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revision 568 by ph10, Sat Nov 6 17:36:26 2010 UTC revision 950 by ph10, Sat Mar 10 09:23:27 2012 UTC
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1  .TH PCREAPI 3  .TH PCREAPI 3
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 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 546  unescaped # outside a character class an Line 649  unescaped # outside a character class an
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. Whitespace 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 614  preceding sequences should be recognized Line 742  preceding sequences should be recognized
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 (formfeed, 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 whitespace 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  .sp  .sp
930  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
931  be used if the limits were changed when PCRE was built.  be used if the limits were changed when PCRE was built.
932  .  .
933  .  .
934    .\" HTML <a name="studyingapattern"></a>
935  .SH "STUDYING A PATTERN"  .SH "STUDYING A PATTERN"
936  .rs  .rs
937  .sp  .sp
# Line 818  If studying the pattern does not produce Line 962  If studying the pattern does not produce
962  wants to pass any of the other fields to \fBpcre_exec()\fP or  wants to pass any of the other fields to \fBpcre_exec()\fP or
963  \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.
964  .P  .P
965  The second argument of \fBpcre_study()\fP contains option bits. At present, no  The second argument of \fBpcre_study()\fP contains option bits. There are three
966  options are defined, and this argument should always be zero.  options:
967    .sp
968      PCRE_STUDY_JIT_COMPILE
969      PCRE_STUDY_JIT_PARTIAL_HARD_COMPILE
970      PCRE_STUDY_JIT_PARTIAL_SOFT_COMPILE
971    .sp
972    If any of these are set, and the just-in-time compiler is available, the
973    pattern is further compiled into machine code that executes much faster than
974    the \fBpcre_exec()\fP interpretive matching function. If the just-in-time
975    compiler is not available, these options are ignored. All other bits in the
976    \fIoptions\fP argument must be zero.
977    .P
978    JIT compilation is a heavyweight optimization. It can take some time for
979    patterns to be analyzed, and for one-off matches and simple patterns the
980    benefit of faster execution might be offset by a much slower study time.
981    Not all patterns can be optimized by the JIT compiler. For those that cannot be
982    handled, matching automatically falls back to the \fBpcre_exec()\fP
983    interpreter. For more details, see the
984    .\" HREF
985    \fBpcrejit\fP
986    .\"
987    documentation.
988  .P  .P
989  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
990  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 993  static string that is part of the librar
993  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
994  sure that it has run successfully.  sure that it has run successfully.
995  .P  .P
996  This is a typical call to \fBpcre_study\fP():  When you are finished with a pattern, you can free the memory used for the
997    study data by calling \fBpcre_free_study()\fP. This function was added to the
998    API for release 8.20. For earlier versions, the memory could be freed with
999    \fBpcre_free()\fP, just like the pattern itself. This will still work in cases
1000    where JIT optimization is not used, but it is advisable to change to the new
1001    function when convenient.
1002    .P
1003    This is a typical way in which \fBpcre_study\fP() is used (except that in a
1004    real application there should be tests for errors):
1005  .sp  .sp
1006    pcre_extra *pe;    int rc;
1007    pe = pcre_study(    pcre *re;
1008      pcre_extra *sd;
1009      re = pcre_compile("pattern", 0, &error, &erroroffset, NULL);
1010      sd = pcre_study(
1011      re,             /* result of pcre_compile() */      re,             /* result of pcre_compile() */
1012      0,              /* no options exist */      0,              /* no options */
1013      &error);        /* set to NULL or points to a message */      &error);        /* set to NULL or points to a message */
1014      rc = pcre_exec(   /* see below for details of pcre_exec() options */
1015        re, sd, "subject", 7, 0, 0, ovector, 30);
1016      ...
1017      pcre_free_study(sd);
1018      pcre_free(re);
1019  .sp  .sp
1020  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
1021  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
# Line 847  in a calling program via the \fBpcre_ful Line 1028  in a calling program via the \fBpcre_ful
1028  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
1029  single fixed starting character. A bitmap of possible starting bytes is  single fixed starting character. A bitmap of possible starting bytes is
1030  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
1031  matching.  matching. (In 16-bit mode, the bitmap is used for 16-bit values less than 256.)
1032  .P  .P
1033  The two optimizations just described can be disabled by setting the  These two optimizations apply to both \fBpcre_exec()\fP and
1034  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.
1035  \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
1036  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,
1037  matching fails. See the discussion of PCRE_NO_START_OPTIMIZE  JIT execution is also disabled. You might want to do this if your pattern
1038    contains callouts or (*MARK) and you want to make use of these facilities in
1039    cases where matching fails. See the discussion of PCRE_NO_START_OPTIMIZE
1040  .\" HTML <a href="#execoptions">  .\" HTML <a href="#execoptions">
1041  .\" </a>  .\" </a>
1042  below.  below.
# Line 866  below. Line 1049  below.
1049  .sp  .sp
1050  PCRE handles caseless matching, and determines whether characters are letters,  PCRE handles caseless matching, and determines whether characters are letters,
1051  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
1052  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
1053  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
1054  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
1055  property support. Alternatively, the PCRE_UCP option can be set at compile  Unicode character property support. Alternatively, the PCRE_UCP option can be
1056  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
1057  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
1058  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
1059  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
1060    two.
1061  .P  .P
1062  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
1063  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 1102  one in which it was compiled. Passing ta
1102  below in the section on matching a pattern.  below in the section on matching a pattern.
