/[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 99 by ph10, Tue Mar 6 12:27:42 2007 UTC revision 211 by ph10, Thu Aug 9 09:52:43 2007 UTC
# Line 221  documentation. Line 221  documentation.
221  .SH NEWLINES  .SH NEWLINES
222  .rs  .rs
223  .sp  .sp
224  PCRE supports four different conventions for indicating line breaks in  PCRE supports five different conventions for indicating line breaks in
225  strings: a single CR (carriage return) character, a single LF (linefeed)  strings: a single CR (carriage return) character, a single LF (linefeed)
226  character, the two-character sequence CRLF, or any Unicode newline sequence.  character, the two-character sequence CRLF, any of the three preceding, or any
227  The Unicode newline sequences are the three just mentioned, plus the single  Unicode newline sequence. The Unicode newline sequences are the three just
228  characters VT (vertical tab, U+000B), FF (formfeed, U+000C), NEL (next line,  mentioned, plus the single characters VT (vertical tab, U+000B), FF (formfeed,
229  U+0085), LS (line separator, U+2028), and PS (paragraph separator, U+2029).  U+000C), NEL (next line, U+0085), LS (line separator, U+2028), and PS
230    (paragraph separator, U+2029).
231  .P  .P
232  Each of the first three conventions is used by at least one operating system as  Each of the first three conventions is used by at least one operating system as
233  its standard newline sequence. When PCRE is built, a default can be specified.  its standard newline sequence. When PCRE is built, a default can be specified.
# Line 264  which it was compiled. Details are given Line 265  which it was compiled. Details are given
265  .\" HREF  .\" HREF
266  \fBpcreprecompile\fP  \fBpcreprecompile\fP
267  .\"  .\"
268  documentation.  documentation. However, compiling a regular expression with one version of PCRE
269    for use with a different version is not guaranteed to work and may cause
270    crashes.
271  .  .
272  .  .
273  .SH "CHECKING BUILD-TIME OPTIONS"  .SH "CHECKING BUILD-TIME OPTIONS"
# Line 297  properties is available; otherwise it is Line 300  properties is available; otherwise it is
300  .sp  .sp
301  The output is an integer whose value specifies the default character sequence  The output is an integer whose value specifies the default character sequence
302  that is recognized as meaning "newline". The four values that are supported  that is recognized as meaning "newline". The four values that are supported
303  are: 10 for LF, 13 for CR, 3338 for CRLF, and -1 for ANY. The default should  are: 10 for LF, 13 for CR, 3338 for CRLF, -2 for ANYCRLF, and -1 for ANY. The
304  normally be the standard sequence for your operating system.  default should normally be the standard sequence for your operating system.
305  .sp  .sp
306    PCRE_CONFIG_LINK_SIZE    PCRE_CONFIG_LINK_SIZE
307  .sp  .sp
# Line 532  occurrences of ^ or $ in a pattern, sett Line 535  occurrences of ^ or $ in a pattern, sett
535    PCRE_NEWLINE_CR    PCRE_NEWLINE_CR
536    PCRE_NEWLINE_LF    PCRE_NEWLINE_LF
537    PCRE_NEWLINE_CRLF    PCRE_NEWLINE_CRLF
538      PCRE_NEWLINE_ANYCRLF
539    PCRE_NEWLINE_ANY    PCRE_NEWLINE_ANY
540  .sp  .sp
541  These options override the default newline definition that was chosen when PCRE  These options override the default newline definition that was chosen when PCRE
542  was built. Setting the first or the second specifies that a newline is  was built. Setting the first or the second specifies that a newline is
543  indicated by a single character (CR or LF, respectively). Setting  indicated by a single character (CR or LF, respectively). Setting
544  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
545  CRLF sequence. Setting PCRE_NEWLINE_ANY specifies that any Unicode newline  CRLF sequence. Setting PCRE_NEWLINE_ANYCRLF specifies that any of the three
546  sequence should be recognized. The Unicode newline sequences are the three just  preceding sequences should be recognized. Setting PCRE_NEWLINE_ANY specifies
547  mentioned, plus the single characters VT (vertical tab, U+000B), FF (formfeed,  that any Unicode newline sequence should be recognized. The Unicode newline
548  U+000C), NEL (next line, U+0085), LS (line separator, U+2028), and PS  sequences are the three just mentioned, plus the single characters VT (vertical
549  (paragraph separator, U+2029). The last two are recognized only in UTF-8 mode.  tab, U+000B), FF (formfeed, U+000C), NEL (next line, U+0085), LS (line
550    separator, U+2028), and PS (paragraph separator, U+2029). The last two are
551    recognized only in UTF-8 mode.
