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1  .TH PCREAPI 3  .TH PCREAPI 3 "31 October 2012" "PCRE 8.32"
2  .SH NAME  .SH NAME
3  PCRE - Perl-compatible regular expressions  PCRE - Perl-compatible regular expressions
4  .sp  .sp
# Line 95  PCRE - Perl-compatible regular expressio Line 95  PCRE - Perl-compatible regular expressio
95  .SH "PCRE NATIVE API AUXILIARY FUNCTIONS"  .SH "PCRE NATIVE API AUXILIARY FUNCTIONS"
96  .rs  .rs
97  .sp  .sp
98    .B int pcre_jit_exec(const pcre *\fIcode\fP, "const pcre_extra *\fIextra\fP,"
99    .ti +5n
100    .B "const char *\fIsubject\fP," int \fIlength\fP, int \fIstartoffset\fP,
101    .ti +5n
102    .B int \fIoptions\fP, int *\fIovector\fP, int \fIovecsize\fP,
103    .ti +5n
104    .B pcre_jit_stack *\fIjstack\fP);
105    .PP
106  .B pcre_jit_stack *pcre_jit_stack_alloc(int \fIstartsize\fP, int \fImaxsize\fP);  .B pcre_jit_stack *pcre_jit_stack_alloc(int \fIstartsize\fP, int \fImaxsize\fP);
107  .PP  .PP
108  .B void pcre_jit_stack_free(pcre_jit_stack *\fIstack\fP);  .B void pcre_jit_stack_free(pcre_jit_stack *\fIstack\fP);
# Line 134  PCRE - Perl-compatible regular expressio Line 142  PCRE - Perl-compatible regular expressio
142  .B int (*pcre_callout)(pcre_callout_block *);  .B int (*pcre_callout)(pcre_callout_block *);
143  .  .
144  .  .
145  .SH "PCRE 8-BIT AND 16-BIT LIBRARIES"  .SH "PCRE 8-BIT, 16-BIT AND 32-BIT LIBRARIES"
146  .rs  .rs
147  .sp  .sp
148  From release 8.30, PCRE can be compiled as a library for handling 16-bit  From release 8.30, PCRE can be compiled as a library for handling 16-bit
149  character strings as well as, or instead of, the original library that handles  character strings as well as, or instead of, the original library that handles
150  8-bit character strings. To avoid too much complication, this document  8-bit character strings. From release 8.32, PCRE can also be compiled as a
151  describes the 8-bit versions of the functions, with only occasional references  library for handling 32-bit character strings. To avoid too much complication,
152  to the 16-bit library.  this document describes the 8-bit versions of the functions, with only
153  .P  occasional references to the 16-bit and 32-bit libraries.
154  The 16-bit functions operate in the same way as their 8-bit counterparts; they  .P
155  just use different data types for their arguments and results, and their names  The 16-bit and 32-bit functions operate in the same way as their 8-bit
156  start with \fBpcre16_\fP instead of \fBpcre_\fP. For every option that has UTF8  counterparts; they just use different data types for their arguments and
157  in its name (for example, PCRE_UTF8), there is a corresponding 16-bit name with  results, and their names start with \fBpcre16_\fP or \fBpcre32_\fP instead of
158  UTF8 replaced by UTF16. This facility is in fact just cosmetic; the 16-bit  \fBpcre_\fP. For every option that has UTF8 in its name (for example,
159  option names define the same bit values.  PCRE_UTF8), there are corresponding 16-bit and 32-bit names with UTF8 replaced
160    by UTF16 or UTF32, respectively. This facility is in fact just cosmetic; the
161    16-bit and 32-bit option names define the same bit values.
162  .P  .P
163  References to bytes and UTF-8 in this document should be read as references to  References to bytes and UTF-8 in this document should be read as references to
164  16-bit data quantities and UTF-16 when using the 16-bit library, unless  16-bit data quantities and UTF-16 when using the 16-bit library, or 32-bit data
165  specified otherwise. More details of the specific differences for the 16-bit  quantities and UTF-32 when using the 32-bit library, unless specified
166  library are given in the  otherwise. More details of the specific differences for the 16-bit and 32-bit
167    libraries are given in the
168  .\" HREF  .\" HREF
169  \fBpcre16\fP  \fBpcre16\fP
170  .\"  .\"
171  page.  and
172    .\" HREF
173    \fBpcre32\fP
174    .\"
175    pages.
176  .  .
177  .  .
178  .SH "PCRE API OVERVIEW"  .SH "PCRE API OVERVIEW"
# Line 213  used if available, by setting an option Line 228  used if available, by setting an option
228  relevant. More complicated programs might need to make use of the functions  relevant. More complicated programs might need to make use of the functions
229  \fBpcre_jit_stack_alloc()\fP, \fBpcre_jit_stack_free()\fP, and  \fBpcre_jit_stack_alloc()\fP, \fBpcre_jit_stack_free()\fP, and
230  \fBpcre_assign_jit_stack()\fP in order to control the JIT code's memory usage.  \fBpcre_assign_jit_stack()\fP in order to control the JIT code's memory usage.
231  These functions are discussed in the  .P
232    From release 8.32 there is also a direct interface for JIT execution, which
233    gives improved performance. The JIT-specific functions are discussed in the
234  .\" HREF  .\" HREF
235  \fBpcrejit\fP  \fBpcrejit\fP
236  .\"  .\"
# Line 302  PCRE supports five different conventions Line 319  PCRE supports five different conventions
319  strings: a single CR (carriage return) character, a single LF (linefeed)  strings: a single CR (carriage return) character, a single LF (linefeed)
320  character, the two-character sequence CRLF, any of the three preceding, or any  character, the two-character sequence CRLF, any of the three preceding, or any
321  Unicode newline sequence. The Unicode newline sequences are the three just  Unicode newline sequence. The Unicode newline sequences are the three just
322  mentioned, plus the single characters VT (vertical tab, U+000B), FF (formfeed,  mentioned, plus the single characters VT (vertical tab, U+000B), FF (form feed,
323  U+000C), NEL (next line, U+0085), LS (line separator, U+2028), and PS  U+000C), NEL (next line, U+0085), LS (line separator, U+2028), and PS
324  (paragraph separator, U+2029).  (paragraph separator, U+2029).
325  .P  .P
# Line 392  not recognized. The following informatio Line 409  not recognized. The following informatio
409    PCRE_CONFIG_UTF8    PCRE_CONFIG_UTF8
410  .sp  .sp
411  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;
412  otherwise it is set to zero. If this option is given to the 16-bit version of  otherwise it is set to zero. This value should normally be given to the 8-bit
413  this function, \fBpcre16_config()\fP, the result is PCRE_ERROR_BADOPTION.  version of this function, \fBpcre_config()\fP. If it is given to the 16-bit
414    or 32-bit version of this function, the result is PCRE_ERROR_BADOPTION.