1103  .  .
1104  .  .
1105    .\" HTML <a name="infoaboutpattern"></a>
1106  .SH "INFORMATION ABOUT A PATTERN"  .SH "INFORMATION ABOUT A PATTERN"
1107  .rs  .rs
1108  .sp  .sp
# Line 926  below in the section on matching a patte Line 1111  below in the section on matching a patte
1111  .B int \fIwhat\fP, void *\fIwhere\fP);  .B int \fIwhat\fP, void *\fIwhere\fP);
1112  .PP  .PP
1113  The \fBpcre_fullinfo()\fP function returns information about a compiled  The \fBpcre_fullinfo()\fP function returns information about a compiled
1114  pattern. It replaces the obsolete \fBpcre_info()\fP function, which is  pattern. It replaces the \fBpcre_info()\fP function, which was removed from the
1115  nevertheless retained for backwards compability (and is documented below).  library at version 8.30, after more than 10 years of obsolescence.
1116  .P  .P
1117  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
1118  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 1121  information is required, and the fourth
1121  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
1122  the following negative numbers:  the following negative numbers:
1123  .sp  .sp
1124    PCRE_ERROR_NULL       the argument \fIcode\fP was NULL    PCRE_ERROR_NULL           the argument \fIcode\fP was NULL
1125                          the argument \fIwhere\fP was NULL                              the argument \fIwhere\fP was NULL
1126    PCRE_ERROR_BADMAGIC   the "magic number" was not found    PCRE_ERROR_BADMAGIC       the "magic number" was not found
1127    PCRE_ERROR_BADOPTION  the value of \fIwhat\fP was invalid    PCRE_ERROR_BADENDIANNESS  the pattern was compiled with different
1128                                endianness
1129      PCRE_ERROR_BADOPTION      the value of \fIwhat\fP was invalid
1130  .sp  .sp
1131  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
1132  check against passing an arbitrary memory pointer. Here is a typical call of  check against passing an arbitrary memory pointer. The endianness error can
1133  \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
1134    a typical call of \fBpcre_fullinfo()\fP, to obtain the length of the compiled
1135    pattern:
1136  .sp  .sp
1137    int rc;    int rc;
1138    size_t length;    size_t length;
1139    rc = pcre_fullinfo(    rc = pcre_fullinfo(
1140      re,               /* result of pcre_compile() */      re,               /* result of pcre_compile() */
1141      pe,               /* result of pcre_study(), or NULL */      sd,               /* result of pcre_study(), or NULL */
1142      PCRE_INFO_SIZE,   /* what is required */      PCRE_INFO_SIZE,   /* what is required */
1143      &length);         /* where to put the data */      &length);         /* where to put the data */
1144  .sp  .sp
# Line 977  a NULL table pointer. Line 1166  a NULL table pointer.
1166  .sp  .sp
1167    PCRE_INFO_FIRSTBYTE    PCRE_INFO_FIRSTBYTE
1168  .sp  .sp
1169  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
1170  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,
1171  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
1172  still recognized for backwards compatibility.)  variable.
1173  .P  .P
1174  If there is a fixed first byte, for example, from a pattern such as  If there is a fixed first value, for example, the letter "c" from a pattern
1175  (cat|cow|coyote), its value is returned. Otherwise, if either  such as (cat|cow|coyote), its value is returned. In the 8-bit library, the
1176    value is always less than 256; in the 16-bit library the value can be up to
1177    0xffff.
1178    .P
1179    If there is no fixed first value, and if either
1180  .sp  .sp
1181  (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
1182  starts with "^", or  starts with "^", or
# Line 998  returned. For anchored patterns, -2 is r Line 1191  returned. For anchored patterns, -2 is r
1191    PCRE_INFO_FIRSTTABLE    PCRE_INFO_FIRSTTABLE
1192  .sp  .sp
1193  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
1194  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
1195  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
1196  fourth argument should point to an \fBunsigned char *\fP variable.  fourth argument should point to an \fBunsigned char *\fP variable.
1197  .sp  .sp
# Line 1014  Return 1 if the (?J) or (?-J) option set Line 1207  Return 1 if the (?J) or (?-J) option set
1207  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
1208  (?-J) set and unset the local PCRE_DUPNAMES option, respectively.  (?-J) set and unset the local PCRE_DUPNAMES option, respectively.
1209  .sp  .sp
1210      PCRE_INFO_JIT
1211    .sp
1212    Return 1 if the pattern was studied with one of the JIT options, and
1213    just-in-time compiling was successful. The fourth argument should point to an
1214    \fBint\fP variable. A return value of 0 means that JIT support is not available
1215    in this version of PCRE, or that the pattern was not studied with a JIT option,
1216    or that the JIT compiler could not handle this particular pattern. See the
1217    .\" HREF
1218    \fBpcrejit\fP
1219    .\"
1220    documentation for details of what can and cannot be handled.
1221    .sp
1222      PCRE_INFO_JITSIZE
1223    .sp
1224    If the pattern was successfully studied with a JIT option, return the size of
1225    the JIT compiled code, otherwise return zero. The fourth argument should point
1226    to a \fBsize_t\fP variable.
1227    .sp
1228    PCRE_INFO_LASTLITERAL    PCRE_INFO_LASTLITERAL
1229  .sp  .sp
1230  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
1231  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
1232  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
1233  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
1234  follows something of variable length. For example, for the pattern  only if it follows something of variable length. For example, for the pattern
1235  /^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
1236  is -1.  is -1.
