
417    The output is a pointer to a zero-terminated "const char *" string. If JIT
418    support is available, the string contains the name of the architecture for
419    which the JIT compiler is configured, for example "x86 32bit (little endian +
420    unaligned)". If JIT support is not available, the result is NULL.
421    .sp
422    PCRE_CONFIG_NEWLINE    PCRE_CONFIG_NEWLINE
423  .sp  .sp
424  The output is an integer whose value specifies the default character sequence  The output is an integer whose value specifies the default character sequence
# Line 343  or CRLF. The default can be overridden w Line 438  or CRLF. The default can be overridden w
438    PCRE_CONFIG_LINK_SIZE    PCRE_CONFIG_LINK_SIZE
439  .sp  .sp
440  The output is an integer that contains the number of bytes used for internal  The output is an integer that contains the number of bytes used for internal
441  linkage in compiled regular expressions. The value is 2, 3, or 4. Larger values  linkage in compiled regular expressions. For the 8-bit library, the value can
442  allow larger regular expressions to be compiled, at the expense of slower  be 2, 3, or 4. For the 16-bit library, the value is either 2 or 4 and is still
443  matching. The default value of 2 is sufficient for all but the most massive  a number of bytes. The default value of 2 is sufficient for all but the most
444  patterns, since it allows the compiled pattern to be up to 64K in size.  massive patterns, since it allows the compiled pattern to be up to 64K in size.
445    Larger values allow larger regular expressions to be compiled, at the expense
446    of slower matching.
447  .sp  .sp
448    PCRE_CONFIG_POSIX_MALLOC_THRESHOLD    PCRE_CONFIG_POSIX_MALLOC_THRESHOLD
449  .sp  .sp
# Line 428  within the pattern (see the detailed des Line 525  within the pattern (see the detailed des
525  documentation). For those options that can be different in different parts of  documentation). For those options that can be different in different parts of
526  the pattern, the contents of the \fIoptions\fP argument specifies their  the pattern, the contents of the \fIoptions\fP argument specifies their
527  settings at the start of compilation and execution. The PCRE_ANCHORED,  settings at the start of compilation and execution. The PCRE_ANCHORED,
528  PCRE_BSR_\fIxxx\fP, and PCRE_NEWLINE_\fIxxx\fP options can be set at the time  PCRE_BSR_\fIxxx\fP, PCRE_NEWLINE_\fIxxx\fP, PCRE_NO_UTF8_CHECK, and
529  of matching as well as at compile time.  PCRE_NO_START_OPTIMIZE options can be set at the time of matching as well as at
530    compile time.
531  .P  .P
532  If \fIerrptr\fP is NULL, \fBpcre_compile()\fP returns NULL immediately.  If \fIerrptr\fP is NULL, \fBpcre_compile()\fP returns NULL immediately.
533  Otherwise, if compilation of a pattern fails, \fBpcre_compile()\fP returns  Otherwise, if compilation of a pattern fails, \fBpcre_compile()\fP returns
534  NULL, and sets the variable pointed to by \fIerrptr\fP to point to a textual  NULL, and sets the variable pointed to by \fIerrptr\fP to point to a textual
535  error message. This is a static string that is part of the library. You must  error message. This is a static string that is part of the library. You must
536  not try to free it. The byte offset from the start of the pattern to the  not try to free it. Normally, the offset from the start of the pattern to the
537  character that was being processed when the error was discovered is placed in  byte that was being processed when the error was discovered is placed in the
538  the variable pointed to by \fIerroffset\fP, which must not be NULL. If it is,  variable pointed to by \fIerroffset\fP, which must not be NULL (if it is, an
539  an immediate error is given. Some errors are not detected until checks are  immediate error is given). However, for an invalid UTF-8 string, the offset is
540  carried out when the whole pattern has been scanned; in this case the offset is  that of the first byte of the failing character.
541  set to the end of the pattern.  .P
542    Some errors are not detected until the whole pattern has been scanned; in these
543    cases, the offset passed back is the length of the pattern. Note that the
544    offset is in bytes, not characters, even in UTF-8 mode. It may sometimes point
545    into the middle of a UTF-8 character.
546  .P  .P
547  If \fBpcre_compile2()\fP is used instead of \fBpcre_compile()\fP, and the  If \fBpcre_compile2()\fP is used instead of \fBpcre_compile()\fP, and the
548  \fIerrorcodeptr\fP argument is not NULL, a non-zero error code number is  \fIerrorcodeptr\fP argument is not NULL, a non-zero error code number is
# Line 519  pattern. Line 621  pattern.
621  .sp  .sp
622    PCRE_DOTALL    PCRE_DOTALL
623  .sp  .sp
624  If this bit is set, a dot metacharater in the pattern matches all characters,  If this bit is set, a dot metacharacter in the pattern matches a character of
625  including those that indicate newline. Without it, a dot does not match when  any value, including one that indicates a newline. However, it only ever
626  the current position is at a newline. This option is equivalent to Perl's /s  matches one character, even if newlines are coded as CRLF. Without this option,
627  option, and it can be changed within a pattern by a (?s) option setting. A  a dot does not match when the current position is at a newline. This option is
628  negative class such as [^a] always matches newline characters, independent of  equivalent to Perl's /s option, and it can be changed within a pattern by a
629  the setting of this option.  (?s) option setting. A negative class such as [^a] always matches newline
630    characters, independent of the setting of this option.
631  .sp  .sp
632    PCRE_DUPNAMES    PCRE_DUPNAMES
633  .sp  .sp
# Line 539  documentation. Line 642  documentation.
642  .sp  .sp
643    PCRE_EXTENDED    PCRE_EXTENDED
644  .sp  .sp
645  If this bit is set, whitespace data characters in the pattern are totally  If this bit is set, white space data characters in the pattern are totally
646  ignored except when escaped or inside a character class. Whitespace does not  ignored except when escaped or inside a character class. White space does not
647  include the VT character (code 11). In addition, characters between an  include the VT character (code 11). In addition, characters between an
648  unescaped # outside a character class and the next newline, inclusive, are also  unescaped # outside a character class and the next newline, inclusive, are also
649  ignored. This is equivalent to Perl's /x option, and it can be changed within a  ignored. This is equivalent to Perl's /x option, and it can be changed within a
650  pattern by a (?x) option setting.  pattern by a (?x) option setting.
651  .P  .P
652    Which characters are interpreted as newlines is controlled by the options
653    passed to \fBpcre_compile()\fP or by a special sequence at the start of the
654    pattern, as described in the section entitled
655    .\" HTML <a href="pcrepattern.html#newlines">
656    .\" </a>
657    "Newline conventions"
658    .\"
659    in the \fBpcrepattern\fP documentation. Note that the end of this type of
660    comment is a literal newline sequence in the pattern; escape sequences that
661    happen to represent a newline do not count.
662    .P
663  This option makes it possible to include comments inside complicated patterns.  This option makes it possible to include comments inside complicated patterns.
664  Note, however, that this applies only to data characters. Whitespace characters  Note, however, that this applies only to data characters. White space characters
665  may never appear within special character sequences in a pattern, for example  may never appear within special character sequences in a pattern, for example
666  within the sequence (?( which introduces a conditional subpattern.  within the sequence (?( that introduces a conditional subpattern.
667  .sp  .sp
668    PCRE_EXTRA    PCRE_EXTRA
669  .sp  .sp
# Line 582  character). Thus, the pattern AB]CD beco Line 696  character). Thus, the pattern AB]CD beco
696  string (by default this causes the current matching alternative to fail). A  string (by default this causes the current matching alternative to fail). A
697  pattern such as (\e1)(a) succeeds when this option is set (assuming it can find  pattern such as (\e1)(a) succeeds when this option is set (assuming it can find
698  an "a" in the subject), whereas it fails by default, for Perl compatibility.  an "a" in the subject), whereas it fails by default, for Perl compatibility.
699    .P
700    (3) \eU matches an upper case "U" character; by default \eU causes a compile
701    time error (Perl uses \eU to upper case subsequent characters).
702    .P
703    (4) \eu matches a lower case "u" character unless it is followed by four
704    hexadecimal digits, in which case the hexadecimal number defines the code point
705    to match. By default, \eu causes a compile time error (Perl uses it to upper
706    case the following character).
707    .P
708    (5) \ex matches a lower case "x" character unless it is followed by two
709    hexadecimal digits, in which case the hexadecimal number defines the code point
710    to match. By default, as in Perl, a hexadecimal number is always expected after
711    \ex, but it may have zero, one, or two digits (so, for example, \exz matches a
712    binary zero character followed by z).
713  .sp  .sp
714    PCRE_MULTILINE    PCRE_MULTILINE
715  .sp  .sp
# Line 613  CRLF sequence. Setting PCRE_NEWLINE_ANYC Line 741  CRLF sequence. Setting PCRE_NEWLINE_ANYC
741  preceding sequences should be recognized. Setting PCRE_NEWLINE_ANY specifies  preceding sequences should be recognized. Setting PCRE_NEWLINE_ANY specifies
742  that any Unicode newline sequence should be recognized. The Unicode newline  that any Unicode newline sequence should be recognized. The Unicode newline
743  sequences are the three just mentioned, plus the single characters VT (vertical  sequences are the three just mentioned, plus the single characters VT (vertical
744  tab, U+000B), FF (formfeed, U+000C), NEL (next line, U+0085), LS (line  tab, U+000B), FF (form feed, U+000C), NEL (next line, U+0085), LS (line
745  separator, U+2028), and PS (paragraph separator, U+2029). The last two are  separator, U+2028), and PS (paragraph separator, U+2029). For the 8-bit
746  recognized only in UTF-8 mode.  library, the last two are recognized only in UTF-8 mode.
747  .P  .P
748  The newline setting in the options word uses three bits that are treated  The newline setting in the options word uses three bits that are treated
749  as a number, giving eight possibilities. Currently only six are used (default  as a number, giving eight possibilities. Currently only six are used (default
# Line 624  option, the combination may or may not b Line 752  option, the combination may or may not b
752  PCRE_NEWLINE_CR with PCRE_NEWLINE_LF is equivalent to PCRE_NEWLINE_CRLF, but  PCRE_NEWLINE_CR with PCRE_NEWLINE_LF is equivalent to PCRE_NEWLINE_CRLF, but
753  other combinations may yield unused numbers and cause an error.  other combinations may yield unused numbers and cause an error.
