/[pcre]/code/trunk/doc/pcreapi.3
ViewVC logotype

Diff of /code/trunk/doc/pcreapi.3

Parent Directory Parent Directory | Revision Log Revision Log | View Patch Patch

revision 926 by ph10, Wed Feb 22 15:01:32 2012 UTC revision 1113 by chpe, Tue Oct 16 15:57:12 2012 UTC
# Line 1  Line 1 
1  .TH PCREAPI 3  .TH PCREAPI 3 "07 September 2012" "PCRE 8.32"
2  .SH NAME  .SH NAME
3  PCRE - Perl-compatible regular expressions  PCRE - Perl-compatible regular expressions
4  .sp  .sp
# Line 134  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"  .SH "PCRE 8-BIT, 16-BIT AND 32-BIT LIBRARIES"
138  .rs  .rs
139  .sp  .sp
140  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
141  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
142  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
143  describes the 8-bit versions of the functions, with only occasional references  library for handling 32-bit character strings. To avoid too much complication,
144  to the 16-bit library.  this document describes the 8-bit versions of the functions, with only
145    occasional references to the 16-bit and 32-bit libraries.
146  .P  .P
147  The 16-bit functions operate in the same way as their 8-bit counterparts; they  The 16-bit functions operate in the same way as their 8-bit counterparts; they
148  just use different data types for their arguments and results, and their names  just use different data types for their arguments and results, and their names
# Line 150  in its name (for example, PCRE_UTF8), th Line 151  in its name (for example, PCRE_UTF8), th
151  UTF8 replaced by UTF16. This facility is in fact just cosmetic; the 16-bit  UTF8 replaced by UTF16. This facility is in fact just cosmetic; the 16-bit
152  option names define the same bit values.  option names define the same bit values.
153  .P  .P
154    The 32-bit functions operate in the same way as their 8-bit counterparts; they
155    just use different data types for their arguments and results, and their names
156    start with \fBpcre32_\fP instead of \fBpcre_\fP. For every option that has UTF8
157    in its name (for example, PCRE_UTF8), there is a corresponding 32-bit name with
158    UTF8 replaced by UTF32. This facility is in fact just cosmetic; the 32-bit
159    option names define the same bit values.
160    .P
161  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
162  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, unless
163  specified otherwise. More details of the specific differences for the 16-bit  specified otherwise. More details of the specific differences for the 16-bit
# Line 159  library are given in the Line 167  library are given in the
167  .\"  .\"
168  page.  page.
169  .  .
170    .P
171    References to bytes and UTF-8 in this document should be read as references to
172    32-bit data quantities and UTF-32 when using the 32-bit library, unless
173    specified otherwise. More details of the specific differences for the 32-bit
174    library are given in the
175    .\" HREF
176    \fBpcre32\fP
177    .\"
178    page.
179    .
180  .  .
181  .SH "PCRE API OVERVIEW"  .SH "PCRE API OVERVIEW"
182  .rs  .rs
# Line 302  PCRE supports five different conventions Line 320  PCRE supports five different conventions
320  strings: a single CR (carriage return) character, a single LF (linefeed)  strings: a single CR (carriage return) character, a single LF (linefeed)
321  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
322  Unicode newline sequence. The Unicode newline sequences are the three just  Unicode newline sequence. The Unicode newline sequences are the three just
323  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,
324  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
325  (paragraph separator, U+2029).  (paragraph separator, U+2029).
326  .P  .P
# Line 392  not recognized. The following informatio Line 410  not recognized. The following informatio
410    PCRE_CONFIG_UTF8    PCRE_CONFIG_UTF8
411  .sp  .sp
412  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;
413  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
414  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
415    or 32-bit version of this function, the result is PCRE_ERROR_BADOPTION.
416  .sp  .sp
417    PCRE_CONFIG_UTF16    PCRE_CONFIG_UTF16
418  .sp  .sp
419  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;
420  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
421  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
422  version of this function, the result is PCRE_ERROR_BADOPTION.  or 32-bit version of this function, the result is PCRE_ERROR_BADOPTION.
423    .sp
424      PCRE_CONFIG_UTF32
425    .sp
426    The output is an integer that is set to one if UTF-32 support is available;
427    otherwise it is set to zero. This value should normally be given to the 32-bit
428    version of this function, \fBpcre32_config()\fP. If it is given to the 8-bit
429    or 16-bit version of this function, the result is PCRE_ERROR_BADOPTION.