1237  .sp  .sp
1238      PCRE_INFO_MAXLOOKBEHIND
1239    .sp
1240    Return the number of characters (NB not bytes) in the longest lookbehind
1241    assertion in the pattern. Note that the simple assertions \eb and \eB require a
1242    one-character lookbehind. This information is useful when doing multi-segment
1243    matching using the partial matching facilities.
1244    .sp
1245    PCRE_INFO_MINLENGTH    PCRE_INFO_MINLENGTH
1246  .sp  .sp
1247  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
1248  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
1249  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
1250  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
1251  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
1252  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
1253  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 1270  The map consists of a number of fixed-si
1270  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
1271  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
1272  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
1273  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
1274  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,
1275  rest of the entry is the corresponding name, zero terminated.  most significant byte first. In the 16-bit library, the pointer points to
1276    16-bit data units, the first of which contains the parenthesis number. The rest
1277    of the entry is the corresponding name, zero terminated.
1278  .P  .P
1279  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
1280  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 1293  table in the order in which they were fo
1293  necessarily the case because later subpatterns may have lower numbers.  necessarily the case because later subpatterns may have lower numbers.
1294  .P  .P
1295  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
1296  (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
1297  ignored):  space - including newlines - is ignored):
1298  .sp  .sp
1299  .\" JOIN  .\" JOIN
1300    (?<date> (?<year>(\ed\ed)?\ed\ed) -    (?<date> (?<year>(\ed\ed)?\ed\ed) -
# Line 1129  For such patterns, the PCRE_ANCHORED bit Line 1349  For such patterns, the PCRE_ANCHORED bit
1349  .sp  .sp
1350    PCRE_INFO_SIZE    PCRE_INFO_SIZE
1351  .sp  .sp
1352  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
1353  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
1354  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
1355  variable.  \fBpcre_compile()\fP. The value that is passed as the argument to
1356    \fBpcre_malloc()\fP when \fBpcre_compile()\fP is getting memory in which to
1357    place the compiled data is the value returned by this option plus the size of
1358    the \fBpcre\fP structure. Studying a compiled pattern, with or without JIT,
1359    does not alter the value returned by this option.
1360  .sp  .sp
1361    PCRE_INFO_STUDYSIZE    PCRE_INFO_STUDYSIZE
1362  .sp  .sp
1363  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
1364  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  
1365  study data, zero is returned. The fourth argument should point to a  study data, zero is returned. The fourth argument should point to a
1366  \fBsize_t\fP variable.  \fBsize_t\fP variable. The \fIstudy_data\fP field is set by \fBpcre_study()\fP
1367  .  to record information that will speed up matching (see the section entitled
1368  .  .\" HTML <a href="#studyingapattern">
1369  .SH "OBSOLETE INFO FUNCTION"  .\" </a>
1370  .rs  "Studying a pattern"
1371  .sp  .\"
1372  .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
1373  .B *\fIfirstcharptr\fP);  is made available via this option so that it can be saved and restored (see the
1374  .PP  .\" HREF
1375  The \fBpcre_info()\fP function is now obsolete because its interface is too  \fBpcreprecompile\fP
1376  restrictive to return all the available data about a compiled pattern. New  .\"
1377  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).  
1378  .  .
1379  .  .
1380  .SH "REFERENCE COUNTS"  .SH "REFERENCE COUNTS"
# Line 1203  is different. (This seems a highly unlik Line 1412  is different. (This seems a highly unlik
1412  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
1413  compiled pattern, which is passed in the \fIcode\fP argument. If the  compiled pattern, which is passed in the \fIcode\fP argument. If the
1414  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
1415  \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
1416  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
1417  also an alternative matching function, which is described  different subject strings with the same pattern.
1418    .P
1419    This function is the main matching facility of the library, and it operates in
1420    a Perl-like manner. For specialist use there is also an alternative matching
1421    function, which is described
1422  .\" HTML <a href="#dfamatch">  .\" HTML <a href="#dfamatch">
1423  .\" </a>  .\" </a>
1424  below  below
# Line 1236  Here is an example of a simple call to \ Line 1449  Here is an example of a simple call to \
1449      ovector,        /* vector of integers for substring information */      ovector,        /* vector of integers for substring information */
1450      30);            /* number of elements (NOT size in bytes) */      30);            /* number of elements (NOT size in bytes) */
1451  .  .
1452    .
1453  .\" HTML <a name="extradata"></a>  .\" HTML <a name="extradata"></a>
1454  .SS "Extra data for \fBpcre_exec()\fR"  .SS "Extra data for \fBpcre_exec()\fR"
1455  .rs  .rs
# Line 1248  fields (not necessarily in this order): Line 1462  fields (not necessarily in this order):
1462  .sp  .sp
1463    unsigned long int \fIflags\fP;    unsigned long int \fIflags\fP;
1464    void *\fIstudy_data\fP;    void *\fIstudy_data\fP;
1465      void *\fIexecutable_jit\fP;
1466    unsigned long int \fImatch_limit\fP;    unsigned long int \fImatch_limit\fP;
1467    unsigned long int \fImatch_limit_recursion\fP;    unsigned long int \fImatch_limit_recursion\fP;
1468    void *\fIcallout_data\fP;    void *\fIcallout_data\fP;
1469    const unsigned char *\fItables\fP;    const unsigned char *\fItables\fP;
1470    unsigned char **\fImark\fP;    unsigned char **\fImark\fP;
1471  .sp  .sp
1472  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
1473  are set. The flag bits are:  "PCRE_UCHAR16 **".