754  .P  .P
755  The only time that a line break is specially recognized when compiling a  The only time that a line break in a pattern is specially recognized when
756  pattern is if PCRE_EXTENDED is set, and an unescaped # outside a character  compiling is when PCRE_EXTENDED is set. CR and LF are white space characters,
757  class is encountered. This indicates a comment that lasts until after the next  and so are ignored in this mode. Also, an unescaped # outside a character class
758  line break sequence. In other circumstances, line break sequences are treated  indicates a comment that lasts until after the next line break sequence. In
759  as literal data, except that in PCRE_EXTENDED mode, both CR and LF are treated  other circumstances, line break sequences in patterns are treated as literal
760  as whitespace characters and are therefore ignored.  data.
761  .P  .P
762  The newline option that is set at compile time becomes the default that is used  The newline option that is set at compile time becomes the default that is used
763  for \fBpcre_exec()\fP and \fBpcre_dfa_exec()\fP, but it can be overridden.  for \fBpcre_exec()\fP and \fBpcre_dfa_exec()\fP, but it can be overridden.
# Line 642  were followed by ?: but named parenthese Line 770  were followed by ?: but named parenthese
770  they acquire numbers in the usual way). There is no equivalent of this option  they acquire numbers in the usual way). There is no equivalent of this option
771  in Perl.  in Perl.
772  .sp  .sp
773      NO_START_OPTIMIZE
774    .sp
775    This is an option that acts at matching time; that is, it is really an option
776    for \fBpcre_exec()\fP or \fBpcre_dfa_exec()\fP. If it is set at compile time,
777    it is remembered with the compiled pattern and assumed at matching time. For
778    details see the discussion of PCRE_NO_START_OPTIMIZE
779    .\" HTML <a href="#execoptions">
780    .\" </a>
781    below.
782    .\"
783    .sp
784    PCRE_UCP    PCRE_UCP
785  .sp  .sp
786  This option changes the way PCRE processes \eb, \ed, \es, \ew, and some of the  This option changes the way PCRE processes \eB, \eb, \eD, \ed, \eS, \es, \eW,
787  POSIX character classes. By default, only ASCII characters are recognized, but  \ew, and some of the POSIX character classes. By default, only ASCII characters
788  if PCRE_UCP is set, Unicode properties are used instead to classify characters.  are recognized, but if PCRE_UCP is set, Unicode properties are used instead to
789  More details are given in the section on  classify characters. More details are given in the section on
790  .\" HTML <a href="pcre.html#genericchartypes">  .\" HTML <a href="pcre.html#genericchartypes">
791  .\" </a>  .\" </a>
792  generic character types  generic character types
# Line 669  with Perl. It can also be set by a (?U) Line 808  with Perl. It can also be set by a (?U)
808    PCRE_UTF8    PCRE_UTF8
809  .sp  .sp
810  This option causes PCRE to regard both the pattern and the subject as strings  This option causes PCRE to regard both the pattern and the subject as strings
811  of UTF-8 characters instead of single-byte character strings. However, it is  of UTF-8 characters instead of single-byte strings. However, it is available
812  available only when PCRE is built to include UTF-8 support. If not, the use  only when PCRE is built to include UTF support. If not, the use of this option
813  of this option provokes an error. Details of how this option changes the  provokes an error. Details of how this option changes the behaviour of PCRE are
814  behaviour of PCRE are given in the  given in the
 .\" HTML <a href="pcre.html#utf8support">  
 .\" </a>  
 section on UTF-8 support  
 .\"  
 in the main  
815  .\" HREF  .\" HREF
816  \fBpcre\fP  \fBpcreunicode\fP
817  .\"  .\"
818  page.  page.
819  .sp  .sp
820    PCRE_NO_UTF8_CHECK    PCRE_NO_UTF8_CHECK
821  .sp  .sp
822  When PCRE_UTF8 is set, the validity of the pattern as a UTF-8 string is  When PCRE_UTF8 is set, the validity of the pattern as a UTF-8
823  automatically checked. There is a discussion about the  string is automatically checked. There is a discussion about the
824  .\" HTML <a href="pcre.html#utf8strings">  .\" HTML <a href="pcreunicode.html#utf8strings">
825  .\" </a>  .\" </a>
826  validity of UTF-8 strings  validity of UTF-8 strings
827  .\"  .\"
828  in the main  in the
829  .\" HREF  .\" HREF
830  \fBpcre\fP  \fBpcreunicode\fP
831  .\"  .\"
832  page. If an invalid UTF-8 sequence of bytes is found, \fBpcre_compile()\fP  page. If an invalid UTF-8 sequence is found, \fBpcre_compile()\fP returns an
833  returns an error. If you already know that your pattern is valid, and you want  error. If you already know that your pattern is valid, and you want to skip
834  to skip this check for performance reasons, you can set the PCRE_NO_UTF8_CHECK  this check for performance reasons, you can set the PCRE_NO_UTF8_CHECK option.
835  option. When it is set, the effect of passing an invalid UTF-8 string as a  When it is set, the effect of passing an invalid UTF-8 string as a pattern is
836  pattern is undefined. It may cause your program to crash. Note that this option  undefined. It may cause your program to crash. Note that this option can also
837  can also be passed to \fBpcre_exec()\fP and \fBpcre_dfa_exec()\fP, to suppress  be passed to \fBpcre_exec()\fP and \fBpcre_dfa_exec()\fP, to suppress the
838  the UTF-8 validity checking of subject strings.  validity checking of subject strings.
839  .  .
840  .  .
841  .SH "COMPILATION ERROR CODES"  .SH "COMPILATION ERROR CODES"
# Line 709  the UTF-8 validity checking of subject s Line 843  the UTF-8 validity checking of subject s
843  .sp  .sp
844  The following table lists the error codes than may be returned by  The following table lists the error codes than may be returned by
845  \fBpcre_compile2()\fP, along with the error messages that may be returned by  \fBpcre_compile2()\fP, along with the error messages that may be returned by
846  both compiling functions. As PCRE has developed, some error codes have fallen  both compiling functions. Note that error messages are always 8-bit ASCII
847  out of use. To avoid confusion, they have not been re-used.  strings, even in 16-bit mode. As PCRE has developed, some error codes have
848    fallen out of use. To avoid confusion, they have not been re-used.
849  .sp  .sp
850     0  no error     0  no error
851     1  \e at end of pattern     1  \e at end of pattern
# Line 744  out of use. To avoid confusion, they hav Line 879  out of use. To avoid confusion, they hav
879    29  (?R or (?[+-]digits must be followed by )    29  (?R or (?[+-]digits must be followed by )
880    30  unknown POSIX class name    30  unknown POSIX class name
881    31  POSIX collating elements are not supported    31  POSIX collating elements are not supported
882    32  this version of PCRE is not compiled with PCRE_UTF8 support    32  this version of PCRE is compiled without UTF support
883    33  [this code is not in use]    33  [this code is not in use]
884    34  character value in \ex{...} sequence is too large    34  character value in \ex{...} sequence is too large
885    35  invalid condition (?(0)    35  invalid condition (?(0)
886    36  \eC not allowed in lookbehind assertion    36  \eC not allowed in lookbehind assertion
887    37  PCRE does not support \eL, \el, \eN, \eU, or \eu    37  PCRE does not support \eL, \el, \eN{name}, \eU, or \eu
888    38  number after (?C is > 255    38  number after (?C is > 255
889    39  closing ) for (?C expected    39  closing ) for (?C expected
890    40  recursive call could loop indefinitely    40  recursive call could loop indefinitely
891    41  unrecognized character after (?P    41  unrecognized character after (?P
892    42  syntax error in subpattern name (missing terminator)    42  syntax error in subpattern name (missing terminator)
893    43  two named subpatterns have the same name    43  two named subpatterns have the same name
894    44  invalid UTF-8 string    44  invalid UTF-8 string (specifically UTF-8)
895    45  support for \eP, \ep, and \eX has not been compiled    45  support for \eP, \ep, and \eX has not been compiled
896    46  malformed \eP or \ep sequence    46  malformed \eP or \ep sequence
897    47  unknown property name after \eP or \ep    47  unknown property name after \eP or \ep
898    48  subpattern name is too long (maximum 32 characters)    48  subpattern name is too long (maximum 32 characters)
899    49  too many named subpatterns (maximum 10000)    49  too many named subpatterns (maximum 10000)
900    50  [this code is not in use]    50  [this code is not in use]
901    51  octal value is greater than \e377 (not in UTF-8 mode)    51  octal value is greater than \e377 in 8-bit non-UTF-8 mode
902    52  internal error: overran compiling workspace    52  internal error: overran compiling workspace
903    53  internal error: previously-checked referenced subpattern    53  internal error: previously-checked referenced subpattern
904          not found          not found
# Line 782  out of use. To avoid confusion, they hav Line 917  out of use. To avoid confusion, they hav
917    65  different names for subpatterns of the same number are    65  different names for subpatterns of the same number are
918          not allowed          not allowed
919    66  (*MARK) must have an argument    66  (*MARK) must have an argument
920    67  this version of PCRE is not compiled with PCRE_UCP support    67  this version of PCRE is not compiled with Unicode property
921            support
922      68  \ec must be followed by an ASCII character
923      69  \ek is not followed by a braced, angle-bracketed, or quoted name
924      70  internal error: unknown opcode in find_fixedlength()
925      71  \eN is not supported in a class
926      72  too many forward references
927      73  disallowed Unicode code point (>= 0xd800 && <= 0xdfff)
928      74  invalid UTF-16 string (specifically UTF-16)
929      75  name is too long in (*MARK), (*PRUNE), (*SKIP), or (*THEN)
930      76  character value in \eu.... sequence is too large
931  .sp  .sp
932  The numbers 32 and 10000 in errors 48 and 49 are defaults; different values may  The numbers 32 and 10000 in errors 48 and 49 are defaults; different values may
933  be used if the limits were changed when PCRE was built.  be used if the limits were changed when PCRE was built.
934  .  .
935  .  .
936    .\" HTML <a name="studyingapattern"></a>
937  .SH "STUDYING A PATTERN"  .SH "STUDYING A PATTERN"
938  .rs  .rs
939  .sp  .sp
# Line 814  below Line 960  below
960  in the section on matching a pattern.  in the section on matching a pattern.