415  .sp  .sp
416    PCRE_CONFIG_UTF16    PCRE_CONFIG_UTF16
417  .sp  .sp
418  The output is an integer that is set to one if UTF-16 support is available;  The output is an integer that is set to one if UTF-16 support is available;
419  otherwise it is set to zero. This value should normally be given to the 16-bit  otherwise it is set to zero. This value should normally be given to the 16-bit
420  version of this function, \fBpcre16_config()\fP. If it is given to the 8-bit  version of this function, \fBpcre16_config()\fP. If it is given to the 8-bit
421  version of this function, the result is PCRE_ERROR_BADOPTION.  or 32-bit version of this function, the result is PCRE_ERROR_BADOPTION.
422    .sp
423      PCRE_CONFIG_UTF32
424    .sp
425    The output is an integer that is set to one if UTF-32 support is available;
426    otherwise it is set to zero. This value should normally be given to the 32-bit
427    version of this function, \fBpcre32_config()\fP. If it is given to the 8-bit
428    or 16-bit version of this function, the result is PCRE_ERROR_BADOPTION.
429  .sp  .sp
430    PCRE_CONFIG_UNICODE_PROPERTIES    PCRE_CONFIG_UNICODE_PROPERTIES
431  .sp  .sp
# Line 415  compiling is available; otherwise it is Line 440  compiling is available; otherwise it is
440    PCRE_CONFIG_JITTARGET    PCRE_CONFIG_JITTARGET
441  .sp  .sp
442  The output is a pointer to a zero-terminated "const char *" string. If JIT  The output is a pointer to a zero-terminated "const char *" string. If JIT
443  support is available, the string contains the name of the architecture for  support is available, the string contains the name of the architecture for
444  which the JIT compiler is configured, for example "x86 32bit (little endian +  which the JIT compiler is configured, for example "x86 32bit (little endian +
445  unaligned)". If JIT support is not available, the result is NULL.  unaligned)". If JIT support is not available, the result is NULL.
446  .sp  .sp
447    PCRE_CONFIG_NEWLINE    PCRE_CONFIG_NEWLINE
448  .sp  .sp
449  The output is an integer whose value specifies the default character sequence  The output is an integer whose value specifies the default character sequence
450  that is recognized as meaning "newline". The four values that are supported  that is recognized as meaning "newline". The values that are supported in
451  are: 10 for LF, 13 for CR, 3338 for CRLF, -2 for ANYCRLF, and -1 for ANY.  ASCII/Unicode environments are: 10 for LF, 13 for CR, 3338 for CRLF, -2 for
452  Though they are derived from ASCII, the same values are returned in EBCDIC  ANYCRLF, and -1 for ANY. In EBCDIC environments, CR, ANYCRLF, and ANY yield the
453  environments. The default should normally correspond to the standard sequence  same values. However, the value for LF is normally 21, though some EBCDIC
454  for your operating system.  environments use 37. The corresponding values for CRLF are 3349 and 3365. The
455    default should normally correspond to the standard sequence for your operating
456    system.
457  .sp  .sp
458    PCRE_CONFIG_BSR    PCRE_CONFIG_BSR
459  .sp  .sp
# Line 440  or CRLF. The default can be overridden w Line 467  or CRLF. The default can be overridden w
467  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
468  linkage in compiled regular expressions. For the 8-bit library, the value can  linkage in compiled regular expressions. For the 8-bit library, the value can
469  be 2, 3, or 4. For the 16-bit library, the value is either 2 or 4 and is still  be 2, 3, or 4. For the 16-bit library, the value is either 2 or 4 and is still
470  a number of bytes. The default value of 2 is sufficient for all but the most  a number of bytes. For the 32-bit library, the value is either 2 or 4 and is
471  massive patterns, since it allows the compiled pattern to be up to 64K in size.  still a number of bytes. The default value of 2 is sufficient for all but the
472  Larger values allow larger regular expressions to be compiled, at the expense  most massive patterns, since it allows the compiled pattern to be up to 64K in
473  of slower matching.  size. Larger values allow larger regular expressions to be compiled, at the
474    expense of slower matching.
475  .sp  .sp
476    PCRE_CONFIG_POSIX_MALLOC_THRESHOLD    PCRE_CONFIG_POSIX_MALLOC_THRESHOLD
477  .sp  .sp
# Line 526  documentation). For those options that c Line 554  documentation). For those options that c
554  the pattern, the contents of the \fIoptions\fP argument specifies their  the pattern, the contents of the \fIoptions\fP argument specifies their
555  settings at the start of compilation and execution. The PCRE_ANCHORED,  settings at the start of compilation and execution. The PCRE_ANCHORED,
556  PCRE_BSR_\fIxxx\fP, PCRE_NEWLINE_\fIxxx\fP, PCRE_NO_UTF8_CHECK, and  PCRE_BSR_\fIxxx\fP, PCRE_NEWLINE_\fIxxx\fP, PCRE_NO_UTF8_CHECK, and
557  PCRE_NO_START_OPT options can be set at the time of matching as well as at  PCRE_NO_START_OPTIMIZE options can be set at the time of matching as well as at
558  compile time.  compile time.
559  .P  .P
560  If \fIerrptr\fP is NULL, \fBpcre_compile()\fP returns NULL immediately.  If \fIerrptr\fP is NULL, \fBpcre_compile()\fP returns NULL immediately.
# Line 642  documentation. Line 670  documentation.
670  .sp  .sp
671    PCRE_EXTENDED    PCRE_EXTENDED
672  .sp  .sp
673  If this bit is set, whitespace data characters in the pattern are totally  If this bit is set, white space data characters in the pattern are totally
674  ignored except when escaped or inside a character class. Whitespace does not  ignored except when escaped or inside a character class. White space does not
675  include the VT character (code 11). In addition, characters between an  include the VT character (code 11). In addition, characters between an
676  unescaped # outside a character class and the next newline, inclusive, are also  unescaped # outside a character class and the next newline, inclusive, are also
677  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
# Line 661  comment is a literal newline sequence in Line 689  comment is a literal newline sequence in
689  happen to represent a newline do not count.  happen to represent a newline do not count.
690  .P  .P
691  This option makes it possible to include comments inside complicated patterns.  This option makes it possible to include comments inside complicated patterns.
692  Note, however, that this applies only to data characters. Whitespace characters  Note, however, that this applies only to data characters. White space characters
693  may never appear within special character sequences in a pattern, for example  may never appear within special character sequences in a pattern, for example
694  within the sequence (?( that introduces a conditional subpattern.  within the sequence (?( that introduces a conditional subpattern.