1474    .P
1475    The \fIflags\fP field is used to specify which of the other fields are set. The
1476    flag bits are:
1477  .sp  .sp
1478    PCRE_EXTRA_STUDY_DATA    PCRE_EXTRA_CALLOUT_DATA
1479      PCRE_EXTRA_EXECUTABLE_JIT
1480      PCRE_EXTRA_MARK
1481    PCRE_EXTRA_MATCH_LIMIT    PCRE_EXTRA_MATCH_LIMIT
1482    PCRE_EXTRA_MATCH_LIMIT_RECURSION    PCRE_EXTRA_MATCH_LIMIT_RECURSION
1483    PCRE_EXTRA_CALLOUT_DATA    PCRE_EXTRA_STUDY_DATA
1484    PCRE_EXTRA_TABLES    PCRE_EXTRA_TABLES
   PCRE_EXTRA_MARK  
1485  .sp  .sp
1486  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
1487  \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
1488  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
1489  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
1490    fields and their corresponding flag bits.
1491  .P  .P
1492  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
1493  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,
1494  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
1495  classic example is a pattern that uses nested unlimited repeats.  classic example is a pattern that uses nested unlimited repeats.
1496  .P  .P
1497  Internally, PCRE uses a function called \fBmatch()\fP which it calls repeatedly  Internally, \fBpcre_exec()\fP uses a function called \fBmatch()\fP, which it
1498  (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
1499  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
1500  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
1501  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
1502  string.  in the subject string.
1503    .P
1504    When \fBpcre_exec()\fP is called with a pattern that was successfully studied
1505    with a JIT option, the way that the matching is executed is entirely different.
1506    However, there is still the possibility of runaway matching that goes on for a
1507    very long time, and so the \fImatch_limit\fP value is also used in this case
1508    (but in a different way) to limit how long the matching can continue.
1509  .P  .P
1510  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
1511  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 1520  limits the depth of recursion. The recur
1520  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.
1521  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.
1522  .P  .P
1523  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
1524  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
1525  amount of heap memory that can be used.  stack, the amount of heap memory that can be used. This limit is not relevant,
1526    and is ignored, when matching is done using JIT compiled code.
1527  .P  .P
1528  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
1529  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 1554  called. See the
1554  documentation for a discussion of saving compiled patterns for later use.  documentation for a discussion of saving compiled patterns for later use.
1555  .P  .P
1556  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
1557  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
1558  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
1559  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
1560  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
1561  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
1562  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
1563  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
1564  backtracking control verbs, see the section entitled  backtracking control verbs, see the section entitled
1565  .\" HTML <a href="pcrepattern#backtrackcontrol">  .\" HTML <a href="pcrepattern#backtrackcontrol">
1566  .\" </a>  .\" </a>
# Line 1353  documentation. Line 1580  documentation.
1580  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
1581  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,
1582  PCRE_NOTBOL, PCRE_NOTEOL, PCRE_NOTEMPTY, PCRE_NOTEMPTY_ATSTART,  PCRE_NOTBOL, PCRE_NOTEOL, PCRE_NOTEMPTY, PCRE_NOTEMPTY_ATSTART,
1583  PCRE_NO_START_OPTIMIZE, PCRE_NO_UTF8_CHECK, PCRE_PARTIAL_SOFT, and  PCRE_NO_START_OPTIMIZE, PCRE_NO_UTF8_CHECK, PCRE_PARTIAL_HARD, and
1584  PCRE_PARTIAL_HARD.  PCRE_PARTIAL_SOFT.
1585    .P
1586    If the pattern was successfully studied with one of the just-in-time (JIT)
1587    compile options, the only supported options for JIT execution are
1588    PCRE_NO_UTF8_CHECK, PCRE_NOTBOL, PCRE_NOTEOL, PCRE_NOTEMPTY,
1589    PCRE_NOTEMPTY_ATSTART, PCRE_PARTIAL_HARD, and PCRE_PARTIAL_SOFT. If an
1590    unsupported option is used, JIT execution is disabled and the normal
1591    interpretive code in \fBpcre_exec()\fP is run.
1592  .sp  .sp
1593    PCRE_ANCHORED    PCRE_ANCHORED
1594  .sp  .sp
# Line 1450  the Line 1684  the
1684  .\" HREF  .\" HREF
1685  \fBpcredemo\fP  \fBpcredemo\fP
1686  .\"  .\"
1687  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
1688  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
1689  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
1690  instead of one.  instead of one.
1691  .sp  .sp
# Line 1471  a pre-scan of the subject that takes pla Line 1705  a pre-scan of the subject that takes pla
1705  The PCRE_NO_START_OPTIMIZE option disables the start-up optimizations, possibly  The PCRE_NO_START_OPTIMIZE option disables the start-up optimizations, possibly
1706  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
1707  "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)
1708  are considered at every possible starting position in the subject string.  are considered at every possible starting position in the subject string. If
1709    PCRE_NO_START_OPTIMIZE is set at compile time, it cannot be unset at matching
1710    time. The use of PCRE_NO_START_OPTIMIZE disables JIT execution; when it is set,
1711    matching is always done using interpretively.