961  .P  .P
962  If studying the pattern does not produce any useful information,  If studying the pattern does not produce any useful information,
963  \fBpcre_study()\fP returns NULL. In that circumstance, if the calling program  \fBpcre_study()\fP returns NULL by default. In that circumstance, if the
964  wants to pass any of the other fields to \fBpcre_exec()\fP or  calling program wants to pass any of the other fields to \fBpcre_exec()\fP or
965  \fBpcre_dfa_exec()\fP, it must set up its own \fBpcre_extra\fP block.  \fBpcre_dfa_exec()\fP, it must set up its own \fBpcre_extra\fP block. However,
966  .P  if \fBpcre_study()\fP is called with the PCRE_STUDY_EXTRA_NEEDED option, it
967  The second argument of \fBpcre_study()\fP contains option bits. At present, no  returns a \fBpcre_extra\fP block even if studying did not find any additional
968  options are defined, and this argument should always be zero.  information. It may still return NULL, however, if an error occurs in
969    \fBpcre_study()\fP.
970    .P
971    The second argument of \fBpcre_study()\fP contains option bits. There are three
972    further options in addition to PCRE_STUDY_EXTRA_NEEDED:
973    .sp
974      PCRE_STUDY_JIT_COMPILE
975      PCRE_STUDY_JIT_PARTIAL_HARD_COMPILE
976      PCRE_STUDY_JIT_PARTIAL_SOFT_COMPILE
977    .sp
978    If any of these are set, and the just-in-time compiler is available, the
979    pattern is further compiled into machine code that executes much faster than
980    the \fBpcre_exec()\fP interpretive matching function. If the just-in-time
981    compiler is not available, these options are ignored. All undefined bits in the
982    \fIoptions\fP argument must be zero.
983    .P
984    JIT compilation is a heavyweight optimization. It can take some time for
985    patterns to be analyzed, and for one-off matches and simple patterns the
986    benefit of faster execution might be offset by a much slower study time.
987    Not all patterns can be optimized by the JIT compiler. For those that cannot be
988    handled, matching automatically falls back to the \fBpcre_exec()\fP
989    interpreter. For more details, see the
990    .\" HREF
991    \fBpcrejit\fP
992    .\"
993    documentation.
994  .P  .P
995  The third argument for \fBpcre_study()\fP is a pointer for an error message. If  The third argument for \fBpcre_study()\fP is a pointer for an error message. If
996  studying succeeds (even if no data is returned), the variable it points to is  studying succeeds (even if no data is returned), the variable it points to is
# Line 828  static string that is part of the librar Line 999  static string that is part of the librar
999  should test the error pointer for NULL after calling \fBpcre_study()\fP, to be  should test the error pointer for NULL after calling \fBpcre_study()\fP, to be
1000  sure that it has run successfully.  sure that it has run successfully.
1001  .P  .P
1002  This is a typical call to \fBpcre_study\fP():  When you are finished with a pattern, you can free the memory used for the
1003    study data by calling \fBpcre_free_study()\fP. This function was added to the
1004    API for release 8.20. For earlier versions, the memory could be freed with
1005    \fBpcre_free()\fP, just like the pattern itself. This will still work in cases
1006    where JIT optimization is not used, but it is advisable to change to the new
1007    function when convenient.
1008    .P
1009    This is a typical way in which \fBpcre_study\fP() is used (except that in a
1010    real application there should be tests for errors):
1011  .sp  .sp
1012    pcre_extra *pe;    int rc;
1013    pe = pcre_study(    pcre *re;
1014      pcre_extra *sd;
1015      re = pcre_compile("pattern", 0, &error, &erroroffset, NULL);
1016      sd = pcre_study(
1017      re,             /* result of pcre_compile() */      re,             /* result of pcre_compile() */
1018      0,              /* no options exist */      0,              /* no options */
1019      &error);        /* set to NULL or points to a message */      &error);        /* set to NULL or points to a message */
1020      rc = pcre_exec(   /* see below for details of pcre_exec() options */
1021        re, sd, "subject", 7, 0, 0, ovector, 30);
1022      ...
1023      pcre_free_study(sd);
1024      pcre_free(re);
1025  .sp  .sp
1026  Studying a pattern does two things: first, a lower bound for the length of  Studying a pattern does two things: first, a lower bound for the length of
1027  subject string that is needed to match the pattern is computed. This does not  subject string that is needed to match the pattern is computed. This does not
1028  mean that there are any strings of that length that match, but it does  mean that there are any strings of that length that match, but it does
1029  guarantee that no shorter strings match. The value is used by  guarantee that no shorter strings match. The value is used to avoid wasting
1030  \fBpcre_exec()\fP and \fBpcre_dfa_exec()\fP to avoid wasting time by trying to  time by trying to match strings that are shorter than the lower bound. You can
1031  match strings that are shorter than the lower bound. You can find out the value  find out the value in a calling program via the \fBpcre_fullinfo()\fP function.
 in a calling program via the \fBpcre_fullinfo()\fP function.  
1032  .P  .P
1033  Studying a pattern is also useful for non-anchored patterns that do not have a  Studying a pattern is also useful for non-anchored patterns that do not have a
1034  single fixed starting character. A bitmap of possible starting bytes is  single fixed starting character. A bitmap of possible starting bytes is
1035  created. This speeds up finding a position in the subject at which to start  created. This speeds up finding a position in the subject at which to start
1036  matching.  matching. (In 16-bit mode, the bitmap is used for 16-bit values less than 256.)
1037  .P  .P
1038  The two optimizations just described can be disabled by setting the  These two optimizations apply to both \fBpcre_exec()\fP and
1039  PCRE_NO_START_OPTIMIZE option when calling \fBpcre_exec()\fP or  \fBpcre_dfa_exec()\fP, and the information is also used by the JIT compiler.
1040  \fBpcre_dfa_exec()\fP. You might want to do this if your pattern contains  The optimizations can be disabled by setting the PCRE_NO_START_OPTIMIZE option
1041  callouts, or make use of (*MARK), and you make use of these in cases where  when calling \fBpcre_exec()\fP or \fBpcre_dfa_exec()\fP, but if this is done,
1042  matching fails. See the discussion of PCRE_NO_START_OPTIMIZE  JIT execution is also disabled. You might want to do this if your pattern
1043    contains callouts or (*MARK) and you want to make use of these facilities in
1044    cases where matching fails. See the discussion of PCRE_NO_START_OPTIMIZE
1045  .\" HTML <a href="#execoptions">  .\" HTML <a href="#execoptions">
1046  .\" </a>  .\" </a>
1047  below.  below.
# Line 866  below. Line 1054  below.
1054  .sp  .sp
1055  PCRE handles caseless matching, and determines whether characters are letters,  PCRE handles caseless matching, and determines whether characters are letters,
1056  digits, or whatever, by reference to a set of tables, indexed by character  digits, or whatever, by reference to a set of tables, indexed by character
1057  value. When running in UTF-8 mode, this applies only to characters with codes  value. When running in UTF-8 mode, this applies only to characters
1058  less than 128. By default, higher-valued codes never match escapes such as \ew  with codes less than 128. By default, higher-valued codes never match escapes
1059  or \ed, but they can be tested with \ep if PCRE is built with Unicode character  such as \ew or \ed, but they can be tested with \ep if PCRE is built with
1060  property support. Alternatively, the PCRE_UCP option can be set at compile  Unicode character property support. Alternatively, the PCRE_UCP option can be
1061  time; this causes \ew and friends to use Unicode property support instead of  set at compile time; this causes \ew and friends to use Unicode property
1062  built-in tables. The use of locales with Unicode is discouraged. If you are  support instead of built-in tables. The use of locales with Unicode is
1063  handling characters with codes greater than 128, you should either use UTF-8  discouraged. If you are handling characters with codes greater than 128, you
1064  and Unicode, or use locales, but not try to mix the two.  should either use UTF-8 and Unicode, or use locales, but not try to mix the
1065    two.
1066  .P  .P
1067  PCRE contains an internal set of tables that are used when the final argument  PCRE contains an internal set of tables that are used when the final argument
1068  of \fBpcre_compile()\fP is NULL. These are sufficient for many applications.  of \fBpcre_compile()\fP is NULL. These are sufficient for many applications.
# Line 918  one in which it was compiled. Passing ta Line 1107  one in which it was compiled. Passing ta
1107  below in the section on matching a pattern.  below in the section on matching a pattern.
1108  .  .
1109  .  .
1110    .\" HTML <a name="infoaboutpattern"></a>
1111  .SH "INFORMATION ABOUT A PATTERN"  .SH "INFORMATION ABOUT A PATTERN"
1112  .rs  .rs
1113  .sp  .sp
# Line 926  below in the section on matching a patte Line 1116  below in the section on matching a patte
1116  .B int \fIwhat\fP, void *\fIwhere\fP);  .B int \fIwhat\fP, void *\fIwhere\fP);
1117  .PP  .PP
1118  The \fBpcre_fullinfo()\fP function returns information about a compiled  The \fBpcre_fullinfo()\fP function returns information about a compiled
1119  pattern. It replaces the obsolete \fBpcre_info()\fP function, which is  pattern. It replaces the \fBpcre_info()\fP function, which was removed from the
1120  nevertheless retained for backwards compability (and is documented below).  library at version 8.30, after more than 10 years of obsolescence.
1121  .P  .P
1122  The first argument for \fBpcre_fullinfo()\fP is a pointer to the compiled  The first argument for \fBpcre_fullinfo()\fP is a pointer to the compiled
1123  pattern. The second argument is the result of \fBpcre_study()\fP, or NULL if  pattern. The second argument is the result of \fBpcre_study()\fP, or NULL if
# Line 936  information is required, and the fourth Line 1126  information is required, and the fourth
1126  to receive the data. The yield of the function is zero for success, or one of  to receive the data. The yield of the function is zero for success, or one of
1127  the following negative numbers:  the following negative numbers:
1128  .sp  .sp
1129    PCRE_ERROR_NULL       the argument \fIcode\fP was NULL    PCRE_ERROR_NULL           the argument \fIcode\fP was NULL
1130                          the argument \fIwhere\fP was NULL                              the argument \fIwhere\fP was NULL
1131    PCRE_ERROR_BADMAGIC   the "magic number" was not found    PCRE_ERROR_BADMAGIC       the "magic number" was not found
1132    PCRE_ERROR_BADOPTION  the value of \fIwhat\fP was invalid    PCRE_ERROR_BADENDIANNESS  the pattern was compiled with different
1133                                endianness
1134      PCRE_ERROR_BADOPTION      the value of \fIwhat\fP was invalid
1135  .sp  .sp
1136  The "magic number" is placed at the start of each compiled pattern as an simple  The "magic number" is placed at the start of each compiled pattern as an simple
1137  check against passing an arbitrary memory pointer. Here is a typical call of  check against passing an arbitrary memory pointer. The endianness error can
1138  \fBpcre_fullinfo()\fP, to obtain the length of the compiled pattern:  occur if a compiled pattern is saved and reloaded on a different host. Here is
1139    a typical call of \fBpcre_fullinfo()\fP, to obtain the length of the compiled
1140    pattern:
1141  .sp  .sp
1142    int rc;    int rc;
1143    size_t length;    size_t length;
1144    rc = pcre_fullinfo(    rc = pcre_fullinfo(
1145      re,               /* result of pcre_compile() */      re,               /* result of pcre_compile() */
1146      pe,               /* result of pcre_study(), or NULL */      sd,               /* result of pcre_study(), or NULL */
1147      PCRE_INFO_SIZE,   /* what is required */      PCRE_INFO_SIZE,   /* what is required */
1148      &length);         /* where to put the data */      &length);         /* where to put the data */
1149  .sp  .sp
# Line 977  a NULL table pointer. Line 1171  a NULL table pointer.
1171  .sp  .sp
1172    PCRE_INFO_FIRSTBYTE    PCRE_INFO_FIRSTBYTE
1173  .sp  .sp
1174  Return information about the first byte of any matched string, for a  Return information about the first data unit of any matched string, for a
1175  non-anchored pattern. The fourth argument should point to an \fBint\fP  non-anchored pattern. (The name of this option refers to the 8-bit library,
1176  variable. (This option used to be called PCRE_INFO_FIRSTCHAR; the old name is  where data units are bytes.) The fourth argument should point to an \fBint\fP
1177  still recognized for backwards compatibility.)  variable.