695  .sp  .sp
# Line 739  indicated by a single character (CR or L Line 767  indicated by a single character (CR or L
767  PCRE_NEWLINE_CRLF specifies that a newline is indicated by the two-character  PCRE_NEWLINE_CRLF specifies that a newline is indicated by the two-character
768  CRLF sequence. Setting PCRE_NEWLINE_ANYCRLF specifies that any of the three  CRLF sequence. Setting PCRE_NEWLINE_ANYCRLF specifies that any of the three
769  preceding sequences should be recognized. Setting PCRE_NEWLINE_ANY specifies  preceding sequences should be recognized. Setting PCRE_NEWLINE_ANY specifies
770  that any Unicode newline sequence should be recognized. The Unicode newline  that any Unicode newline sequence should be recognized.
771  sequences are the three just mentioned, plus the single characters VT (vertical  .P
772  tab, U+000B), FF (formfeed, U+000C), NEL (next line, U+0085), LS (line  In an ASCII/Unicode environment, the Unicode newline sequences are the three
773  separator, U+2028), and PS (paragraph separator, U+2029). For the 8-bit  just mentioned, plus the single characters VT (vertical tab, U+000B), FF (form
774  library, the last two are recognized only in UTF-8 mode.  feed, U+000C), NEL (next line, U+0085), LS (line separator, U+2028), and PS
775    (paragraph separator, U+2029). For the 8-bit library, the last two are
776    recognized only in UTF-8 mode.
777    .P
778    When PCRE is compiled to run in an EBCDIC (mainframe) environment, the code for
779    CR is 0x0d, the same as ASCII. However, the character code for LF is normally
780    0x15, though in some EBCDIC environments 0x25 is used. Whichever of these is
781    not LF is made to correspond to Unicode's NEL character. EBCDIC codes are all
782    less than 256. For more details, see the
783    .\" HREF
784    \fBpcrebuild\fP
785    .\"
786    documentation.
787  .P  .P
788  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
789  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 753  PCRE_NEWLINE_CR with PCRE_NEWLINE_LF is Line 793  PCRE_NEWLINE_CR with PCRE_NEWLINE_LF is
793  other combinations may yield unused numbers and cause an error.  other combinations may yield unused numbers and cause an error.
794  .P  .P
795  The only time that a line break in a pattern is specially recognized when  The only time that a line break in a pattern is specially recognized when
796  compiling is when PCRE_EXTENDED is set. CR and LF are whitespace characters,  compiling is when PCRE_EXTENDED is set. CR and LF are white space characters,
797  and so are ignored in this mode. Also, an unescaped # outside a character class  and so are ignored in this mode. Also, an unescaped # outside a character class
798  indicates a comment that lasts until after the next line break sequence. In  indicates a comment that lasts until after the next line break sequence. In
799  other circumstances, line break sequences in patterns are treated as literal  other circumstances, line break sequences in patterns are treated as literal
# Line 819  page. Line 859  page.
859  .sp  .sp
860    PCRE_NO_UTF8_CHECK    PCRE_NO_UTF8_CHECK
861  .sp  .sp
862  When PCRE_UTF8 is set, the validity of the pattern as a UTF-8  When PCRE_UTF8 is set, the validity of the pattern as a UTF-8 string is
863  string is automatically checked. There is a discussion about the  automatically checked. There is a discussion about the
864  .\" HTML <a href="pcreunicode.html#utf8strings">  .\" HTML <a href="pcreunicode.html#utf8strings">
865  .\" </a>  .\" </a>
866  validity of UTF-8 strings  validity of UTF-8 strings
867  .\"  .\"
868  in the  in the
869  .\" HREF  .\" HREF
# Line 835  this check for performance reasons, you Line 875  this check for performance reasons, you
875  When it is set, the effect of passing an invalid UTF-8 string as a pattern is  When it is set, the effect of passing an invalid UTF-8 string as a pattern is
876  undefined. It may cause your program to crash. Note that this option can also  undefined. It may cause your program to crash. Note that this option can also
877  be passed to \fBpcre_exec()\fP and \fBpcre_dfa_exec()\fP, to suppress the  be passed to \fBpcre_exec()\fP and \fBpcre_dfa_exec()\fP, to suppress the
878  validity checking of subject strings.  validity checking of subject strings only. If the same string is being matched
879    many times, the option can be safely set for the second and subsequent
880    matchings to improve performance.
881  .  .
882  .  .
883  .SH "COMPILATION ERROR CODES"  .SH "COMPILATION ERROR CODES"
# Line 843  validity checking of subject strings. Line 885  validity checking of subject strings.
885  .sp  .sp
886  The following table lists the error codes than may be returned by  The following table lists the error codes than may be returned by
887  \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
888  both compiling functions. Note that error messages are always 8-bit ASCII  both compiling functions. Note that error messages are always 8-bit ASCII
889  strings, even in 16-bit mode. As PCRE has developed, some error codes have  strings, even in 16-bit or 32-bit mode. As PCRE has developed, some error codes
890  fallen out of use. To avoid confusion, they have not been re-used.  have fallen out of use. To avoid confusion, they have not been re-used.
891  .sp  .sp
892     0  no error     0  no error
893     1  \e at end of pattern     1  \e at end of pattern
# Line 917  fallen out of use. To avoid confusion, t Line 959  fallen out of use. To avoid confusion, t
959    65  different names for subpatterns of the same number are    65  different names for subpatterns of the same number are
960          not allowed          not allowed
961    66  (*MARK) must have an argument    66  (*MARK) must have an argument
962    67  this version of PCRE is not compiled with Unicode property    67  this version of PCRE is not compiled with Unicode property
963          support          support
964    68  \ec must be followed by an ASCII character    68  \ec must be followed by an ASCII character
965    69  \ek is not followed by a braced, angle-bracketed, or quoted name    69  \ek is not followed by a braced, angle-bracketed, or quoted name
966    70  internal error: unknown opcode in find_fixedlength()    70  internal error: unknown opcode in find_fixedlength()
967    71  \eN is not supported in a class    71  \eN is not supported in a class
968    72  too many forward references    72  too many forward references
969    73  disallowed Unicode code point (>= 0xd800 && <= 0xdfff)    73  disallowed Unicode code point (>= 0xd800 && <= 0xdfff)
970    74  invalid UTF-16 string (specifically UTF-16)    74  invalid UTF-16 string (specifically UTF-16)
971      75  name is too long in (*MARK), (*PRUNE), (*SKIP), or (*THEN)
972      76  character value in \eu.... sequence is too large
973      77  invalid UTF-32 string (specifically UTF-32)
974  .sp  .sp
975  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
976  be used if the limits were changed when PCRE was built.  be used if the limits were changed when PCRE was built.