1712    .P
1713  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.
1714  Consider the pattern  Consider the pattern
1715  .sp  .sp
# Line 1506  string is automatically checked when \fB Line 1744  string is automatically checked when \fB
1744  The value of \fIstartoffset\fP is also checked to ensure that it points to the  The value of \fIstartoffset\fP is also checked to ensure that it points to the
1745  start of a UTF-8 character. There is a discussion about the validity of UTF-8  start of a UTF-8 character. There is a discussion about the validity of UTF-8
1746  strings in the  strings in the
 .\" HTML <a href="pcre.html#utf8strings">  
 .\" </a>  
 section on UTF-8 support  
 .\"  
 in the main  
1747  .\" HREF  .\" HREF
1748  \fBpcre\fP  \fBpcreunicode\fP
1749  .\"  .\"
1750  page. If an invalid UTF-8 sequence of bytes is found, \fBpcre_exec()\fP returns  page. If an invalid sequence of bytes is found, \fBpcre_exec()\fP returns the
1751  the error PCRE_ERROR_BADUTF8. If \fIstartoffset\fP contains a value that does  error PCRE_ERROR_BADUTF8 or, if PCRE_PARTIAL_HARD is set and the problem is a
1752  not point to the start of a UTF-8 character (or to the end of the subject),  truncated character at the end of the subject, PCRE_ERROR_SHORTUTF8. In both
1753  PCRE_ERROR_BADUTF8_OFFSET is returned.  cases, information about the precise nature of the error may also be returned
1754    (see the descriptions of these errors in the section entitled \fIError return
1755    values from\fP \fBpcre_exec()\fP
1756    .\" HTML <a href="#errorlist">
1757    .\" </a>
1758    below).
1759    .\"
1760    If \fIstartoffset\fP contains a value that does not point to the start of a
1761    UTF-8 character (or to the end of the subject), PCRE_ERROR_BADUTF8_OFFSET is
1762    returned.
1763  .P  .P
1764  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
1765  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
1766  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
1767  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
1768  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
1769  the value of \fIstartoffset\fP points to the start of a UTF-8 character (or the  the value of \fIstartoffset\fP points to the start of a character (or the end
1770  end of the subject). When PCRE_NO_UTF8_CHECK is set, the effect of passing an  of the subject). When PCRE_NO_UTF8_CHECK is set, the effect of passing an
1771  invalid UTF-8 string as a subject or an invalid value of \fIstartoffset\fP is  invalid string as a subject or an invalid value of \fIstartoffset\fP is
1772  undefined. Your program may crash.  undefined. Your program may crash.
1773  .sp  .sp
1774    PCRE_PARTIAL_HARD    PCRE_PARTIAL_HARD
# Line 1545  but only if no complete match can be fou Line 1787  but only if no complete match can be fou
1787  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
1788  partial match is found, \fBpcre_exec()\fP immediately returns  partial match is found, \fBpcre_exec()\fP immediately returns
1789  PCRE_ERROR_PARTIAL, without considering any other alternatives. In other words,  PCRE_ERROR_PARTIAL, without considering any other alternatives. In other words,
1790  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
1791  important that an alternative complete match.  important that an alternative complete match.
1792  .P  .P
1793  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 1561  documentation. Line 1803  documentation.
1803  .rs  .rs
1804  .sp  .sp
1805  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
1806  \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
1807  in \fIstartoffset\fP. If this is negative or greater than the length of the  in \fIstartoffset\fP. If this is negative or greater than the length of the
1808  subject, \fBpcre_exec()\fP returns PCRE_ERROR_BADOFFSET.  subject, \fBpcre_exec()\fP returns PCRE_ERROR_BADOFFSET. When the starting
1809  .P  offset is zero, the search for a match starts at the beginning of the subject,
1810  In UTF-8 mode, the byte offset must point to the start of a UTF-8 character (or  and this is by far the most common case. In UTF-8 mode, the byte offset must
1811  the end of the subject). Unlike the pattern string, the subject may contain  point to the start of a UTF-8 character (or the end of the subject). Unlike the
1812  binary zero bytes. When the starting offset is zero, the search for a match  pattern string, the subject may contain binary zero bytes.
 starts at the beginning of the subject, and this is by far the most common  
 case.  
1813  .P  .P
1814  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
1815  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 1598  do this in the Line 1838  do this in the
1838  .\" HREF  .\" HREF
1839  \fBpcredemo\fP  \fBpcredemo\fP
1840  .\"  .\"
1841  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
1842  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
1843  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
1844  instead of one.  instead of one.
1845  .P  .P
# Line 1651  string that it matched that is returned. Line 1891  string that it matched that is returned.
1891  .P  .P
1892  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
1893  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
1894  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
1895  \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
1896  \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
1897  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
1898  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
1899  advisable to supply an \fIovector\fP.  is usually advisable to supply an \fIovector\fP of reasonable size.
1900    .P
1901    There are some cases where zero is returned (indicating vector overflow) when
1902    in fact the vector is exactly the right size for the final match. For example,
1903    consider the pattern
1904    .sp
1905      (a)(?:(b)c|bd)
1906    .sp
1907    If a vector of 6 elements (allowing for only 1 captured substring) is given
1908    with subject string "abd", \fBpcre_exec()\fP will try to set the second
1909    captured string, thereby recording a vector overflow, before failing to match
1910    "c" and backing up to try the second alternative. The zero return, however,
1911    does correctly indicate that the maximum number of slots (namely 2) have been
1912    filled. In similar cases where there is temporary overflow, but the final
1913    number of used slots is actually less than the maximum, a non-zero value is
1914    returned.