1178    .P
1179    If there is a fixed first value, for example, the letter "c" from a pattern
1180    such as (cat|cow|coyote), its value is returned. In the 8-bit library, the
1181    value is always less than 256; in the 16-bit library the value can be up to
1182    0xffff.
1183  .P  .P
1184  If there is a fixed first byte, for example, from a pattern such as  If there is no fixed first value, and if either
 (cat|cow|coyote), its value is returned. Otherwise, if either  
1185  .sp  .sp
1186  (a) the pattern was compiled with the PCRE_MULTILINE option, and every branch  (a) the pattern was compiled with the PCRE_MULTILINE option, and every branch
1187  starts with "^", or  starts with "^", or
# Line 998  returned. For anchored patterns, -2 is r Line 1196  returned. For anchored patterns, -2 is r
1196    PCRE_INFO_FIRSTTABLE    PCRE_INFO_FIRSTTABLE
1197  .sp  .sp
1198  If the pattern was studied, and this resulted in the construction of a 256-bit  If the pattern was studied, and this resulted in the construction of a 256-bit
1199  table indicating a fixed set of bytes for the first byte in any matching  table indicating a fixed set of values for the first data unit in any matching
1200  string, a pointer to the table is returned. Otherwise NULL is returned. The  string, a pointer to the table is returned. Otherwise NULL is returned. The
1201  fourth argument should point to an \fBunsigned char *\fP variable.  fourth argument should point to an \fBunsigned char *\fP variable.
1202  .sp  .sp
# Line 1014  Return 1 if the (?J) or (?-J) option set Line 1212  Return 1 if the (?J) or (?-J) option set
1212  0. The fourth argument should point to an \fBint\fP variable. (?J) and  0. The fourth argument should point to an \fBint\fP variable. (?J) and
1213  (?-J) set and unset the local PCRE_DUPNAMES option, respectively.  (?-J) set and unset the local PCRE_DUPNAMES option, respectively.
1214  .sp  .sp
1215      PCRE_INFO_JIT
1216    .sp
1217    Return 1 if the pattern was studied with one of the JIT options, and
1218    just-in-time compiling was successful. The fourth argument should point to an
1219    \fBint\fP variable. A return value of 0 means that JIT support is not available
1220    in this version of PCRE, or that the pattern was not studied with a JIT option,
1221    or that the JIT compiler could not handle this particular pattern. See the
1222    .\" HREF
1223    \fBpcrejit\fP
1224    .\"
1225    documentation for details of what can and cannot be handled.
1226    .sp
1227      PCRE_INFO_JITSIZE
1228    .sp
1229    If the pattern was successfully studied with a JIT option, return the size of
1230    the JIT compiled code, otherwise return zero. The fourth argument should point
1231    to a \fBsize_t\fP variable.
1232    .sp
1233    PCRE_INFO_LASTLITERAL    PCRE_INFO_LASTLITERAL
1234  .sp  .sp
1235  Return the value of the rightmost literal byte that must exist in any matched  Return the value of the rightmost literal data unit that must exist in any
1236  string, other than at its start, if such a byte has been recorded. The fourth  matched string, other than at its start, if such a value has been recorded. The
1237  argument should point to an \fBint\fP variable. If there is no such byte, -1 is  fourth argument should point to an \fBint\fP variable. If there is no such
1238  returned. For anchored patterns, a last literal byte is recorded only if it  value, -1 is returned. For anchored patterns, a last literal value is recorded
1239  follows something of variable length. For example, for the pattern  only if it follows something of variable length. For example, for the pattern
1240  /^a\ed+z\ed+/ the returned value is "z", but for /^a\edz\ed/ the returned value  /^a\ed+z\ed+/ the returned value is "z", but for /^a\edz\ed/ the returned value
1241  is -1.  is -1.
1242  .sp  .sp
1243      PCRE_INFO_MAXLOOKBEHIND
1244    .sp
1245    Return the number of characters (NB not bytes) in the longest lookbehind
1246    assertion in the pattern. Note that the simple assertions \eb and \eB require a
1247    one-character lookbehind. This information is useful when doing multi-segment
1248    matching using the partial matching facilities.
1249    .sp
1250    PCRE_INFO_MINLENGTH    PCRE_INFO_MINLENGTH
1251  .sp  .sp
1252  If the pattern was studied and a minimum length for matching subject strings  If the pattern was studied and a minimum length for matching subject strings
1253  was computed, its value is returned. Otherwise the returned value is -1. The  was computed, its value is returned. Otherwise the returned value is -1. The
1254  value is a number of characters, not bytes (this may be relevant in UTF-8  value is a number of characters, which in UTF-8 mode may be different from the
1255  mode). The fourth argument should point to an \fBint\fP variable. A  number of bytes. The fourth argument should point to an \fBint\fP variable. A
1256  non-negative value is a lower bound to the length of any matching string. There  non-negative value is a lower bound to the length of any matching string. There
1257  may not be any strings of that length that do actually match, but every string  may not be any strings of that length that do actually match, but every string
1258  that does match is at least that long.  that does match is at least that long.
# Line 1052  The map consists of a number of fixed-si Line 1275  The map consists of a number of fixed-si
1275  the number of entries, and PCRE_INFO_NAMEENTRYSIZE gives the size of each  the number of entries, and PCRE_INFO_NAMEENTRYSIZE gives the size of each
1276  entry; both of these return an \fBint\fP value. The entry size depends on the  entry; both of these return an \fBint\fP value. The entry size depends on the
1277  length of the longest name. PCRE_INFO_NAMETABLE returns a pointer to the first  length of the longest name. PCRE_INFO_NAMETABLE returns a pointer to the first
1278  entry of the table (a pointer to \fBchar\fP). The first two bytes of each entry  entry of the table. This is a pointer to \fBchar\fP in the 8-bit library, where
1279  are the number of the capturing parenthesis, most significant byte first. The  the first two bytes of each entry are the number of the capturing parenthesis,
1280  rest of the entry is the corresponding name, zero terminated.  most significant byte first. In the 16-bit library, the pointer points to
1281    16-bit data units, the first of which contains the parenthesis number. The rest
1282    of the entry is the corresponding name, zero terminated.
1283  .P  .P
1284  The names are in alphabetical order. Duplicate names may appear if (?| is used  The names are in alphabetical order. Duplicate names may appear if (?| is used
1285  to create multiple groups with the same number, as described in the  to create multiple groups with the same number, as described in the
# Line 1073  table in the order in which they were fo Line 1298  table in the order in which they were fo
1298  necessarily the case because later subpatterns may have lower numbers.  necessarily the case because later subpatterns may have lower numbers.
1299  .P  .P
1300  As a simple example of the name/number table, consider the following pattern  As a simple example of the name/number table, consider the following pattern
1301  (assume PCRE_EXTENDED is set, so white space - including newlines - is  after compilation by the 8-bit library (assume PCRE_EXTENDED is set, so white
1302  ignored):  space - including newlines - is ignored):
1303  .sp  .sp
1304  .\" JOIN  .\" JOIN
1305    (?<date> (?<year>(\ed\ed)?\ed\ed) -    (?<date> (?<year>(\ed\ed)?\ed\ed) -
# Line 1129  For such patterns, the PCRE_ANCHORED bit Line 1354  For such patterns, the PCRE_ANCHORED bit
1354  .sp  .sp
1355    PCRE_INFO_SIZE    PCRE_INFO_SIZE
1356  .sp  .sp
1357  Return the size of the compiled pattern, that is, the value that was passed as  Return the size of the compiled pattern in bytes (for both libraries). The
1358  the argument to \fBpcre_malloc()\fP when PCRE was getting memory in which to  fourth argument should point to a \fBsize_t\fP variable. This value does not
1359  place the compiled data. The fourth argument should point to a \fBsize_t\fP  include the size of the \fBpcre\fP structure that is returned by
1360  variable.  \fBpcre_compile()\fP. The value that is passed as the argument to
1361    \fBpcre_malloc()\fP when \fBpcre_compile()\fP is getting memory in which to
1362    place the compiled data is the value returned by this option plus the size of
1363    the \fBpcre\fP structure. Studying a compiled pattern, with or without JIT,
1364    does not alter the value returned by this option.