430  .sp  .sp
431    PCRE_CONFIG_UNICODE_PROPERTIES    PCRE_CONFIG_UNICODE_PROPERTIES
432  .sp  .sp
# Line 422  unaligned)". If JIT support is not avail Line 448  unaligned)". If JIT support is not avail
448    PCRE_CONFIG_NEWLINE    PCRE_CONFIG_NEWLINE
449  .sp  .sp
450  The output is an integer whose value specifies the default character sequence  The output is an integer whose value specifies the default character sequence
451  that is recognized as meaning "newline". The four values that are supported  that is recognized as meaning "newline". The values that are supported in
452  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
453  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
454  environments. The default should normally correspond to the standard sequence  same values. However, the value for LF is normally 21, though some EBCDIC
455  for your operating system.  environments use 37. The corresponding values for CRLF are 3349 and 3365. The
456    default should normally correspond to the standard sequence for your operating
457    system.
458  .sp  .sp
459    PCRE_CONFIG_BSR    PCRE_CONFIG_BSR
460  .sp  .sp
# Line 440  or CRLF. The default can be overridden w Line 468  or CRLF. The default can be overridden w
468  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
469  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
470  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
471  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
472  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
473  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
474  of slower matching.  size. Larger values allow larger regular expressions to be compiled, at the
475    expense of slower matching.
476  .sp  .sp
477    PCRE_CONFIG_POSIX_MALLOC_THRESHOLD    PCRE_CONFIG_POSIX_MALLOC_THRESHOLD
478  .sp  .sp
# Line 526  documentation). For those options that c Line 555  documentation). For those options that c
555  the pattern, the contents of the \fIoptions\fP argument specifies their  the pattern, the contents of the \fIoptions\fP argument specifies their
556  settings at the start of compilation and execution. The PCRE_ANCHORED,  settings at the start of compilation and execution. The PCRE_ANCHORED,
557  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
558  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
559  compile time.  compile time.
560  .P  .P
561  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 671  documentation.
671  .sp  .sp
672    PCRE_EXTENDED    PCRE_EXTENDED
673  .sp  .sp
674  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
675  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
676  include the VT character (code 11). In addition, characters between an  include the VT character (code 11). In addition, characters between an
677  unescaped # outside a character class and the next newline, inclusive, are also  unescaped # outside a character class and the next newline, inclusive, are also
678  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 690  comment is a literal newline sequence in
690  happen to represent a newline do not count.  happen to represent a newline do not count.
691  .P  .P
692  This option makes it possible to include comments inside complicated patterns.  This option makes it possible to include comments inside complicated patterns.
693  Note, however, that this applies only to data characters. Whitespace characters  Note, however, that this applies only to data characters. White space characters
694  may never appear within special character sequences in a pattern, for example  may never appear within special character sequences in a pattern, for example
695  within the sequence (?( that introduces a conditional subpattern.  within the sequence (?( that introduces a conditional subpattern.
696  .sp  .sp
# Line 739  indicated by a single character (CR or L Line 768  indicated by a single character (CR or L
768  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
769  CRLF sequence. Setting PCRE_NEWLINE_ANYCRLF specifies that any of the three  CRLF sequence. Setting PCRE_NEWLINE_ANYCRLF specifies that any of the three
770  preceding sequences should be recognized. Setting PCRE_NEWLINE_ANY specifies  preceding sequences should be recognized. Setting PCRE_NEWLINE_ANY specifies
771  that any Unicode newline sequence should be recognized. The Unicode newline  that any Unicode newline sequence should be recognized.
772  sequences are the three just mentioned, plus the single characters VT (vertical  .P
773  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
774  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
775  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
776    (paragraph separator, U+2029). For the 8-bit library, the last two are
777    recognized only in UTF-8 mode.
778    .P
779    When PCRE is compiled to run in an EBCDIC (mainframe) environment, the code for
780    CR is 0x0d, the same as ASCII. However, the character code for LF is normally
781    0x15, though in some EBCDIC environments 0x25 is used. Whichever of these is
782    not LF is made to correspond to Unicode's NEL character. EBCDIC codes are all
783    less than 256. For more details, see the
784    .\" HREF
785    \fBpcrebuild\fP
786    .\"
787    documentation.
788  .P  .P
789  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
790  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 794  PCRE_NEWLINE_CR with PCRE_NEWLINE_LF is
794  other combinations may yield unused numbers and cause an error.  other combinations may yield unused numbers and cause an error.