1915  .P  .P
1916  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
1917  subpatterns there are in a compiled pattern. The smallest size for  subpatterns there are in a compiled pattern. The smallest size for
# Line 1677  return from the function is 2, because t Line 1932  return from the function is 2, because t
1932  number is 1, and the offsets for for the second and third capturing subpatterns  number is 1, and the offsets for for the second and third capturing subpatterns
1933  (assuming the vector is large enough, of course) are set to -1.  (assuming the vector is large enough, of course) are set to -1.
1934  .P  .P
1935  \fBNote\fP: Elements of \fIovector\fP that do not correspond to capturing  \fBNote\fP: Elements in the first two-thirds of \fIovector\fP that do not
1936  parentheses in the pattern are never changed. That is, if a pattern contains  correspond to capturing parentheses in the pattern are never changed. That is,
1937  \fIn\fP capturing parentheses, no more than \fIovector[0]\fP to  if a pattern contains \fIn\fP capturing parentheses, no more than
1938  \fIovector[2n+1]\fP are set by \fBpcre_exec()\fP. The other elements retain  \fIovector[0]\fP to \fIovector[2n+1]\fP are set by \fBpcre_exec()\fP. The other
1939  whatever values they previously had.  elements (in the first two-thirds) retain whatever values they previously had.
1940  .P  .P
1941  Some convenience functions are provided for extracting the captured substrings  Some convenience functions are provided for extracting the captured substrings
1942  as separate strings. These are described below.  as separate strings. These are described below.
1943  .  .
1944    .
1945  .\" HTML <a name="errorlist"></a>  .\" HTML <a name="errorlist"></a>
1946  .SS "Error return values from \fBpcre_exec()\fP"  .SS "Error return values from \fBpcre_exec()\fP"
1947  .rs  .rs
# Line 1755  documentation for details. Line 2011  documentation for details.
2011  .sp  .sp
2012    PCRE_ERROR_BADUTF8        (-10)    PCRE_ERROR_BADUTF8        (-10)
2013  .sp  .sp
2014  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,
2015    and the PCRE_NO_UTF8_CHECK option was not set. If the size of the output vector
2016    (\fIovecsize\fP) is at least 2, the byte offset to the start of the the invalid
2017    UTF-8 character is placed in the first element, and a reason code is placed in
2018    the second element. The reason codes are listed in the
2019    .\" HTML <a href="#badutf8reasons">
2020    .\" </a>
2021    following section.
2022    .\"
2023    For backward compatibility, if PCRE_PARTIAL_HARD is set and the problem is a
2024    truncated UTF-8 character at the end of the subject (reason codes 1 to 5),
2025    PCRE_ERROR_SHORTUTF8 is returned instead of PCRE_ERROR_BADUTF8.
2026  .sp  .sp
2027    PCRE_ERROR_BADUTF8_OFFSET (-11)    PCRE_ERROR_BADUTF8_OFFSET (-11)
2028  .sp  .sp
2029  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
2030  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
2031    \fIstartoffset\fP did not point to the beginning of a UTF-8 character or the
2032    end of the subject.
2033  .sp  .sp
2034    PCRE_ERROR_PARTIAL        (-12)    PCRE_ERROR_PARTIAL        (-12)
2035  .sp  .sp
# Line 1798  An invalid combination of PCRE_NEWLINE_\ Line 2067  An invalid combination of PCRE_NEWLINE_\
2067  .sp  .sp
2068    PCRE_ERROR_BADOFFSET      (-24)    PCRE_ERROR_BADOFFSET      (-24)
2069  .sp  .sp
2070  The value of \fIstartoffset\fP was negative or greater than the length of the  The value of \fIstartoffset\fP was negative or greater than the length of the
2071  subject, that is, the value in \fIlength\fP.  subject, that is, the value in \fIlength\fP.
2072    .sp
2073      PCRE_ERROR_SHORTUTF8      (-25)
2074    .sp
2075    This error is returned instead of PCRE_ERROR_BADUTF8 when the subject string
2076    ends with a truncated UTF-8 character and the PCRE_PARTIAL_HARD option is set.
2077    Information about the failure is returned as for PCRE_ERROR_BADUTF8. It is in
2078    fact sufficient to detect this case, but this special error code for
2079    PCRE_PARTIAL_HARD precedes the implementation of returned information; it is
2080    retained for backwards compatibility.
2081    .sp
2082      PCRE_ERROR_RECURSELOOP    (-26)
2083    .sp
2084    This error is returned when \fBpcre_exec()\fP detects a recursion loop within
2085    the pattern. Specifically, it means that either the whole pattern or a
2086    subpattern has been called recursively for the second time at the same position
2087    in the subject string. Some simple patterns that might do this are detected and
2088    faulted at compile time, but more complicated cases, in particular mutual
2089    recursions between two different subpatterns, cannot be detected until run
2090    time.
2091    .sp
2092      PCRE_ERROR_JIT_STACKLIMIT (-27)
2093    .sp
2094    This error is returned when a pattern that was successfully studied using a
2095    JIT compile option is being matched, but the memory available for the
2096    just-in-time processing stack is not large enough. See the
2097    .\" HREF
2098    \fBpcrejit\fP
2099    .\"
2100    documentation for more details.