1365  .sp  .sp
1366    PCRE_INFO_STUDYSIZE    PCRE_INFO_STUDYSIZE
1367  .sp  .sp
1368  Return the size of the data block pointed to by the \fIstudy_data\fP field in  Return the size in bytes of the data block pointed to by the \fIstudy_data\fP
1369  a \fBpcre_extra\fP block. That is, it is the value that was passed to  field in a \fBpcre_extra\fP block. If \fBpcre_extra\fP is NULL, or there is no
 \fBpcre_malloc()\fP when PCRE was getting memory into which to place the data  
 created by \fBpcre_study()\fP. If \fBpcre_extra\fP is NULL, or there is no  
1370  study data, zero is returned. The fourth argument should point to a  study data, zero is returned. The fourth argument should point to a
1371  \fBsize_t\fP variable.  \fBsize_t\fP variable. The \fIstudy_data\fP field is set by \fBpcre_study()\fP
1372  .  to record information that will speed up matching (see the section entitled
1373  .  .\" HTML <a href="#studyingapattern">
1374  .SH "OBSOLETE INFO FUNCTION"  .\" </a>
1375  .rs  "Studying a pattern"
1376  .sp  .\"
1377  .B int pcre_info(const pcre *\fIcode\fP, int *\fIoptptr\fP, int  above). The format of the \fIstudy_data\fP block is private, but its length
1378  .B *\fIfirstcharptr\fP);  is made available via this option so that it can be saved and restored (see the
1379  .PP  .\" HREF
1380  The \fBpcre_info()\fP function is now obsolete because its interface is too  \fBpcreprecompile\fP
1381  restrictive to return all the available data about a compiled pattern. New  .\"
1382  programs should use \fBpcre_fullinfo()\fP instead. The yield of  documentation for details).
 \fBpcre_info()\fP is the number of capturing subpatterns, or one of the  
 following negative numbers:  
 .sp  
   PCRE_ERROR_NULL       the argument \fIcode\fP was NULL  
   PCRE_ERROR_BADMAGIC   the "magic number" was not found  
 .sp  
 If the \fIoptptr\fP 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  
 If the pattern is not anchored and the \fIfirstcharptr\fP argument is not NULL,  
 it is used to pass back information about the first character of any matched  
 string (see PCRE_INFO_FIRSTBYTE above).  
1383  .  .
1384  .  .
1385  .SH "REFERENCE COUNTS"  .SH "REFERENCE COUNTS"
# Line 1203  is different. (This seems a highly unlik Line 1417  is different. (This seems a highly unlik
1417  The function \fBpcre_exec()\fP is called to match a subject string against a  The function \fBpcre_exec()\fP is called to match a subject string against a
1418  compiled pattern, which is passed in the \fIcode\fP argument. If the  compiled pattern, which is passed in the \fIcode\fP argument. If the
1419  pattern was studied, the result of the study should be passed in the  pattern was studied, the result of the study should be passed in the
1420  \fIextra\fP argument. This function is the main matching facility of the  \fIextra\fP argument. You can call \fBpcre_exec()\fP with the same \fIcode\fP
1421  library, and it operates in a Perl-like manner. For specialist use there is  and \fIextra\fP arguments as many times as you like, in order to match
1422  also an alternative matching function, which is described  different subject strings with the same pattern.
1423    .P
1424    This function is the main matching facility of the library, and it operates in
1425    a Perl-like manner. For specialist use there is also an alternative matching
1426    function, which is described
1427  .\" HTML <a href="#dfamatch">  .\" HTML <a href="#dfamatch">
1428  .\" </a>  .\" </a>
1429  below  below
# Line 1236  Here is an example of a simple call to \ Line 1454  Here is an example of a simple call to \
1454      ovector,        /* vector of integers for substring information */      ovector,        /* vector of integers for substring information */
1455      30);            /* number of elements (NOT size in bytes) */      30);            /* number of elements (NOT size in bytes) */
1456  .  .
1457    .
1458  .\" HTML <a name="extradata"></a>  .\" HTML <a name="extradata"></a>
1459  .SS "Extra data for \fBpcre_exec()\fR"  .SS "Extra data for \fBpcre_exec()\fR"
1460  .rs  .rs
# Line 1248  fields (not necessarily in this order): Line 1467  fields (not necessarily in this order):
1467  .sp  .sp
1468    unsigned long int \fIflags\fP;    unsigned long int \fIflags\fP;
1469    void *\fIstudy_data\fP;    void *\fIstudy_data\fP;
1470      void *\fIexecutable_jit\fP;
1471    unsigned long int \fImatch_limit\fP;    unsigned long int \fImatch_limit\fP;
1472    unsigned long int \fImatch_limit_recursion\fP;    unsigned long int \fImatch_limit_recursion\fP;
1473    void *\fIcallout_data\fP;    void *\fIcallout_data\fP;
1474    const unsigned char *\fItables\fP;    const unsigned char *\fItables\fP;
1475    unsigned char **\fImark\fP;    unsigned char **\fImark\fP;
1476  .sp  .sp
1477  The \fIflags\fP field is a bitmap that specifies which of the other fields  In the 16-bit version of this structure, the \fImark\fP field has type
1478  are set. The flag bits are:  "PCRE_UCHAR16 **".
1479    .P
1480    The \fIflags\fP field is used to specify which of the other fields are set. The
1481    flag bits are:
1482  .sp  .sp
1483    PCRE_EXTRA_STUDY_DATA    PCRE_EXTRA_CALLOUT_DATA
1484      PCRE_EXTRA_EXECUTABLE_JIT
1485      PCRE_EXTRA_MARK
1486    PCRE_EXTRA_MATCH_LIMIT    PCRE_EXTRA_MATCH_LIMIT
1487    PCRE_EXTRA_MATCH_LIMIT_RECURSION    PCRE_EXTRA_MATCH_LIMIT_RECURSION
1488    PCRE_EXTRA_CALLOUT_DATA    PCRE_EXTRA_STUDY_DATA
1489    PCRE_EXTRA_TABLES    PCRE_EXTRA_TABLES
   PCRE_EXTRA_MARK  
1490  .sp  .sp
1491  Other flag bits should be set to zero. The \fIstudy_data\fP field is set in the  Other flag bits should be set to zero. The \fIstudy_data\fP field and sometimes
1492  \fBpcre_extra\fP block that is returned by \fBpcre_study()\fP, together with  the \fIexecutable_jit\fP field are set in the \fBpcre_extra\fP block that is
1493  the appropriate flag bit. You should not set this yourself, but you may add to  returned by \fBpcre_study()\fP, together with the appropriate flag bits. You
1494  the block by setting the other fields and their corresponding flag bits.  should not set these yourself, but you may add to the block by setting other
1495    fields and their corresponding flag bits.
1496  .P  .P
1497  The \fImatch_limit\fP field provides a means of preventing PCRE from using up a  The \fImatch_limit\fP field provides a means of preventing PCRE from using up a
1498  vast amount of resources when running patterns that are not going to match,  vast amount of resources when running patterns that are not going to match,
1499  but which have a very large number of possibilities in their search trees. The  but which have a very large number of possibilities in their search trees. The
1500  classic example is a pattern that uses nested unlimited repeats.  classic example is a pattern that uses nested unlimited repeats.
1501  .P  .P
1502  Internally, PCRE uses a function called \fBmatch()\fP which it calls repeatedly  Internally, \fBpcre_exec()\fP uses a function called \fBmatch()\fP, which it
1503  (sometimes recursively). The limit set by \fImatch_limit\fP is imposed on the  calls repeatedly (sometimes recursively). The limit set by \fImatch_limit\fP is
1504  number of times this function is called during a match, which has the effect of  imposed on the number of times this function is called during a match, which
1505  limiting the amount of backtracking that can take place. For patterns that are  has the effect of limiting the amount of backtracking that can take place. For
1506  not anchored, the count restarts from zero for each position in the subject  patterns that are not anchored, the count restarts from zero for each position
1507  string.  in the subject string.
1508    .P
1509    When \fBpcre_exec()\fP is called with a pattern that was successfully studied
1510    with a JIT option, the way that the matching is executed is entirely different.
1511    However, there is still the possibility of runaway matching that goes on for a
1512    very long time, and so the \fImatch_limit\fP value is also used in this case
1513    (but in a different way) to limit how long the matching can continue.
1514  .P  .P
1515  The default value for the limit can be set when PCRE is built; the default  The default value for the limit can be set when PCRE is built; the default
1516  default is 10 million, which handles all but the most extreme cases. You can  default is 10 million, which handles all but the most extreme cases. You can
# Line 1294  limits the depth of recursion. The recur Line 1525  limits the depth of recursion. The recur
1525  total number of calls, because not all calls to \fBmatch()\fP are recursive.  total number of calls, because not all calls to \fBmatch()\fP are recursive.
1526  This limit is of use only if it is set smaller than \fImatch_limit\fP.  This limit is of use only if it is set smaller than \fImatch_limit\fP.
1527  .P  .P
1528  Limiting the recursion depth limits the amount of stack that can be used, or,  Limiting the recursion depth limits the amount of machine stack that can be
1529  when PCRE has been compiled to use memory on the heap instead of the stack, the  used, or, when PCRE has been compiled to use memory on the heap instead of the
1530  amount of heap memory that can be used.  stack, the amount of heap memory that can be used. This limit is not relevant,
1531    and is ignored, when matching is done using JIT compiled code.
1532  .P  .P
1533  The default value for \fImatch_limit_recursion\fP can be set when PCRE is  The default value for \fImatch_limit_recursion\fP can be set when PCRE is
1534  built; the default default is the same value as the default for  built; the default default is the same value as the default for
# Line 1327  called. See the Line 1559  called. See the
1559  documentation for a discussion of saving compiled patterns for later use.  documentation for a discussion of saving compiled patterns for later use.