# Line 958  below Line 1003  below
1003  in the section on matching a pattern.  in the section on matching a pattern.
1004  .P  .P
1005  If studying the pattern does not produce any useful information,  If studying the pattern does not produce any useful information,
1006  \fBpcre_study()\fP returns NULL. In that circumstance, if the calling program  \fBpcre_study()\fP returns NULL by default. In that circumstance, if the
1007  wants to pass any of the other fields to \fBpcre_exec()\fP or  calling program wants to pass any of the other fields to \fBpcre_exec()\fP or
1008  \fBpcre_dfa_exec()\fP, it must set up its own \fBpcre_extra\fP block.  \fBpcre_dfa_exec()\fP, it must set up its own \fBpcre_extra\fP block. However,
1009  .P  if \fBpcre_study()\fP is called with the PCRE_STUDY_EXTRA_NEEDED option, it
1010  The second argument of \fBpcre_study()\fP contains option bits. There is only  returns a \fBpcre_extra\fP block even if studying did not find any additional
1011  one option: PCRE_STUDY_JIT_COMPILE. If this is set, and the just-in-time  information. It may still return NULL, however, if an error occurs in
1012  compiler is available, the pattern is further compiled into machine code that  \fBpcre_study()\fP.
1013  executes much faster than the \fBpcre_exec()\fP matching function. If  .P
1014  the just-in-time compiler is not available, this option is ignored. All other  The second argument of \fBpcre_study()\fP contains option bits. There are three
1015  bits in the \fIoptions\fP argument must be zero.  further options in addition to PCRE_STUDY_EXTRA_NEEDED:
1016    .sp
1017      PCRE_STUDY_JIT_COMPILE
1018      PCRE_STUDY_JIT_PARTIAL_HARD_COMPILE
1019      PCRE_STUDY_JIT_PARTIAL_SOFT_COMPILE
1020    .sp
1021    If any of these are set, and the just-in-time compiler is available, the
1022    pattern is further compiled into machine code that executes much faster than
1023    the \fBpcre_exec()\fP interpretive matching function. If the just-in-time
1024    compiler is not available, these options are ignored. All undefined bits in the
1025    \fIoptions\fP argument must be zero.
1026  .P  .P
1027  JIT compilation is a heavyweight optimization. It can take some time for  JIT compilation is a heavyweight optimization. It can take some time for
1028  patterns to be analyzed, and for one-off matches and simple patterns the  patterns to be analyzed, and for one-off matches and simple patterns the
# Line 991  When you are finished with a pattern, yo Line 1046  When you are finished with a pattern, yo
1046  study data by calling \fBpcre_free_study()\fP. This function was added to the  study data by calling \fBpcre_free_study()\fP. This function was added to the
1047  API for release 8.20. For earlier versions, the memory could be freed with  API for release 8.20. For earlier versions, the memory could be freed with
1048  \fBpcre_free()\fP, just like the pattern itself. This will still work in cases  \fBpcre_free()\fP, just like the pattern itself. This will still work in cases
1049  where PCRE_STUDY_JIT_COMPILE is not used, but it is advisable to change to the  where JIT optimization is not used, but it is advisable to change to the new
1050  new function when convenient.  function when convenient.
1051  .P  .P
1052  This is a typical way in which \fBpcre_study\fP() is used (except that in a  This is a typical way in which \fBpcre_study\fP() is used (except that in a
1053  real application there should be tests for errors):  real application there should be tests for errors):
# Line 1014  real application there should be tests f Line 1069  real application there should be tests f
1069  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
1070  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
1071  mean that there are any strings of that length that match, but it does  mean that there are any strings of that length that match, but it does
1072  guarantee that no shorter strings match. The value is used by  guarantee that no shorter strings match. The value is used to avoid wasting
1073  \fBpcre_exec()\fP and \fBpcre_dfa_exec()\fP to avoid wasting time by trying to  time by trying to match strings that are shorter than the lower bound. You can
1074  match strings that are shorter than the lower bound. You can find out the value  find out the value in a calling program via the \fBpcre_fullinfo()\fP function.
 in a calling program via the \fBpcre_fullinfo()\fP function.  
1075  .P  .P
1076  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
1077  single fixed starting character. A bitmap of possible starting bytes is  single fixed starting character. A bitmap of possible starting bytes is
1078  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
1079  matching. (In 16-bit mode, the bitmap is used for 16-bit values less than 256.)  matching. (In 16-bit mode, the bitmap is used for 16-bit values less than 256.
1080    In 32-bit mode, the bitmap is used for 32-bit values less than 256.)
1081  .P  .P
1082  These two optimizations apply to both \fBpcre_exec()\fP and  These two optimizations apply to both \fBpcre_exec()\fP and
1083  \fBpcre_dfa_exec()\fP. However, they are not used by \fBpcre_exec()\fP if  \fBpcre_dfa_exec()\fP, and the information is also used by the JIT compiler.
1084  \fBpcre_study()\fP is called with the PCRE_STUDY_JIT_COMPILE option, and  The optimizations can be disabled by setting the PCRE_NO_START_OPTIMIZE option
1085  just-in-time compiling is successful. The optimizations can be disabled by  when calling \fBpcre_exec()\fP or \fBpcre_dfa_exec()\fP, but if this is done,
1086  setting the PCRE_NO_START_OPTIMIZE option when calling \fBpcre_exec()\fP or  JIT execution is also disabled. You might want to do this if your pattern
1087  \fBpcre_dfa_exec()\fP. You might want to do this if your pattern contains  contains callouts or (*MARK) and you want to make use of these facilities in
1088  callouts or (*MARK) (which cannot be handled by the JIT compiler), and you want  cases where matching fails. See the discussion of PCRE_NO_START_OPTIMIZE
 to make use of these facilities in cases where matching fails. See the  
 discussion of PCRE_NO_START_OPTIMIZE  
1089  .\" HTML <a href="#execoptions">  .\" HTML <a href="#execoptions">
1090  .\" </a>  .\" </a>
1091  below.  below.
# Line 1120  the following negative numbers: Line 1173  the following negative numbers:
1173    PCRE_ERROR_NULL           the argument \fIcode\fP was NULL    PCRE_ERROR_NULL           the argument \fIcode\fP was NULL
1174                              the argument \fIwhere\fP was NULL                              the argument \fIwhere\fP was NULL
1175    PCRE_ERROR_BADMAGIC       the "magic number" was not found    PCRE_ERROR_BADMAGIC       the "magic number" was not found
1176    PCRE_ERROR_BADENDIANNESS  the pattern was compiled with different    PCRE_ERROR_BADENDIANNESS  the pattern was compiled with different
1177                              endianness                              endianness
1178    PCRE_ERROR_BADOPTION      the value of \fIwhat\fP was invalid    PCRE_ERROR_BADOPTION      the value of \fIwhat\fP was invalid
1179  .sp  .sp
1180  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
1181  check against passing an arbitrary memory pointer. The endianness error can  check against passing an arbitrary memory pointer. The endianness error can
1182  occur if a compiled pattern is saved and reloaded on a different host. Here is  occur if a compiled pattern is saved and reloaded on a different host. Here is
1183  a typical call of \fBpcre_fullinfo()\fP, to obtain the length of the compiled  a typical call of \fBpcre_fullinfo()\fP, to obtain the length of the compiled
1184  pattern:  pattern:
# Line 1168  where data units are bytes.) The fourth Line 1221  where data units are bytes.) The fourth
1221  variable.  variable.