795  .P  .P
796  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
797  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,
798  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
799  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
800  other circumstances, line break sequences in patterns are treated as literal  other circumstances, line break sequences in patterns are treated as literal
# Line 844  validity checking of subject strings. Line 885  validity checking of subject strings.
885  The following table lists the error codes than may be returned by  The following table lists the error codes than may be returned by
886  \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
887  both compiling functions. Note that error messages are always 8-bit ASCII  both compiling functions. Note that error messages are always 8-bit ASCII
888  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
889  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.
890  .sp  .sp
891     0  no error     0  no error
892     1  \e at end of pattern     1  \e at end of pattern
# Line 926  fallen out of use. To avoid confusion, t Line 967  fallen out of use. To avoid confusion, t
967    72  too many forward references    72  too many forward references
968    73  disallowed Unicode code point (>= 0xd800 && <= 0xdfff)    73  disallowed Unicode code point (>= 0xd800 && <= 0xdfff)
969    74  invalid UTF-16 string (specifically UTF-16)    74  invalid UTF-16 string (specifically UTF-16)
970      75  name is too long in (*MARK), (*PRUNE), (*SKIP), or (*THEN)
971      76  character value in \eu.... sequence is too large
972      77  invalid UTF-32 string (specifically UTF-32)
973  .sp  .sp
974  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
975  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 1002  below
1002  in the section on matching a pattern.  in the section on matching a pattern.
1003  .P  .P
1004  If studying the pattern does not produce any useful information,  If studying the pattern does not produce any useful information,
1005  \fBpcre_study()\fP returns NULL. In that circumstance, if the calling program  \fBpcre_study()\fP returns NULL by default. In that circumstance, if the
1006  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
1007  \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,
1008    if \fBpcre_study()\fP is called with the PCRE_STUDY_EXTRA_NEEDED option, it
1009    returns a \fBpcre_extra\fP block even if studying did not find any additional
1010    information. It may still return NULL, however, if an error occurs in
1011    \fBpcre_study()\fP.
1012  .P  .P
1013  The second argument of \fBpcre_study()\fP contains option bits. There are three  The second argument of \fBpcre_study()\fP contains option bits. There are three
1014  options:  further options in addition to PCRE_STUDY_EXTRA_NEEDED:
1015  .sp  .sp
1016    PCRE_STUDY_JIT_COMPILE    PCRE_STUDY_JIT_COMPILE
1017    PCRE_STUDY_JIT_PARTIAL_HARD_COMPILE    PCRE_STUDY_JIT_PARTIAL_HARD_COMPILE
1018    PCRE_STUDY_JIT_PARTIAL_SOFT_COMPILE    PCRE_STUDY_JIT_PARTIAL_SOFT_COMPILE
1019  .sp  .sp
1020  If any of these are set, and the just-in-time compiler is available, the  If any of these are set, and the just-in-time compiler is available, the
1021  pattern is further compiled into machine code that executes much faster than  pattern is further compiled into machine code that executes much faster than
1022  the \fBpcre_exec()\fP interpretive matching function. If the just-in-time  the \fBpcre_exec()\fP interpretive matching function. If the just-in-time
1023  compiler is not available, these options are ignored. All other bits in the  compiler is not available, these options are ignored. All undefined bits in the
1024  \fIoptions\fP argument must be zero.  \fIoptions\fP argument must be zero.
1025  .P  .P
1026  JIT compilation is a heavyweight optimization. It can take some time for  JIT compilation is a heavyweight optimization. It can take some time for
# Line 1020  real application there should be tests f Line 1068  real application there should be tests f
1068  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
1069  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
1070  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
1071  guarantee that no shorter strings match. The value is used by  guarantee that no shorter strings match. The value is used to avoid wasting
1072  \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
1073  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.  
1074  .P  .P
1075  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
1076  single fixed starting character. A bitmap of possible starting bytes is  single fixed starting character. A bitmap of possible starting bytes is
1077  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
1078  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.
1079    In 32-bit mode, the bitmap is used for 32-bit values less than 256.)
1080  .P  .P
1081  These two optimizations apply to both \fBpcre_exec()\fP and  These two optimizations apply to both \fBpcre_exec()\fP and
1082  \fBpcre_dfa_exec()\fP, and the information is also used by the JIT compiler.  \fBpcre_dfa_exec()\fP, and the information is also used by the JIT compiler.