1560  .P  .P
1561  If PCRE_EXTRA_MARK is set in the \fIflags\fP field, the \fImark\fP field must  If PCRE_EXTRA_MARK is set in the \fIflags\fP field, the \fImark\fP field must
1562  be set to point to a \fBchar *\fP variable. If the pattern contains any  be set to point to a suitable variable. If the pattern contains any
1563  backtracking control verbs such as (*MARK:NAME), and the execution ends up with  backtracking control verbs such as (*MARK:NAME), and the execution ends up with
1564  a name to pass back, a pointer to the name string (zero terminated) is placed  a name to pass back, a pointer to the name string (zero terminated) is placed
1565  in the variable pointed to by the \fImark\fP field. The names are within the  in the variable pointed to by the \fImark\fP field. The names are within the
1566  compiled pattern; if you wish to retain such a name you must copy it before  compiled pattern; if you wish to retain such a name you must copy it before
1567  freeing the memory of a compiled pattern. If there is no name to pass back, the  freeing the memory of a compiled pattern. If there is no name to pass back, the
1568  variable pointed to by the \fImark\fP field set to NULL. For details of the  variable pointed to by the \fImark\fP field is set to NULL. For details of the
1569  backtracking control verbs, see the section entitled  backtracking control verbs, see the section entitled
1570  .\" HTML <a href="pcrepattern#backtrackcontrol">  .\" HTML <a href="pcrepattern#backtrackcontrol">
1571  .\" </a>  .\" </a>
# Line 1353  documentation. Line 1585  documentation.
1585  The unused bits of the \fIoptions\fP argument for \fBpcre_exec()\fP must be  The unused bits of the \fIoptions\fP argument for \fBpcre_exec()\fP must be
1586  zero. The only bits that may be set are PCRE_ANCHORED, PCRE_NEWLINE_\fIxxx\fP,  zero. The only bits that may be set are PCRE_ANCHORED, PCRE_NEWLINE_\fIxxx\fP,
1587  PCRE_NOTBOL, PCRE_NOTEOL, PCRE_NOTEMPTY, PCRE_NOTEMPTY_ATSTART,  PCRE_NOTBOL, PCRE_NOTEOL, PCRE_NOTEMPTY, PCRE_NOTEMPTY_ATSTART,
1588  PCRE_NO_START_OPTIMIZE, PCRE_NO_UTF8_CHECK, PCRE_PARTIAL_SOFT, and  PCRE_NO_START_OPTIMIZE, PCRE_NO_UTF8_CHECK, PCRE_PARTIAL_HARD, and
1589  PCRE_PARTIAL_HARD.  PCRE_PARTIAL_SOFT.
1590    .P
1591    If the pattern was successfully studied with one of the just-in-time (JIT)
1592    compile options, the only supported options for JIT execution are
1593    PCRE_NO_UTF8_CHECK, PCRE_NOTBOL, PCRE_NOTEOL, PCRE_NOTEMPTY,
1594    PCRE_NOTEMPTY_ATSTART, PCRE_PARTIAL_HARD, and PCRE_PARTIAL_SOFT. If an
1595    unsupported option is used, JIT execution is disabled and the normal
1596    interpretive code in \fBpcre_exec()\fP is run.
1597  .sp  .sp
1598    PCRE_ANCHORED    PCRE_ANCHORED
1599  .sp  .sp
# Line 1450  the Line 1689  the
1689  .\" HREF  .\" HREF
1690  \fBpcredemo\fP  \fBpcredemo\fP
1691  .\"  .\"
1692  sample program. In the most general case, you have to check to see if the  sample program. In the most general case, you have to check to see if the
1693  newline convention recognizes CRLF as a newline, and if so, and the current  newline convention recognizes CRLF as a newline, and if so, and the current
1694  character is CR followed by LF, advance the starting offset by two characters  character is CR followed by LF, advance the starting offset by two characters
1695  instead of one.  instead of one.
1696  .sp  .sp
# Line 1471  a pre-scan of the subject that takes pla Line 1710  a pre-scan of the subject that takes pla
1710  The PCRE_NO_START_OPTIMIZE option disables the start-up optimizations, possibly  The PCRE_NO_START_OPTIMIZE option disables the start-up optimizations, possibly
1711  causing performance to suffer, but ensuring that in cases where the result is  causing performance to suffer, but ensuring that in cases where the result is
1712  "no match", the callouts do occur, and that items such as (*COMMIT) and (*MARK)  "no match", the callouts do occur, and that items such as (*COMMIT) and (*MARK)
1713  are considered at every possible starting position in the subject string.  are considered at every possible starting position in the subject string. If
1714    PCRE_NO_START_OPTIMIZE is set at compile time, it cannot be unset at matching
1715    time. The use of PCRE_NO_START_OPTIMIZE disables JIT execution; when it is set,
1716    matching is always done using interpretively.
1717    .P
1718  Setting PCRE_NO_START_OPTIMIZE can change the outcome of a matching operation.  Setting PCRE_NO_START_OPTIMIZE can change the outcome of a matching operation.
1719  Consider the pattern  Consider the pattern
1720  .sp  .sp
# Line 1503  returned. Line 1746  returned.
1746  .sp  .sp
1747  When PCRE_UTF8 is set at compile time, the validity of the subject as a UTF-8  When PCRE_UTF8 is set at compile time, the validity of the subject as a UTF-8
1748  string is automatically checked when \fBpcre_exec()\fP is subsequently called.  string is automatically checked when \fBpcre_exec()\fP is subsequently called.
1749  The value of \fIstartoffset\fP is also checked to ensure that it points to the  The entire string is checked before any other processing takes place. The value
1750  start of a UTF-8 character. There is a discussion about the validity of UTF-8  of \fIstartoffset\fP is also checked to ensure that it points to the start of a
1751  strings in the  UTF-8 character. There is a discussion about the
1752  .\" HTML <a href="pcre.html#utf8strings">  .\" HTML <a href="pcreunicode.html#utf8strings">
1753  .\" </a>  .\" </a>
1754  section on UTF-8 support  validity of UTF-8 strings
1755  .\"  .\"
1756  in the main  in the
1757  .\" HREF  .\" HREF
1758  \fBpcre\fP  \fBpcreunicode\fP
1759    .\"
1760    page. If an invalid sequence of bytes is found, \fBpcre_exec()\fP returns the
1761    error PCRE_ERROR_BADUTF8 or, if PCRE_PARTIAL_HARD is set and the problem is a
1762    truncated character at the end of the subject, PCRE_ERROR_SHORTUTF8. In both
1763    cases, information about the precise nature of the error may also be returned
1764    (see the descriptions of these errors in the section entitled \fIError return
1765    values from\fP \fBpcre_exec()\fP
1766    .\" HTML <a href="#errorlist">
1767    .\" </a>
1768    below).
1769  .\"  .\"
1770  page. If an invalid UTF-8 sequence of bytes is found, \fBpcre_exec()\fP returns  If \fIstartoffset\fP contains a value that does not point to the start of a
1771  the error PCRE_ERROR_BADUTF8. If \fIstartoffset\fP contains an invalid value,  UTF-8 character (or to the end of the subject), PCRE_ERROR_BADUTF8_OFFSET is
1772  PCRE_ERROR_BADUTF8_OFFSET is returned.  returned.
1773  .P  .P
1774  If you already know that your subject is valid, and you want to skip these  If you already know that your subject is valid, and you want to skip these
1775  checks for performance reasons, you can set the PCRE_NO_UTF8_CHECK option when  checks for performance reasons, you can set the PCRE_NO_UTF8_CHECK option when
1776  calling \fBpcre_exec()\fP. You might want to do this for the second and  calling \fBpcre_exec()\fP. You might want to do this for the second and
1777  subsequent calls to \fBpcre_exec()\fP if you are making repeated calls to find  subsequent calls to \fBpcre_exec()\fP if you are making repeated calls to find
1778  all the matches in a single subject string. However, you should be sure that  all the matches in a single subject string. However, you should be sure that
1779  the value of \fIstartoffset\fP points to the start of a UTF-8 character. When  the value of \fIstartoffset\fP points to the start of a character (or the end
1780  PCRE_NO_UTF8_CHECK is set, the effect of passing an invalid UTF-8 string as a  of the subject). When PCRE_NO_UTF8_CHECK is set, the effect of passing an
1781  subject, or a value of \fIstartoffset\fP that does not point to the start of a  invalid string as a subject or an invalid value of \fIstartoffset\fP is
1782  UTF-8 character, is undefined. Your program may crash.  undefined. Your program may crash.
1783  .sp  .sp
1784    PCRE_PARTIAL_HARD    PCRE_PARTIAL_HARD
1785    PCRE_PARTIAL_SOFT    PCRE_PARTIAL_SOFT
# Line 1544  but only if no complete match can be fou Line 1797  but only if no complete match can be fou
1797  If PCRE_PARTIAL_HARD is set, it overrides PCRE_PARTIAL_SOFT. In this case, if a  If PCRE_PARTIAL_HARD is set, it overrides PCRE_PARTIAL_SOFT. In this case, if a
1798  partial match is found, \fBpcre_exec()\fP immediately returns  partial match is found, \fBpcre_exec()\fP immediately returns
1799  PCRE_ERROR_PARTIAL, without considering any other alternatives. In other words,  PCRE_ERROR_PARTIAL, without considering any other alternatives. In other words,
1800  when PCRE_PARTIAL_HARD is set, a partial match is considered to be more  when PCRE_PARTIAL_HARD is set, a partial match is considered to be more
1801  important that an alternative complete match.  important that an alternative complete match.
1802  .P  .P
1803  In both cases, the portion of the string that was inspected when the partial  In both cases, the portion of the string that was inspected when the partial
# Line 1555  discussion of partial and multi-segment Line 1808  discussion of partial and multi-segment
1808  .\"  .\"
1809  documentation.  documentation.
1810  .  .
1811    .
1812  .SS "The string to be matched by \fBpcre_exec()\fP"  .SS "The string to be matched by \fBpcre_exec()\fP"
1813  .rs  .rs
1814  .sp  .sp
1815  The subject string is passed to \fBpcre_exec()\fP as a pointer in  The subject string is passed to \fBpcre_exec()\fP as a pointer in
1816  \fIsubject\fP, a length (in bytes) in \fIlength\fP, and a starting byte offset  \fIsubject\fP, a length in bytes in \fIlength\fP, and a starting byte offset
1817  in \fIstartoffset\fP. In UTF-8 mode, the byte offset must point to the start of  in \fIstartoffset\fP. If this is negative or greater than the length of the
1818  a UTF-8 character. Unlike the pattern string, the subject may contain binary  subject, \fBpcre_exec()\fP returns PCRE_ERROR_BADOFFSET. When the starting
1819  zero bytes. When the starting offset is zero, the search for a match starts at  offset is zero, the search for a match starts at the beginning of the subject,
1820  the beginning of the subject, and this is by far the most common case.  and this is by far the most common case. In UTF-8 mode, the byte offset must
1821    point to the start of a UTF-8 character (or the end of the subject). Unlike the
1822    pattern string, the subject may contain binary zero bytes.
1823  .P  .P
1824  A non-zero starting offset is useful when searching for another match in the  A non-zero starting offset is useful when searching for another match in the
1825  same subject by calling \fBpcre_exec()\fP again after a previous success.  same subject by calling \fBpcre_exec()\fP again after a previous success.
# Line 1583  start of the subject, which is deemed to Line 1839  start of the subject, which is deemed to
1839  set to 4, it finds the second occurrence of "iss" because it is able to look  set to 4, it finds the second occurrence of "iss" because it is able to look
1840  behind the starting point to discover that it is preceded by a letter.  behind the starting point to discover that it is preceded by a letter.