1222  .P  .P
1223  If there is a fixed first value, for example, the letter "c" from a pattern  If there is a fixed first value, for example, the letter "c" from a pattern
1224  such as (cat|cow|coyote), its value is returned. In the 8-bit library, the  such as (cat|cow|coyote), its value is returned. In the 8-bit library, the
1225  value is always less than 256; in the 16-bit library the value can be up to  value is always less than 256. In the 16-bit library the value can be up to
1226  0xffff.  0xffff. In the 32-bit library the value can be up to 0x10ffff.
1227  .P  .P
1228  If there is no fixed first value, and if either  If there is no fixed first value, and if either
1229  .sp  .sp
# Line 1183  starts with "^", or Line 1236  starts with "^", or
1236  -1 is returned, indicating that the pattern matches only at the start of a  -1 is returned, indicating that the pattern matches only at the start of a
1237  subject string or after any newline within the string. Otherwise -2 is  subject string or after any newline within the string. Otherwise -2 is
1238  returned. For anchored patterns, -2 is returned.  returned. For anchored patterns, -2 is returned.
1239    .P
1240    Since for the 32-bit library using the non-UTF-32 mode, this function is unable
1241    to return the full 32-bit range of the character, this value is deprecated;
1242    instead the PCRE_INFO_FIRSTCHARACTERFLAGS and PCRE_INFO_FIRSTCHARACTER values
1243    should be used.
1244  .sp  .sp
1245    PCRE_INFO_FIRSTTABLE    PCRE_INFO_FIRSTTABLE
1246  .sp  .sp
# Line 1205  Return 1 if the (?J) or (?-J) option set Line 1263  Return 1 if the (?J) or (?-J) option set
1263  .sp  .sp
1264    PCRE_INFO_JIT    PCRE_INFO_JIT
1265  .sp  .sp
1266  Return 1 if the pattern was studied with the PCRE_STUDY_JIT_COMPILE option, and  Return 1 if the pattern was studied with one of the JIT options, and
1267  just-in-time compiling was successful. The fourth argument should point to an  just-in-time compiling was successful. The fourth argument should point to an
1268  \fBint\fP variable. A return value of 0 means that JIT support is not available  \fBint\fP variable. A return value of 0 means that JIT support is not available
1269  in this version of PCRE, or that the pattern was not studied with the  in this version of PCRE, or that the pattern was not studied with a JIT option,
1270  PCRE_STUDY_JIT_COMPILE option, or that the JIT compiler could not handle this  or that the JIT compiler could not handle this particular pattern. See the
 particular pattern. See the  
1271  .\" HREF  .\" HREF
1272  \fBpcrejit\fP  \fBpcrejit\fP
1273  .\"  .\"
# Line 1218  documentation for details of what can an Line 1275  documentation for details of what can an
1275  .sp  .sp
1276    PCRE_INFO_JITSIZE    PCRE_INFO_JITSIZE
1277  .sp  .sp
1278  If the pattern was successfully studied with the PCRE_STUDY_JIT_COMPILE option,  If the pattern was successfully studied with a JIT option, return the size of
1279  return the size of the JIT compiled code, otherwise return zero. The fourth  the JIT compiled code, otherwise return zero. The fourth argument should point
1280  argument should point to a \fBsize_t\fP variable.  to a \fBsize_t\fP variable.
1281  .sp  .sp
1282    PCRE_INFO_LASTLITERAL    PCRE_INFO_LASTLITERAL
1283  .sp  .sp
# Line 1231  value, -1 is returned. For anchored patt Line 1288  value, -1 is returned. For anchored patt
1288  only if it follows something of variable length. For example, for the pattern  only if it follows something of variable length. For example, for the pattern
1289  /^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
1290  is -1.  is -1.
1291    .P
1292    Since for the 32-bit library using the non-UTF-32 mode, this function is unable
1293    to return the full 32-bit range of the character, this value is deprecated;
1294    instead the PCRE_INFO_REQUIREDCHARFLAGS and PCRE_INFO_REQUIREDCHAR values should
1295    be used.
1296    .sp
1297      PCRE_INFO_MAXLOOKBEHIND
1298    .sp
1299    Return the number of characters (NB not bytes) in the longest lookbehind
1300    assertion in the pattern. Note that the simple assertions \eb and \eB require a
1301    one-character lookbehind. This information is useful when doing multi-segment
1302    matching using the partial matching facilities.
1303  .sp  .sp
1304    PCRE_INFO_MINLENGTH    PCRE_INFO_MINLENGTH
1305  .sp  .sp
# Line 1263  length of the longest name. PCRE_INFO_NA Line 1332  length of the longest name. PCRE_INFO_NA
1332  entry of the table. This is a pointer to \fBchar\fP in the 8-bit library, where  entry of the table. This is a pointer to \fBchar\fP in the 8-bit library, where
1333  the first two bytes of each entry are the number of the capturing parenthesis,  the first two bytes of each entry are the number of the capturing parenthesis,
1334  most significant byte first. In the 16-bit library, the pointer points to  most significant byte first. In the 16-bit library, the pointer points to
1335  16-bit data units, the first of which contains the parenthesis number. The rest  16-bit data units, the first of which contains the parenthesis number.
1336    In the 32-bit library, the pointer points to 32-bit data units, the first of
1337    which contains the parenthesis number. The rest
1338  of the entry is the corresponding name, zero terminated.  of the entry is the corresponding name, zero terminated.
1339  .P  .P
1340  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
# Line 1365  is made available via this option so tha Line 1436  is made available via this option so tha
1436  \fBpcreprecompile\fP  \fBpcreprecompile\fP
1437  .\"  .\"
1438  documentation for details).  documentation for details).
1439    .sp
1440      PCRE_INFO_FIRSTCHARACTERFLAGS
1441    .sp
1442    Return information about the first data unit of any matched string, for a
1443    non-anchored pattern. The fourth argument should point to an \fBint\fP
1444    variable.