# Line 1173  variable. Line 1221  variable.
1221  .P  .P
1222  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
1223  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
1224  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
1225  0xffff.  0xffff. In the 32-bit library the value can be up to 0x10ffff.
1226  .P  .P
1227  If there is no fixed first value, and if either  If there is no fixed first value, and if either
1228  .sp  .sp
# Line 1187  starts with "^", or Line 1235  starts with "^", or
1235  -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
1236  subject string or after any newline within the string. Otherwise -2 is  subject string or after any newline within the string. Otherwise -2 is
1237  returned. For anchored patterns, -2 is returned.  returned. For anchored patterns, -2 is returned.
1238    .P
1239    Since for the 32-bit library using the non-UTF-32 mode, this function is unable
1240    to return the full 32-bit range of the character, this value is deprecated;
1241    instead the PCRE_INFO_FIRSTCHARACTERFLAGS and PCRE_INFO_FIRSTCHARACTER values should
1242    be used.
1243  .sp  .sp
1244    PCRE_INFO_FIRSTTABLE    PCRE_INFO_FIRSTTABLE
1245  .sp  .sp
# Line 1234  value, -1 is returned. For anchored patt Line 1287  value, -1 is returned. For anchored patt
1287  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
1288  /^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
1289  is -1.  is -1.
1290    .P
1291    Since for the 32-bit library using the non-UTF-32 mode, this function is unable
1292    to return the full 32-bit range of the character, this value is deprecated;
1293    instead the PCRE_INFO_REQUIREDCHARFLAGS and PCRE_INFO_REQUIREDCHAR values should
1294    be used.
1295    .sp
1296      PCRE_INFO_MAXLOOKBEHIND
1297    .sp
1298    Return the number of characters (NB not bytes) in the longest lookbehind
1299    assertion in the pattern. Note that the simple assertions \eb and \eB require a
1300    one-character lookbehind. This information is useful when doing multi-segment
1301    matching using the partial matching facilities.
1302  .sp  .sp
1303    PCRE_INFO_MINLENGTH    PCRE_INFO_MINLENGTH
1304  .sp  .sp
# Line 1266  length of the longest name. PCRE_INFO_NA Line 1331  length of the longest name. PCRE_INFO_NA
1331  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
1332  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,
1333  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
1334  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.
1335    In the 32-bit library, the pointer points to 32-bit data units, the first of
1336    which contains the parenthesis number. The rest
1337  of the entry is the corresponding name, zero terminated.  of the entry is the corresponding name, zero terminated.
1338  .P  .P
1339  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 1368  is made available via this option so tha Line 1435  is made available via this option so tha
1435  \fBpcreprecompile\fP  \fBpcreprecompile\fP
1436  .\"  .\"
1437  documentation for details).  documentation for details).
1438    .sp
1439      PCRE_INFO_FIRSTCHARACTERFLAGS
1440    .sp
1441    Return information about the first data unit of any matched string, for a
1442    non-anchored pattern. The fourth argument should point to an \fBint\fP
1443    variable.
1444    .P
1445    If there is a fixed first value, for example, the letter "c" from a pattern
1446    such as (cat|cow|coyote), 1 is returned, and the character value can be
1447    retrieved using PCRE_INFO_FIRSTCHARACTER.
1448    .P
1449    If there is no fixed first value, and if either
1450    .sp
1451    (a) the pattern was compiled with the PCRE_MULTILINE option, and every branch
1452    starts with "^", or
1453    .sp
1454    (b) every branch of the pattern starts with ".*" and PCRE_DOTALL is not set
1455    (if it were set, the pattern would be anchored),
1456    .sp
1457    2 is returned, indicating that the pattern matches only at the start of a
1458    subject string or after any newline within the string. Otherwise 0 is
1459    returned. For anchored patterns, 0 is returned.
1460    .sp
1461      PCRE_INFO_FIRSTCHARACTER
1462    .sp
1463    Return the fixed first character value, if PCRE_INFO_FIRSTCHARACTERFLAGS returned 1;
1464    otherwise returns 0. The fourth argument should point to an \fBuint_t\fP
1465    variable.
1466    .P
1467    In the 8-bit library, the value is always less than 256. In the 16-bit library
1468    the value can be up to 0xffff. In the 32-bit library in UTF-32 mode the value
1469    can be up to 0x10ffff, and up to 0xffffffff when not using UTF-32 mode.