1841  .P  .P
1842    Finding all the matches in a subject is tricky when the pattern can match an
1843    empty string. It is possible to emulate Perl's /g behaviour by first trying the
1844    match again at the same offset, with the PCRE_NOTEMPTY_ATSTART and
1845    PCRE_ANCHORED options, and then if that fails, advancing the starting offset
1846    and trying an ordinary match again. There is some code that demonstrates how to
1847    do this in the
1848    .\" HREF
1849    \fBpcredemo\fP
1850    .\"
1851    sample program. In the most general case, you have to check to see if the
1852    newline convention recognizes CRLF as a newline, and if so, and the current
1853    character is CR followed by LF, advance the starting offset by two characters
1854    instead of one.
1855    .P
1856  If a non-zero starting offset is passed when the pattern is anchored, one  If a non-zero starting offset is passed when the pattern is anchored, one
1857  attempt to match at the given offset is made. This can only succeed if the  attempt to match at the given offset is made. This can only succeed if the
1858  pattern does not require the match to be at the start of the subject.  pattern does not require the match to be at the start of the subject.
1859  .  .
1860    .
1861  .SS "How \fBpcre_exec()\fP returns captured substrings"  .SS "How \fBpcre_exec()\fP returns captured substrings"
1862  .rs  .rs
1863  .sp  .sp
# Line 1630  string that it matched that is returned. Line 1901  string that it matched that is returned.
1901  .P  .P
1902  If the vector is too small to hold all the captured substring offsets, it is  If the vector is too small to hold all the captured substring offsets, it is
1903  used as far as possible (up to two-thirds of its length), and the function  used as far as possible (up to two-thirds of its length), and the function
1904  returns a value of zero. If the substring offsets are not of interest,  returns a value of zero. If neither the actual string matched nor any captured
1905  \fBpcre_exec()\fP may be called with \fIovector\fP passed as NULL and  substrings are of interest, \fBpcre_exec()\fP may be called with \fIovector\fP
1906  \fIovecsize\fP as zero. However, if the pattern contains back references and  passed as NULL and \fIovecsize\fP as zero. However, if the pattern contains
1907  the \fIovector\fP is not big enough to remember the related substrings, PCRE  back references and the \fIovector\fP is not big enough to remember the related
1908  has to get additional memory for use during matching. Thus it is usually  substrings, PCRE has to get additional memory for use during matching. Thus it
1909  advisable to supply an \fIovector\fP.  is usually advisable to supply an \fIovector\fP of reasonable size.
1910    .P
1911    There are some cases where zero is returned (indicating vector overflow) when
1912    in fact the vector is exactly the right size for the final match. For example,
1913    consider the pattern
1914    .sp
1915      (a)(?:(b)c|bd)
1916    .sp
1917    If a vector of 6 elements (allowing for only 1 captured substring) is given
1918    with subject string "abd", \fBpcre_exec()\fP will try to set the second
1919    captured string, thereby recording a vector overflow, before failing to match
1920    "c" and backing up to try the second alternative. The zero return, however,
1921    does correctly indicate that the maximum number of slots (namely 2) have been
1922    filled. In similar cases where there is temporary overflow, but the final
1923    number of used slots is actually less than the maximum, a non-zero value is
1924    returned.
1925  .P  .P
1926  The \fBpcre_fullinfo()\fP function can be used to find out how many capturing  The \fBpcre_fullinfo()\fP function can be used to find out how many capturing
1927  subpatterns there are in a compiled pattern. The smallest size for  subpatterns there are in a compiled pattern. The smallest size for
# Line 1653  Offset values that correspond to unused Line 1939  Offset values that correspond to unused
1939  expression are also set to -1. For example, if the string "abc" is matched  expression are also set to -1. For example, if the string "abc" is matched
1940  against the pattern (abc)(x(yz)?)? subpatterns 2 and 3 are not matched. The  against the pattern (abc)(x(yz)?)? subpatterns 2 and 3 are not matched. The
1941  return from the function is 2, because the highest used capturing subpattern  return from the function is 2, because the highest used capturing subpattern
1942  number is 1. However, you can refer to the offsets for the second and third  number is 1, and the offsets for for the second and third capturing subpatterns
1943  capturing subpatterns if you wish (assuming the vector is large enough, of  (assuming the vector is large enough, of course) are set to -1.
1944  course).  .P
1945    \fBNote\fP: Elements in the first two-thirds of \fIovector\fP that do not
1946    correspond to capturing parentheses in the pattern are never changed. That is,
1947    if a pattern contains \fIn\fP capturing parentheses, no more than
1948    \fIovector[0]\fP to \fIovector[2n+1]\fP are set by \fBpcre_exec()\fP. The other
1949    elements (in the first two-thirds) retain whatever values they previously had.
1950  .P  .P
1951  Some convenience functions are provided for extracting the captured substrings  Some convenience functions are provided for extracting the captured substrings
1952  as separate strings. These are described below.  as separate strings. These are described below.
1953  .  .
1954    .
1955  .\" HTML <a name="errorlist"></a>  .\" HTML <a name="errorlist"></a>
1956  .SS "Error return values from \fBpcre_exec()\fP"  .SS "Error return values from \fBpcre_exec()\fP"
1957  .rs  .rs
# Line 1729  documentation for details. Line 2021  documentation for details.
2021  .sp  .sp
2022    PCRE_ERROR_BADUTF8        (-10)    PCRE_ERROR_BADUTF8        (-10)
2023  .sp  .sp
2024  A string that contains an invalid UTF-8 byte sequence was passed as a subject.  A string that contains an invalid UTF-8 byte sequence was passed as a subject,
2025    and the PCRE_NO_UTF8_CHECK option was not set. If the size of the output vector
2026    (\fIovecsize\fP) is at least 2, the byte offset to the start of the the invalid
2027    UTF-8 character is placed in the first element, and a reason code is placed in
2028    the second element. The reason codes are listed in the
2029    .\" HTML <a href="#badutf8reasons">
2030    .\" </a>
2031    following section.
2032    .\"
2033    For backward compatibility, if PCRE_PARTIAL_HARD is set and the problem is a
2034    truncated UTF-8 character at the end of the subject (reason codes 1 to 5),
2035    PCRE_ERROR_SHORTUTF8 is returned instead of PCRE_ERROR_BADUTF8.
2036  .sp  .sp
2037    PCRE_ERROR_BADUTF8_OFFSET (-11)    PCRE_ERROR_BADUTF8_OFFSET (-11)
2038  .sp  .sp
2039  The UTF-8 byte sequence that was passed as a subject was valid, but the value  The UTF-8 byte sequence that was passed as a subject was checked and found to
2040  of \fIstartoffset\fP did not point to the beginning of a UTF-8 character.  be valid (the PCRE_NO_UTF8_CHECK option was not set), but the value of
2041    \fIstartoffset\fP did not point to the beginning of a UTF-8 character or the
2042    end of the subject.
2043  .sp  .sp
2044    PCRE_ERROR_PARTIAL        (-12)    PCRE_ERROR_PARTIAL        (-12)
2045  .sp  .sp
# Line 1769  description above. Line 2074  description above.
2074    PCRE_ERROR_BADNEWLINE     (-23)    PCRE_ERROR_BADNEWLINE     (-23)
2075  .sp  .sp
2076  An invalid combination of PCRE_NEWLINE_\fIxxx\fP options was given.  An invalid combination of PCRE_NEWLINE_\fIxxx\fP options was given.
2077    .sp
2078      PCRE_ERROR_BADOFFSET      (-24)
2079    .sp
2080    The value of \fIstartoffset\fP was negative or greater than the length of the
2081    subject, that is, the value in \fIlength\fP.
2082    .sp
2083      PCRE_ERROR_SHORTUTF8      (-25)
2084    .sp
2085    This error is returned instead of PCRE_ERROR_BADUTF8 when the subject string
2086    ends with a truncated UTF-8 character and the PCRE_PARTIAL_HARD option is set.
2087    Information about the failure is returned as for PCRE_ERROR_BADUTF8. It is in
2088    fact sufficient to detect this case, but this special error code for
2089    PCRE_PARTIAL_HARD precedes the implementation of returned information; it is
2090    retained for backwards compatibility.
2091    .sp
2092      PCRE_ERROR_RECURSELOOP    (-26)
2093    .sp
2094    This error is returned when \fBpcre_exec()\fP detects a recursion loop within
2095    the pattern. Specifically, it means that either the whole pattern or a
2096    subpattern has been called recursively for the second time at the same position
2097    in the subject string. Some simple patterns that might do this are detected and
2098    faulted at compile time, but more complicated cases, in particular mutual
2099    recursions between two different subpatterns, cannot be detected until run
2100    time.
2101    .sp
2102      PCRE_ERROR_JIT_STACKLIMIT (-27)
2103    .sp
2104    This error is returned when a pattern that was successfully studied using a
2105    JIT compile option is being matched, but the memory available for the
2106    just-in-time processing stack is not large enough. See the
2107    .\" HREF
2108    \fBpcrejit\fP
2109    .\"
2110    documentation for more details.
2111    .sp
2112      PCRE_ERROR_BADMODE        (-28)
2113    .sp
2114    This error is given if a pattern that was compiled by the 8-bit library is
2115    passed to a 16-bit library function, or vice versa.
2116    .sp
2117      PCRE_ERROR_BADENDIANNESS  (-29)
2118    .sp
2119    This error is given if a pattern that was compiled and saved is reloaded on a
2120    host with different endianness. The utility function
2121    \fBpcre_pattern_to_host_byte_order()\fP can be used to convert such a pattern
2122    so that it runs on the new host.
2123  .P  .P
2124  Error numbers -16 to -20 and -22 are not used by \fBpcre_exec()\fP.  Error numbers -16 to -20, -22, and -30 are not used by \fBpcre_exec()\fP.
2125    .
2126    .
2127    .\" HTML <a name="badutf8reasons"></a>
2128    .SS "Reason codes for invalid UTF-8 strings"
2129    .rs
2130    .sp
2131    This section applies only to the 8-bit library. The corresponding information
2132    for the 16-bit library is given in the
2133    .\" HREF
2134    \fBpcre16\fP
2135    .\"
2136    page.
2137    .P
2138    When \fBpcre_exec()\fP returns either PCRE_ERROR_BADUTF8 or
2139    PCRE_ERROR_SHORTUTF8, and the size of the output vector (\fIovecsize\fP) is at
2140    least 2, the offset of the start of the invalid UTF-8 character is placed in
2141    the first output vector element (\fIovector[0]\fP) and a reason code is placed
2142    in the second element (\fIovector[1]\fP). The reason codes are given names in
2143    the \fBpcre.h\fP header file:
2144    .sp
2145      PCRE_UTF8_ERR1
2146      PCRE_UTF8_ERR2
2147      PCRE_UTF8_ERR3
2148      PCRE_UTF8_ERR4
2149      PCRE_UTF8_ERR5
2150    .sp
2151    The string ends with a truncated UTF-8 character; the code specifies how many
2152    bytes are missing (1 to 5). Although RFC 3629 restricts UTF-8 characters to be
2153    no longer than 4 bytes, the encoding scheme (originally defined by RFC 2279)
2154    allows for up to 6 bytes, and this is checked first; hence the possibility of
2155    4 or 5 missing bytes.