2101    .sp
2102      PCRE_ERROR_BADMODE (-28)
2103    .sp
2104    This error is given if a pattern that was compiled by the 8-bit library is
2105    passed to a 16-bit library function, or vice versa.
2106    .sp
2107      PCRE_ERROR_BADENDIANNESS (-29)
2108    .sp
2109    This error is given if a pattern that was compiled and saved is reloaded on a
2110    host with different endianness. The utility function
2111    \fBpcre_pattern_to_host_byte_order()\fP can be used to convert such a pattern
2112    so that it runs on the new host.
2113  .P  .P
2114  Error numbers -16 to -20 and -22 are not used by \fBpcre_exec()\fP.  Error numbers -16 to -20 and -22 are not used by \fBpcre_exec()\fP.
2115  .  .
2116  .  .
2117    .\" HTML <a name="badutf8reasons"></a>
2118    .SS "Reason codes for invalid UTF-8 strings"
2119    .rs
2120    .sp
2121    This section applies only to the 8-bit library. The corresponding information
2122    for the 16-bit library is given in the
2123    .\" HREF
2124    \fBpcre16\fP
2125    .\"
2126    page.
2127    .P
2128    When \fBpcre_exec()\fP returns either PCRE_ERROR_BADUTF8 or
2129    PCRE_ERROR_SHORTUTF8, and the size of the output vector (\fIovecsize\fP) is at
2130    least 2, the offset of the start of the invalid UTF-8 character is placed in
2131    the first output vector element (\fIovector[0]\fP) and a reason code is placed
2132    in the second element (\fIovector[1]\fP). The reason codes are given names in
2133    the \fBpcre.h\fP header file:
2134    .sp
2135      PCRE_UTF8_ERR1
2136      PCRE_UTF8_ERR2
2137      PCRE_UTF8_ERR3
2138      PCRE_UTF8_ERR4
2139      PCRE_UTF8_ERR5
2140    .sp
2141    The string ends with a truncated UTF-8 character; the code specifies how many
2142    bytes are missing (1 to 5). Although RFC 3629 restricts UTF-8 characters to be
2143    no longer than 4 bytes, the encoding scheme (originally defined by RFC 2279)
2144    allows for up to 6 bytes, and this is checked first; hence the possibility of
2145    4 or 5 missing bytes.
2146    .sp
2147      PCRE_UTF8_ERR6
2148      PCRE_UTF8_ERR7
2149      PCRE_UTF8_ERR8
2150      PCRE_UTF8_ERR9
2151      PCRE_UTF8_ERR10
2152    .sp
2153    The two most significant bits of the 2nd, 3rd, 4th, 5th, or 6th byte of the
2154    character do not have the binary value 0b10 (that is, either the most
2155    significant bit is 0, or the next bit is 1).
2156    .sp
2157      PCRE_UTF8_ERR11
2158      PCRE_UTF8_ERR12
2159    .sp
2160    A character that is valid by the RFC 2279 rules is either 5 or 6 bytes long;
2161    these code points are excluded by RFC 3629.
2162    .sp
2163      PCRE_UTF8_ERR13
2164    .sp
2165    A 4-byte character has a value greater than 0x10fff; these code points are
2166    excluded by RFC 3629.
2167    .sp
2168      PCRE_UTF8_ERR14
2169    .sp
2170    A 3-byte character has a value in the range 0xd800 to 0xdfff; this range of
2171    code points are reserved by RFC 3629 for use with UTF-16, and so are excluded
2172    from UTF-8.
2173    .sp
2174      PCRE_UTF8_ERR15
2175      PCRE_UTF8_ERR16
2176      PCRE_UTF8_ERR17
2177      PCRE_UTF8_ERR18
2178      PCRE_UTF8_ERR19
2179    .sp
2180    A 2-, 3-, 4-, 5-, or 6-byte character is "overlong", that is, it codes for a
2181    value that can be represented by fewer bytes, which is invalid. For example,
2182    the two bytes 0xc0, 0xae give the value 0x2e, whose correct coding uses just
2183    one byte.
2184    .sp
2185      PCRE_UTF8_ERR20
2186    .sp
2187    The two most significant bits of the first byte of a character have the binary
2188    value 0b10 (that is, the most significant bit is 1 and the second is 0). Such a
2189    byte can only validly occur as the second or subsequent byte of a multi-byte
2190    character.
2191    .sp
2192      PCRE_UTF8_ERR21
2193    .sp
2194    The first byte of a character has the value 0xfe or 0xff. These values can
2195    never occur in a valid UTF-8 string.
2196    .
2197    .
2198  .SH "EXTRACTING CAPTURED SUBSTRINGS BY NUMBER"  .SH "EXTRACTING CAPTURED SUBSTRINGS BY NUMBER"
2199  .rs  .rs
2200  .sp  .sp
# Line 1966  names are not included in the compiled c Line 2357  names are not included in the compiled c
2357  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
2358  same number causes an error at compile time.  same number causes an error at compile time.
2359  .  .
2360    .