1470    .P
1471    If there is no fixed first value, and if either
1472    .sp
1473    (a) the pattern was compiled with the PCRE_MULTILINE option, and every branch
1474    starts with "^", or
1475    .sp
1476    (b) every branch of the pattern starts with ".*" and PCRE_DOTALL is not set
1477    (if it were set, the pattern would be anchored),
1478    .sp
1479    -1 is returned, indicating that the pattern matches only at the start of a
1480    subject string or after any newline within the string. Otherwise -2 is
1481    returned. For anchored patterns, -2 is returned.
1482    .sp
1483      PCRE_INFO_REQUIREDCHARFLAGS
1484    .sp
1485    Returns 1 if there is a rightmost literal data unit that must exist in any matched
1486    string, other than at its start. The fourth argument should  point to an \fBint\fP
1487    variable. If there is no such value, 0 is returned. If returning 1, the character
1488    value itself can be retrieved using PCRE_INFO_REQUIREDCHAR.
1489    .P
1490    For anchored patterns, a last literal value is recorded only if it follows something
1491    of variable length. For example, for the pattern /^a\ed+z\ed+/ the returned value
1492    1 (with "z" returned from PCRE_INFO_REQUIREDCHAR), but for /^a\edz\ed/ the returned
1493    value is 0.
1494    .sp
1495      PCRE_INFO_REQUIREDCHAR
1496    .sp
1497    Return the value of the rightmost literal data unit that must exist in any
1498    matched string, other than at its start, if such a value has been recorded. The
1499    fourth argument should point to an \fBuint32_t\fP variable. If there is no such
1500    value, 0 is returned.
1501  .  .
1502  .  .
1503  .SH "REFERENCE COUNTS"  .SH "REFERENCE COUNTS"
# Line 1464  fields (not necessarily in this order): Line 1594  fields (not necessarily in this order):
1594  .sp  .sp
1595  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
1596  "PCRE_UCHAR16 **".  "PCRE_UCHAR16 **".
1597    .sp
1598    In the 32-bit version of this structure, the \fImark\fP field has type
1599    "PCRE_UCHAR32 **".
1600  .P  .P
1601  The \fIflags\fP field is used to specify which of the other fields are set. The  The \fIflags\fP field is used to specify which of the other fields are set. The
1602  flag bits are:  flag bits are:
# Line 1516  This limit is of use only if it is set s Line 1649  This limit is of use only if it is set s
1649  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
1650  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
1651  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,
1652  and is ignored, when matching is done using JIT compiled code.  and is ignored, when matching is done using JIT compiled code.
1653  .P  .P
1654  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
1655  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 1700  causing performance to suffer, but ensur Line 1833  causing performance to suffer, but ensur
1833  "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)
1834  are considered at every possible starting position in the subject string. If  are considered at every possible starting position in the subject string. If
1835  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
1836  time. The use of PCRE_NO_START_OPTIMIZE disables JIT execution; when it is set,  time. The use of PCRE_NO_START_OPTIMIZE disables JIT execution; when it is set,
1837  matching is always done using interpretively.  matching is always done using interpretively.
1838  .P  .P
1839  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.
# Line 1734  returned. Line 1867  returned.
1867  .sp  .sp
1868  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
1869  string is automatically checked when \fBpcre_exec()\fP is subsequently called.  string is automatically checked when \fBpcre_exec()\fP is subsequently called.
1870  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
1871  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
1872  strings in the  UTF-8 character. There is a discussion about the
1873    .\" HTML <a href="pcreunicode.html#utf8strings">
1874    .\" </a>
1875    validity of UTF-8 strings
1876    .\"
1877    in the
1878  .\" HREF  .\" HREF
1879  \fBpcreunicode\fP  \fBpcreunicode\fP
1880  .\"  .\"
# Line 1884  string that it matched that is returned. Line 2022  string that it matched that is returned.
2022  .P  .P
2023  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
2024  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
2025  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
2026  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
2027  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
2028  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 2092  just-in-time processing stack is not lar Line 2230  just-in-time processing stack is not lar
2230  .\"  .\"
2231  documentation for more details.  documentation for more details.
2232  .sp  .sp
2233    PCRE_ERROR_BADMODE (-28)    PCRE_ERROR_BADMODE        (-28)
2234  .sp  .sp
2235  This error is given if a pattern that was compiled by the 8-bit library is  This error is given if a pattern that was compiled by the 8-bit library is
2236  passed to a 16-bit library function, or vice versa.  passed to a 16-bit or 32-bit library function, or vice versa.