2156    .sp
2157      PCRE_UTF8_ERR6
2158      PCRE_UTF8_ERR7
2159      PCRE_UTF8_ERR8
2160      PCRE_UTF8_ERR9
2161      PCRE_UTF8_ERR10
2162    .sp
2163    The two most significant bits of the 2nd, 3rd, 4th, 5th, or 6th byte of the
2164    character do not have the binary value 0b10 (that is, either the most
2165    significant bit is 0, or the next bit is 1).
2166    .sp
2167      PCRE_UTF8_ERR11
2168      PCRE_UTF8_ERR12
2169    .sp
2170    A character that is valid by the RFC 2279 rules is either 5 or 6 bytes long;
2171    these code points are excluded by RFC 3629.
2172    .sp
2173      PCRE_UTF8_ERR13
2174    .sp
2175    A 4-byte character has a value greater than 0x10fff; these code points are
2176    excluded by RFC 3629.
2177    .sp
2178      PCRE_UTF8_ERR14
2179    .sp
2180    A 3-byte character has a value in the range 0xd800 to 0xdfff; this range of
2181    code points are reserved by RFC 3629 for use with UTF-16, and so are excluded
2182    from UTF-8.
2183    .sp
2184      PCRE_UTF8_ERR15
2185      PCRE_UTF8_ERR16
2186      PCRE_UTF8_ERR17
2187      PCRE_UTF8_ERR18
2188      PCRE_UTF8_ERR19
2189    .sp
2190    A 2-, 3-, 4-, 5-, or 6-byte character is "overlong", that is, it codes for a
2191    value that can be represented by fewer bytes, which is invalid. For example,
2192    the two bytes 0xc0, 0xae give the value 0x2e, whose correct coding uses just
2193    one byte.
2194    .sp
2195      PCRE_UTF8_ERR20
2196    .sp
2197    The two most significant bits of the first byte of a character have the binary
2198    value 0b10 (that is, the most significant bit is 1 and the second is 0). Such a
2199    byte can only validly occur as the second or subsequent byte of a multi-byte
2200    character.
2201    .sp
2202      PCRE_UTF8_ERR21
2203    .sp
2204    The first byte of a character has the value 0xfe or 0xff. These values can
2205    never occur in a valid UTF-8 string.
2206  .  .
2207  .  .
2208  .SH "EXTRACTING CAPTURED SUBSTRINGS BY NUMBER"  .SH "EXTRACTING CAPTURED SUBSTRINGS BY NUMBER"
# Line 1935  names are not included in the compiled c Line 2367  names are not included in the compiled c
2367  numbers. For this reason, the use of different names for subpatterns of the  numbers. For this reason, the use of different names for subpatterns of the
2368  same number causes an error at compile time.  same number causes an error at compile time.
2369  .  .
2370    .
2371  .SH "DUPLICATE SUBPATTERN NAMES"  .SH "DUPLICATE SUBPATTERN NAMES"
2372  .rs  .rs
2373  .sp  .sp
# Line 1968  fourth are pointers to variables which a Line 2401  fourth are pointers to variables which a
2401  has run, they point to the first and last entries in the name-to-number table  has run, they point to the first and last entries in the name-to-number table
2402  for the given name. The function itself returns the length of each entry, or  for the given name. The function itself returns the length of each entry, or
2403  PCRE_ERROR_NOSUBSTRING (-7) if there are none. The format of the table is  PCRE_ERROR_NOSUBSTRING (-7) if there are none. The format of the table is
2404  described above in the section entitled \fIInformation about a pattern\fP.  described above in the section entitled \fIInformation about a pattern\fP
2405    .\" HTML <a href="#infoaboutpattern">
2406    .\" </a>
2407    above.
2408    .\"
2409  Given all the relevant entries for the name, you can extract each of their  Given all the relevant entries for the name, you can extract each of their
2410  numbers, and hence the captured data, if any.  numbers, and hence the captured data, if any.
2411  .  .
# Line 1995  other alternatives. Ultimately, when it Line 2432  other alternatives. Ultimately, when it
2432  will yield PCRE_ERROR_NOMATCH.  will yield PCRE_ERROR_NOMATCH.
2433  .  .
2434  .  .
2435    .SH "OBTAINING AN ESTIMATE OF STACK USAGE"
2436    .rs
2437    .sp
2438    Matching certain patterns using \fBpcre_exec()\fP can use a lot of process
2439    stack, which in certain environments can be rather limited in size. Some users
2440    find it helpful to have an estimate of the amount of stack that is used by
2441    \fBpcre_exec()\fP, to help them set recursion limits, as described in the
2442    .\" HREF
2443    \fBpcrestack\fP
2444    .\"
2445    documentation. The estimate that is output by \fBpcretest\fP when called with
2446    the \fB-m\fP and \fB-C\fP options is obtained by calling \fBpcre_exec\fP with
2447    the values NULL, NULL, NULL, -999, and -999 for its first five arguments.
2448    .P
2449    Normally, if its first argument is NULL, \fBpcre_exec()\fP immediately returns
2450    the negative error code PCRE_ERROR_NULL, but with this special combination of
2451    arguments, it returns instead a negative number whose absolute value is the
2452    approximate stack frame size in bytes. (A negative number is used so that it is
2453    clear that no match has happened.) The value is approximate because in some
2454    cases, recursive calls to \fBpcre_exec()\fP occur when there are one or two
2455    additional variables on the stack.
2456    .P
2457    If PCRE has been compiled to use the heap instead of the stack for recursion,
2458    the value returned is the size of each block that is obtained from the heap.
2459    .
2460    .
2461  .\" HTML <a name="dfamatch"></a>  .\" HTML <a name="dfamatch"></a>
2462  .SH "MATCHING A PATTERN: THE ALTERNATIVE FUNCTION"  .SH "MATCHING A PATTERN: THE ALTERNATIVE FUNCTION"
2463  .rs  .rs
# Line 2098  match. There is more discussion of this Line 2561  match. There is more discussion of this
2561  .\"  .\"
2562  documentation.  documentation.
2563  .  .
2564    .
2565  .SS "Successful returns from \fBpcre_dfa_exec()\fP"  .SS "Successful returns from \fBpcre_dfa_exec()\fP"
2566  .rs  .rs
2567  .sp  .sp
# Line 2129  returns data, even though the meaning of Line 2593  returns data, even though the meaning of
2593  The strings are returned in reverse order of length; that is, the longest  The strings are returned in reverse order of length; that is, the longest
2594  matching string is given first. If there were too many matches to fit into  matching string is given first. If there were too many matches to fit into
2595  \fIovector\fP, the yield of the function is zero, and the vector is filled with  \fIovector\fP, the yield of the function is zero, and the vector is filled with
2596  the longest matches.  the longest matches. Unlike \fBpcre_exec()\fP, \fBpcre_dfa_exec()\fP can use
2597    the entire \fIovector\fP for returning matched strings.
2598    .
2599  .  .
2600  .SS "Error returns from \fBpcre_dfa_exec()\fP"  .SS "Error returns from \fBpcre_dfa_exec()\fP"
2601  .rs  .rs
# Line 2158  group. These are not supported. Line 2624  group. These are not supported.
2624    PCRE_ERROR_DFA_UMLIMIT    (-18)    PCRE_ERROR_DFA_UMLIMIT    (-18)
2625  .sp  .sp
2626  This return is given if \fBpcre_dfa_exec()\fP is called with an \fIextra\fP  This return is given if \fBpcre_dfa_exec()\fP is called with an \fIextra\fP
2627  block that contains a setting of the \fImatch_limit\fP field. This is not  block that contains a setting of the \fImatch_limit\fP or
2628  supported (it is meaningless).  \fImatch_limit_recursion\fP fields. This is not supported (these fields are
2629    meaningless for DFA matching).
2630  .sp  .sp
2631    PCRE_ERROR_DFA_WSSIZE     (-19)    PCRE_ERROR_DFA_WSSIZE     (-19)
2632  .sp  .sp
# Line 2172  When a recursive subpattern is processed Line 2639  When a recursive subpattern is processed
2639  recursively, using private vectors for \fIovector\fP and \fIworkspace\fP. This  recursively, using private vectors for \fIovector\fP and \fIworkspace\fP. This
2640  error is given if the output vector is not large enough. This should be  error is given if the output vector is not large enough. This should be
2641  extremely rare, as a vector of size 1000 is used.  extremely rare, as a vector of size 1000 is used.
2642    .sp
2643      PCRE_ERROR_DFA_BADRESTART (-30)
2644    .sp
2645    When \fBpcre_dfa_exec()\fP is called with the \fBPCRE_DFA_RESTART\fP option,
2646    some plausibility checks are made on the contents of the workspace, which
2647    should contain data about the previous partial match. If any of these checks
2648    fail, this error is given.
2649  .  .
2650  .  .
2651  .SH "SEE ALSO"  .SH "SEE ALSO"
2652  .rs  .rs
2653  .sp  .sp
2654  \fBpcrebuild\fP(3), \fBpcrecallout\fP(3), \fBpcrecpp(3)\fP(3),  \fBpcre16\fP(3), \fBpcrebuild\fP(3), \fBpcrecallout\fP(3), \fBpcrecpp(3)\fP(3),
2655  \fBpcrematching\fP(3), \fBpcrepartial\fP(3), \fBpcreposix\fP(3),  \fBpcrematching\fP(3), \fBpcrepartial\fP(3), \fBpcreposix\fP(3),
2656  \fBpcreprecompile\fP(3), \fBpcresample\fP(3), \fBpcrestack\fP(3).  \fBpcreprecompile\fP(3), \fBpcresample\fP(3), \fBpcrestack\fP(3).
2657  .  .
# Line 2196  Cambridge CB2 3QH, England. Line 2670  Cambridge CB2 3QH, England.
2670  .rs  .rs
2671  .sp  .sp
2672  .nf  .nf
2673  Last updated: 01 November 2010  Last updated: 28 August 2012
2674  Copyright (c) 1997-2010 University of Cambridge.  Copyright (c) 1997-2012 University of Cambridge.
2675  .fi  .fi

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