2361  .SH "DUPLICATE SUBPATTERN NAMES"  .SH "DUPLICATE SUBPATTERN NAMES"
2362  .rs  .rs
2363  .sp  .sp
# Line 1999  fourth are pointers to variables which a Line 2391  fourth are pointers to variables which a
2391  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
2392  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
2393  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
2394  described above in the section entitled \fIInformation about a pattern\fP.  described above in the section entitled \fIInformation about a pattern\fP
2395    .\" HTML <a href="#infoaboutpattern">
2396    .\" </a>
2397    above.
2398    .\"
2399  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
2400  numbers, and hence the captured data, if any.  numbers, and hence the captured data, if any.
2401  .  .
# Line 2026  other alternatives. Ultimately, when it Line 2422  other alternatives. Ultimately, when it
2422  will yield PCRE_ERROR_NOMATCH.  will yield PCRE_ERROR_NOMATCH.
2423  .  .
2424  .  .
2425    .SH "OBTAINING AN ESTIMATE OF STACK USAGE"
2426    .rs
2427    .sp
2428    Matching certain patterns using \fBpcre_exec()\fP can use a lot of process
2429    stack, which in certain environments can be rather limited in size. Some users
2430    find it helpful to have an estimate of the amount of stack that is used by
2431    \fBpcre_exec()\fP, to help them set recursion limits, as described in the
2432    .\" HREF
2433    \fBpcrestack\fP
2434    .\"
2435    documentation. The estimate that is output by \fBpcretest\fP when called with
2436    the \fB-m\fP and \fB-C\fP options is obtained by calling \fBpcre_exec\fP with
2437    the values NULL, NULL, NULL, -999, and -999 for its first five arguments.
2438    .P
2439    Normally, if its first argument is NULL, \fBpcre_exec()\fP immediately returns
2440    the negative error code PCRE_ERROR_NULL, but with this special combination of
2441    arguments, it returns instead a negative number whose absolute value is the
2442    approximate stack frame size in bytes. (A negative number is used so that it is
2443    clear that no match has happened.) The value is approximate because in some
2444    cases, recursive calls to \fBpcre_exec()\fP occur when there are one or two
2445    additional variables on the stack.
2446    .P
2447    If PCRE has been compiled to use the heap instead of the stack for recursion,
2448    the value returned is the size of each block that is obtained from the heap.
2449    .
2450    .
2451  .\" HTML <a name="dfamatch"></a>  .\" HTML <a name="dfamatch"></a>
2452  .SH "MATCHING A PATTERN: THE ALTERNATIVE FUNCTION"  .SH "MATCHING A PATTERN: THE ALTERNATIVE FUNCTION"
2453  .rs  .rs
# Line 2129  match. There is more discussion of this Line 2551  match. There is more discussion of this
2551  .\"  .\"
2552  documentation.  documentation.
2553  .  .
2554    .
2555  .SS "Successful returns from \fBpcre_dfa_exec()\fP"  .SS "Successful returns from \fBpcre_dfa_exec()\fP"
2556  .rs  .rs
2557  .sp  .sp
# Line 2160  returns data, even though the meaning of Line 2583  returns data, even though the meaning of
2583  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
2584  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
2585  \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
2586  the longest matches.  the longest matches. Unlike \fBpcre_exec()\fP, \fBpcre_dfa_exec()\fP can use
2587    the entire \fIovector\fP for returning matched strings.
2588    .
2589  .  .
2590  .SS "Error returns from \fBpcre_dfa_exec()\fP"  .SS "Error returns from \fBpcre_dfa_exec()\fP"
2591  .rs  .rs
# Line 2189  group. These are not supported. Line 2614  group. These are not supported.
2614    PCRE_ERROR_DFA_UMLIMIT    (-18)    PCRE_ERROR_DFA_UMLIMIT    (-18)
2615  .sp  .sp
2616  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
2617  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
2618  supported (it is meaningless).  \fImatch_limit_recursion\fP fields. This is not supported (these fields are
2619    meaningless for DFA matching).
2620  .sp  .sp
2621    PCRE_ERROR_DFA_WSSIZE     (-19)    PCRE_ERROR_DFA_WSSIZE     (-19)
2622  .sp  .sp
# Line 2208  extremely rare, as a vector of size 1000 Line 2634  extremely rare, as a vector of size 1000
2634  .SH "SEE ALSO"  .SH "SEE ALSO"
2635  .rs  .rs
2636  .sp  .sp
2637  \fBpcrebuild\fP(3), \fBpcrecallout\fP(3), \fBpcrecpp(3)\fP(3),  \fBpcre16\fP(3), \fBpcrebuild\fP(3), \fBpcrecallout\fP(3), \fBpcrecpp(3)\fP(3),
2638  \fBpcrematching\fP(3), \fBpcrepartial\fP(3), \fBpcreposix\fP(3),  \fBpcrematching\fP(3), \fBpcrepartial\fP(3), \fBpcreposix\fP(3),
2639  \fBpcreprecompile\fP(3), \fBpcresample\fP(3), \fBpcrestack\fP(3).  \fBpcreprecompile\fP(3), \fBpcresample\fP(3), \fBpcrestack\fP(3).
2640  .  .
# Line 2227  Cambridge CB2 3QH, England. Line 2653  Cambridge CB2 3QH, England.
2653  .rs  .rs
2654  .sp  .sp
2655  .nf  .nf
2656  Last updated: 06 November 2010  Last updated: 24 February 2012
2657  Copyright (c) 1997-2010 University of Cambridge.  Copyright (c) 1997-2012 University of Cambridge.
2658  .fi  .fi

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