2237  .sp  .sp
2238    PCRE_ERROR_BADENDIANNESS (-29)    PCRE_ERROR_BADENDIANNESS  (-29)
2239  .sp  .sp
2240  This error is given if a pattern that was compiled and saved is reloaded on a  This error is given if a pattern that was compiled and saved is reloaded on a
2241  host with different endianness. The utility function  host with different endianness. The utility function
2242  \fBpcre_pattern_to_host_byte_order()\fP can be used to convert such a pattern  \fBpcre_pattern_to_host_byte_order()\fP can be used to convert such a pattern
2243  so that it runs on the new host.  so that it runs on the new host.
2244  .P  .P
2245  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.
2246  .  .
2247  .  .
2248  .\" HTML <a name="badutf8reasons"></a>  .\" HTML <a name="badutf8reasons"></a>
# Line 2116  for the 16-bit library is given in the Line 2254  for the 16-bit library is given in the
2254  .\" HREF  .\" HREF
2255  \fBpcre16\fP  \fBpcre16\fP
2256  .\"  .\"
2257    page. The corresponding information for the 32-bit library is given in the
2258    .\" HREF
2259    \fBpcre32\fP
2260    .\"
2261  page.  page.
2262  .P  .P
2263  When \fBpcre_exec()\fP returns either PCRE_ERROR_BADUTF8 or  When \fBpcre_exec()\fP returns either PCRE_ERROR_BADUTF8 or
# Line 2186  character. Line 2328  character.
2328  .sp  .sp
2329  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
2330  never occur in a valid UTF-8 string.  never occur in a valid UTF-8 string.
2331    .sp
2332      PCRE_UTF8_ERR2
2333    .sp
2334    Non-character. These are the last two characters in each plane (0xfffe, 0xffff,
2335    0x1fffe, 0x1ffff .. 0x10fffe, 0x10ffff), and the characters 0xfdd0..0xfdef.
2336  .  .
2337  .  .
2338  .SH "EXTRACTING CAPTURED SUBSTRINGS BY NUMBER"  .SH "EXTRACTING CAPTURED SUBSTRINGS BY NUMBER"
# Line 2622  When a recursive subpattern is processed Line 2769  When a recursive subpattern is processed
2769  recursively, using private vectors for \fIovector\fP and \fIworkspace\fP. This  recursively, using private vectors for \fIovector\fP and \fIworkspace\fP. This
2770  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
2771  extremely rare, as a vector of size 1000 is used.  extremely rare, as a vector of size 1000 is used.
2772    .sp
2773      PCRE_ERROR_DFA_BADRESTART (-30)
2774    .sp
2775    When \fBpcre_dfa_exec()\fP is called with the \fBPCRE_DFA_RESTART\fP option,
2776    some plausibility checks are made on the contents of the workspace, which
2777    should contain data about the previous partial match. If any of these checks
2778    fail, this error is given.
2779  .  .
2780  .  .
2781  .SH "SEE ALSO"  .SH "SEE ALSO"
2782  .rs  .rs
2783  .sp  .sp
2784  \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),
2785  \fBpcrematching\fP(3), \fBpcrepartial\fP(3), \fBpcreposix\fP(3),  \fBpcrecpp(3)\fP(3), \fBpcrematching\fP(3), \fBpcrepartial\fP(3),
2786  \fBpcreprecompile\fP(3), \fBpcresample\fP(3), \fBpcrestack\fP(3).  \fBpcreposix\fP(3), \fBpcreprecompile\fP(3), \fBpcresample\fP(3),
2787    \fBpcrestack\fP(3).
2788  .  .
2789  .  .
2790  .SH AUTHOR  .SH AUTHOR
# Line 2646  Cambridge CB2 3QH, England. Line 2801  Cambridge CB2 3QH, England.
2801  .rs  .rs
2802  .sp  .sp
2803  .nf  .nf
2804  Last updated: 22 February 2012  Last updated: 07 September 2012
2805  Copyright (c) 1997-2012 University of Cambridge.  Copyright (c) 1997-2012 University of Cambridge.
2806  .fi  .fi

Legend:
Removed from v.926  
changed lines
  Added in v.1113

  ViewVC Help
Powered by ViewVC 1.1.5