1445    .P
1446    If there is a fixed first value, for example, the letter "c" from a pattern
1447    such as (cat|cow|coyote), 1 is returned, and the character value can be
1448    retrieved using PCRE_INFO_FIRSTCHARACTER.
1449    .P
1450    If there is no fixed first value, and if either
1451    .sp
1452    (a) the pattern was compiled with the PCRE_MULTILINE option, and every branch
1453    starts with "^", or
1454    .sp
1455    (b) every branch of the pattern starts with ".*" and PCRE_DOTALL is not set
1456    (if it were set, the pattern would be anchored),
1457    .sp
1458    2 is returned, indicating that the pattern matches only at the start of a
1459    subject string or after any newline within the string. Otherwise 0 is
1460    returned. For anchored patterns, 0 is returned.
1461    .sp
1462      PCRE_INFO_FIRSTCHARACTER
1463    .sp
1464    Return the fixed first character value, if PCRE_INFO_FIRSTCHARACTERFLAGS
1465    returned 1; otherwise returns 0. The fourth argument should point to an
1466    \fBuint_t\fP variable.
1467    .P
1468    In the 8-bit library, the value is always less than 256. In the 16-bit library
1469    the value can be up to 0xffff. In the 32-bit library in UTF-32 mode the value
1470    can be up to 0x10ffff, and up to 0xffffffff when not using UTF-32 mode.
1471    .P
1472    If there is no fixed first value, and if either
1473    .sp
1474    (a) the pattern was compiled with the PCRE_MULTILINE option, and every branch
1475    starts with "^", or
1476    .sp
1477    (b) every branch of the pattern starts with ".*" and PCRE_DOTALL is not set
1478    (if it were set, the pattern would be anchored),
1479    .sp
1480    -1 is returned, indicating that the pattern matches only at the start of a
1481    subject string or after any newline within the string. Otherwise -2 is
1482    returned. For anchored patterns, -2 is returned.
1483    .sp
1484      PCRE_INFO_REQUIREDCHARFLAGS
1485    .sp
1486    Returns 1 if there is a rightmost literal data unit that must exist in any
1487    matched string, other than at its start. The fourth argument should  point to
1488    an \fBint\fP variable. If there is no such value, 0 is returned. If returning
1489    1, the character value itself can be retrieved using PCRE_INFO_REQUIREDCHAR.
1490    .P
1491    For anchored patterns, a last literal value is recorded only if it follows
1492    something of variable length. For example, for the pattern /^a\ed+z\ed+/ the
1493    returned value 1 (with "z" returned from PCRE_INFO_REQUIREDCHAR), but for
1494    /^a\edz\ed/ the returned value is 0.
1495    .sp
1496      PCRE_INFO_REQUIREDCHAR
1497    .sp
1498    Return the value of the rightmost literal data unit that must exist in any
1499    matched string, other than at its start, if such a value has been recorded. The
1500    fourth argument should point to an \fBuint32_t\fP variable. If there is no such
1501    value, 0 is returned.
1502  .  .
1503  .  .
1504  .SH "REFERENCE COUNTS"  .SH "REFERENCE COUNTS"
# Line 1459  fields (not necessarily in this order): Line 1593  fields (not necessarily in this order):
1593    const unsigned char *\fItables\fP;    const unsigned char *\fItables\fP;
1594    unsigned char **\fImark\fP;    unsigned char **\fImark\fP;
1595  .sp  .sp
1596  In the 16-bit version of this structure, the \fImark\fP field has type  In the 16-bit version of this structure, the \fImark\fP field has type
1597  "PCRE_UCHAR16 **".  "PCRE_UCHAR16 **".
1598    .sp
1599    In the 32-bit version of this structure, the \fImark\fP field has type
1600    "PCRE_UCHAR32 **".
1601  .P  .P
1602  The \fIflags\fP field is a bitmap that specifies which of the other fields  The \fIflags\fP field is used to specify which of the other fields are set. The
1603  are set. The flag bits are:  flag bits are:
1604  .sp  .sp
1605    PCRE_EXTRA_STUDY_DATA    PCRE_EXTRA_CALLOUT_DATA
1606    PCRE_EXTRA_EXECUTABLE_JIT    PCRE_EXTRA_EXECUTABLE_JIT
1607      PCRE_EXTRA_MARK
1608    PCRE_EXTRA_MATCH_LIMIT    PCRE_EXTRA_MATCH_LIMIT
1609    PCRE_EXTRA_MATCH_LIMIT_RECURSION    PCRE_EXTRA_MATCH_LIMIT_RECURSION
1610    PCRE_EXTRA_CALLOUT_DATA    PCRE_EXTRA_STUDY_DATA
1611    PCRE_EXTRA_TABLES    PCRE_EXTRA_TABLES
   PCRE_EXTRA_MARK  
1612  .sp  .sp
1613  Other flag bits should be set to zero. The \fIstudy_data\fP field and sometimes  Other flag bits should be set to zero. The \fIstudy_data\fP field and sometimes
1614  the \fIexecutable_jit\fP field are set in the \fBpcre_extra\fP block that is  the \fIexecutable_jit\fP field are set in the \fBpcre_extra\fP block that is
1615  returned by \fBpcre_study()\fP, together with the appropriate flag bits. You  returned by \fBpcre_study()\fP, together with the appropriate flag bits. You
1616  should not set these yourself, but you may add to the block by setting the  should not set these yourself, but you may add to the block by setting other
1617  other fields and their corresponding flag bits.  fields and their corresponding flag bits.
1618  .P  .P
1619  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
1620  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,
# Line 1492  patterns that are not anchored, the coun Line 1629  patterns that are not anchored, the coun
1629  in the subject string.  in the subject string.
1630  .P  .P
1631  When \fBpcre_exec()\fP is called with a pattern that was successfully studied  When \fBpcre_exec()\fP is called with a pattern that was successfully studied
1632  with the PCRE_STUDY_JIT_COMPILE option, the way that the matching is executed  with a JIT option, the way that the matching is executed is entirely different.
1633  is entirely different. However, there is still the possibility of runaway  However, there is still the possibility of runaway matching that goes on for a
1634  matching that goes on for a very long time, and so the \fImatch_limit\fP value  very long time, and so the \fImatch_limit\fP value is also used in this case
1635  is also used in this case (but in a different way) to limit how long the  (but in a different way) to limit how long the matching can continue.
 matching can continue.  
1636  .P  .P
1637  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
1638  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 1514  This limit is of use only if it is set s Line 1650  This limit is of use only if it is set s
1650  Limiting the recursion depth limits the amount of machine stack that can be  Limiting the recursion depth limits the amount of machine stack that can be
1651  used, or, when PCRE has been compiled to use memory on the heap instead of the  used, or, when PCRE has been compiled to use memory on the heap instead of the
1652  stack, the amount of heap memory that can be used. This limit is not relevant,  stack, the amount of heap memory that can be used. This limit is not relevant,
1653  and is ignored, if the pattern was successfully studied with  and is ignored, when matching is done using JIT compiled code.
 PCRE_STUDY_JIT_COMPILE.  
1654  .P  .P
1655  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
1656  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 1572  documentation. Line 1707  documentation.
1707  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
1708  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,
1709  PCRE_NOTBOL, PCRE_NOTEOL, PCRE_NOTEMPTY, PCRE_NOTEMPTY_ATSTART,  PCRE_NOTBOL, PCRE_NOTEOL, PCRE_NOTEMPTY, PCRE_NOTEMPTY_ATSTART,
1710  PCRE_NO_START_OPTIMIZE, PCRE_NO_UTF8_CHECK, PCRE_PARTIAL_SOFT, and  PCRE_NO_START_OPTIMIZE, PCRE_NO_UTF8_CHECK, PCRE_PARTIAL_HARD, and
1711  PCRE_PARTIAL_HARD.  PCRE_PARTIAL_SOFT.
1712  .P  .P
1713  If the pattern was successfully studied with the PCRE_STUDY_JIT_COMPILE option,  If the pattern was successfully studied with one of the just-in-time (JIT)
1714  the only supported options for JIT execution are PCRE_NO_UTF8_CHECK,  compile options, the only supported options for JIT execution are
1715  PCRE_NOTBOL, PCRE_NOTEOL, PCRE_NOTEMPTY, and PCRE_NOTEMPTY_ATSTART. Note in  PCRE_NO_UTF8_CHECK, PCRE_NOTBOL, PCRE_NOTEOL, PCRE_NOTEMPTY,
1716  particular that partial matching is not supported. If an unsupported option is  PCRE_NOTEMPTY_ATSTART, PCRE_PARTIAL_HARD, and PCRE_PARTIAL_SOFT. If an
1717  used, JIT execution is disabled and the normal interpretive code in  unsupported option is used, JIT execution is disabled and the normal
1718  \fBpcre_exec()\fP is run.  interpretive code in \fBpcre_exec()\fP is run.
1719  .sp  .sp
1720    PCRE_ANCHORED    PCRE_ANCHORED
1721  .sp  .sp
# Line 1699  causing performance to suffer, but ensur Line 1834  causing performance to suffer, but ensur
1834  "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)
1835  are considered at every possible starting position in the subject string. If  are considered at every possible starting position in the subject string. If
1836  PCRE_NO_START_OPTIMIZE is set at compile time, it cannot be unset at matching  PCRE_NO_START_OPTIMIZE is set at compile time, it cannot be unset at matching
1837  time.  time. The use of PCRE_NO_START_OPTIMIZE disables JIT execution; when it is set,
1838    matching is always done using interpretively.
1839  .P  .P
1840  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.
1841  Consider the pattern  Consider the pattern
# Line 1732  returned. Line 1868  returned.
1868  .sp  .sp
1869  When PCRE_UTF8 is set at compile time, the validity of the subject as a UTF-8  When PCRE_UTF8 is set at compile time, the validity of the subject as a UTF-8
1870  string is automatically checked when \fBpcre_exec()\fP is subsequently called.  string is automatically checked when \fBpcre_exec()\fP is subsequently called.
1871  The value of \fIstartoffset\fP is also checked to ensure that it points to the  The entire string is checked before any other processing takes place. The value
1872  start of a UTF-8 character. There is a discussion about the validity of UTF-8  of \fIstartoffset\fP is also checked to ensure that it points to the start of a
1873  strings in the  UTF-8 character. There is a discussion about the
1874    .\" HTML <a href="pcreunicode.html#utf8strings">
1875    .\" </a>
1876    validity of UTF-8 strings
1877    .\"
1878    in the
1879  .\" HREF  .\" HREF
1880  \fBpcreunicode\fP  \fBpcreunicode\fP
1881  .\"  .\"
# Line 1882  string that it matched that is returned. Line 2023  string that it matched that is returned.
2023  .P  .P
2024  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
2025  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
2026  returns a value of zero. If neither the actual string matched not any captured  returns a value of zero. If neither the actual string matched nor any captured
2027  substrings are of interest, \fBpcre_exec()\fP may be called with \fIovector\fP  substrings are of interest, \fBpcre_exec()\fP may be called with \fIovector\fP
2028  passed as NULL and \fIovecsize\fP as zero. However, if the pattern contains  passed as NULL and \fIovecsize\fP as zero. However, if the pattern contains
2029  back references and the \fIovector\fP is not big enough to remember the related  back references and the \fIovector\fP is not big enough to remember the related
# Line 2082  time. Line 2223  time.
2223  .sp  .sp
2224    PCRE_ERROR_JIT_STACKLIMIT (-27)    PCRE_ERROR_JIT_STACKLIMIT (-27)
2225  .sp  .sp
2226  This error is returned when a pattern that was successfully studied using the  This error is returned when a pattern that was successfully studied using a
2227  PCRE_STUDY_JIT_COMPILE option is being matched, but the memory available for  JIT compile option is being matched, but the memory available for the
2228  the just-in-time processing stack is not large enough. See the  just-in-time processing stack is not large enough. See the
2229  .\" HREF  .\" HREF
2230  \fBpcrejit\fP  \fBpcrejit\fP
2231  .\"  .\"
2232  documentation for more details.  documentation for more details.
2233  .sp  .sp
2234    PCRE_ERROR_BADMODE (-28)    PCRE_ERROR_BADMODE        (-28)
2235    .sp
2236    This error is given if a pattern that was compiled by the 8-bit library is
2237    passed to a 16-bit or 32-bit library function, or vice versa.
2238  .sp  .sp
2239  This error is given if a pattern that was compiled by the 8-bit library is    PCRE_ERROR_BADENDIANNESS  (-29)
 passed to a 16-bit library function, or vice versa.  
2240  .sp  .sp
2241    PCRE_ERROR_BADENDIANNESS (-29)  This error is given if a pattern that was compiled and saved is reloaded on a
2242  .sp  host with different endianness. The utility function
2243  This error is given if a pattern that was compiled and saved is reloaded on a  \fBpcre_pattern_to_host_byte_order()\fP can be used to convert such a pattern
 host with different endianness. The utility function  
 \fBpcre_pattern_to_host_byte_order()\fP can be used to convert such a pattern  
2244  so that it runs on the new host.  so that it runs on the new host.
2245    .sp
2246      PCRE_ERROR_JIT_BADOPTION
2247    .sp
2248    This error is returned when a pattern that was successfully studied using a JIT
2249    compile option is being matched, but the matching mode (partial or complete
2250    match) does not correspond to any JIT compilation mode. When the JIT fast path
2251    function is used, this error may be also given for invalid options. See the
2252    .\" HREF
2253    \fBpcrejit\fP
2254    .\"
2255    documentation for more details.
2256    .sp
2257      PCRE_ERROR_BADLENGTH      (-32)
2258    .sp
2259    This error is given if \fBpcre_exec()\fP is called with a negative value for
2260    the \fIlength\fP argument.
2261  .P  .P
2262  Error numbers -16 to -20 and -22 are not used by \fBpcre_exec()\fP.  Error numbers -16 to -20, -22, and 30 are not used by \fBpcre_exec()\fP.
2263  .  .
2264  .  .
2265  .\" HTML <a name="badutf8reasons"></a>  .\" HTML <a name="badutf8reasons"></a>
2266  .SS "Reason codes for invalid UTF-8 strings"  .SS "Reason codes for invalid UTF-8 strings"
2267  .rs  .rs
2268  .sp  .sp
2269  This section applies only to the 8-bit library. The corresponding information  This section applies only to the 8-bit library. The corresponding information
2270  for the 16-bit library is given in the  for the 16-bit library is given in the
2271  .\" HREF  .\" HREF
2272  \fBpcre16\fP  \fBpcre16\fP
2273  .\"  .\"
2274    page. The corresponding information for the 32-bit library is given in the
2275    .\" HREF
2276    \fBpcre32\fP
2277    .\"
2278  page.  page.
2279  .P  .P
2280  When \fBpcre_exec()\fP returns either PCRE_ERROR_BADUTF8 or  When \fBpcre_exec()\fP returns either PCRE_ERROR_BADUTF8 or
# Line 2184  character. Line 2345  character.
2345  .sp  .sp
2346  The first byte of a character has the value 0xfe or 0xff. These values can  The first byte of a character has the value 0xfe or 0xff. These values can
2347  never occur in a valid UTF-8 string.  never occur in a valid UTF-8 string.
2348    .sp
2349      PCRE_UTF8_ERR2
2350    .sp
2351    Non-character. These are the last two characters in each plane (0xfffe, 0xffff,
2352    0x1fffe, 0x1ffff .. 0x10fffe, 0x10ffff), and the characters 0xfdd0..0xfdef.
2353  .  .
2354  .  .
2355  .SH "EXTRACTING CAPTURED SUBSTRINGS BY NUMBER"  .SH "EXTRACTING CAPTURED SUBSTRINGS BY NUMBER"
# Line 2413  other alternatives. Ultimately, when it Line 2579  other alternatives. Ultimately, when it
2579  will yield PCRE_ERROR_NOMATCH.  will yield PCRE_ERROR_NOMATCH.
2580  .  .
2581  .  .
2582    .SH "OBTAINING AN ESTIMATE OF STACK USAGE"
2583    .rs
2584    .sp
2585    Matching certain patterns using \fBpcre_exec()\fP can use a lot of process
2586    stack, which in certain environments can be rather limited in size. Some users
2587    find it helpful to have an estimate of the amount of stack that is used by
2588    \fBpcre_exec()\fP, to help them set recursion limits, as described in the
2589    .\" HREF
2590    \fBpcrestack\fP
2591    .\"
2592    documentation. The estimate that is output by \fBpcretest\fP when called with
2593    the \fB-m\fP and \fB-C\fP options is obtained by calling \fBpcre_exec\fP with
2594    the values NULL, NULL, NULL, -999, and -999 for its first five arguments.
2595    .P
2596    Normally, if its first argument is NULL, \fBpcre_exec()\fP immediately returns
2597    the negative error code PCRE_ERROR_NULL, but with this special combination of
2598    arguments, it returns instead a negative number whose absolute value is the
2599    approximate stack frame size in bytes. (A negative number is used so that it is
2600    clear that no match has happened.) The value is approximate because in some
2601    cases, recursive calls to \fBpcre_exec()\fP occur when there are one or two
2602    additional variables on the stack.
2603    .P
2604    If PCRE has been compiled to use the heap instead of the stack for recursion,
2605    the value returned is the size of each block that is obtained from the heap.
2606    .
2607    .
2608  .\" HTML <a name="dfamatch"></a>  .\" HTML <a name="dfamatch"></a>
2609  .SH "MATCHING A PATTERN: THE ALTERNATIVE FUNCTION"  .SH "MATCHING A PATTERN: THE ALTERNATIVE FUNCTION"
2610  .rs  .rs
# Line 2594  When a recursive subpattern is processed Line 2786  When a recursive subpattern is processed
2786  recursively, using private vectors for \fIovector\fP and \fIworkspace\fP. This  recursively, using private vectors for \fIovector\fP and \fIworkspace\fP. This
2787  error is given if the output vector is not large enough. This should be  error is given if the output vector is not large enough. This should be
2788  extremely rare, as a vector of size 1000 is used.  extremely rare, as a vector of size 1000 is used.
2789    .sp
2790      PCRE_ERROR_DFA_BADRESTART (-30)
2791    .sp
2792    When \fBpcre_dfa_exec()\fP is called with the \fBPCRE_DFA_RESTART\fP option,
2793    some plausibility checks are made on the contents of the workspace, which
2794    should contain data about the previous partial match. If any of these checks
2795    fail, this error is given.
2796  .  .
2797  .  .
2798  .SH "SEE ALSO"  .SH "SEE ALSO"
2799  .rs  .rs
2800  .sp  .sp
2801  \fBpcre16\fP(3), \fBpcrebuild\fP(3), \fBpcrecallout\fP(3), \fBpcrecpp(3)\fP(3),  \fBpcre16\fP(3), \fBpcre32\fP(3), \fBpcrebuild\fP(3), \fBpcrecallout\fP(3),
2802  \fBpcrematching\fP(3), \fBpcrepartial\fP(3), \fBpcreposix\fP(3),  \fBpcrecpp(3)\fP(3), \fBpcrematching\fP(3), \fBpcrepartial\fP(3),
2803  \fBpcreprecompile\fP(3), \fBpcresample\fP(3), \fBpcrestack\fP(3).  \fBpcreposix\fP(3), \fBpcreprecompile\fP(3), \fBpcresample\fP(3),
2804    \fBpcrestack\fP(3).
2805  .  .
2806  .  .
2807  .SH AUTHOR  .SH AUTHOR
# Line 2618  Cambridge CB2 3QH, England. Line 2818  Cambridge CB2 3QH, England.
2818  .rs  .rs
2819  .sp  .sp
2820  .nf  .nf
2821  Last updated: 17 January 2012  Last updated: 31 October 2012
2822  Copyright (c) 1997-2012 University of Cambridge.  Copyright (c) 1997-2012 University of Cambridge.
2823  .fi  .fi

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