552  .P  .P
553  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
554  as a number, giving eight possibilities. Currently only five are used (default  as a number, giving eight possibilities. Currently only six are used (default
555  plus the four values above). This means that if you set more than one newline  plus the five values above). This means that if you set more than one newline
556  option, the combination may or may not be sensible. For example,  option, the combination may or may not be sensible. For example,
557  PCRE_NEWLINE_CR with PCRE_NEWLINE_LF is equivalent to PCRE_NEWLINE_CRLF, but  PCRE_NEWLINE_CR with PCRE_NEWLINE_LF is equivalent to PCRE_NEWLINE_CRLF, but
558  other combinations yield unused numbers and cause an error.  other combinations may yield unused numbers and cause an error.
559  .P  .P
560  The only time that a line break is specially recognized when compiling a  The only time that a line break is specially recognized when compiling a
561  pattern is if PCRE_EXTENDED is set, and an unescaped # outside a character  pattern is if PCRE_EXTENDED is set, and an unescaped # outside a character
# Line 595  page. Line 601  page.
601    PCRE_NO_UTF8_CHECK    PCRE_NO_UTF8_CHECK
602  .sp  .sp
603  When PCRE_UTF8 is set, the validity of the pattern as a UTF-8 string is  When PCRE_UTF8 is set, the validity of the pattern as a UTF-8 string is
604  automatically checked. If an invalid UTF-8 sequence of bytes is found,  automatically checked. There is a discussion about the
605  \fBpcre_compile()\fP returns an error. If you already know that your pattern is  .\" HTML <a href="pcre.html#utf8strings">
606  valid, and you want to skip this check for performance reasons, you can set the  .\" </a>
607  PCRE_NO_UTF8_CHECK option. When it is set, the effect of passing an invalid  validity of UTF-8 strings
608  UTF-8 string as a pattern is undefined. It may cause your program to crash.  .\"
609  Note that this option can also be passed to \fBpcre_exec()\fP and  in the main
610  \fBpcre_dfa_exec()\fP, to suppress the UTF-8 validity checking of subject  .\" HREF
611  strings.  \fBpcre\fP
612    .\"
613    page. If an invalid UTF-8 sequence of bytes is found, \fBpcre_compile()\fP
614    returns an error. If you already know that your pattern is valid, and you want
615    to skip this check for performance reasons, you can set the PCRE_NO_UTF8_CHECK
616    option. When it is set, the effect of passing an invalid UTF-8 string as a
617    pattern is undefined. It may cause your program to crash. Note that this option
618    can also be passed to \fBpcre_exec()\fP and \fBpcre_dfa_exec()\fP, to suppress
619    the UTF-8 validity checking of subject strings.
620  .  .
621  .  .
622  .SH "COMPILATION ERROR CODES"  .SH "COMPILATION ERROR CODES"
# Line 642  out of use. To avoid confusion, they hav Line 656  out of use. To avoid confusion, they hav
656    26  malformed number or name after (?(    26  malformed number or name after (?(
657    27  conditional group contains more than two branches    27  conditional group contains more than two branches
658    28  assertion expected after (?(    28  assertion expected after (?(
659    29  (?R or (?digits must be followed by )    29  (?R or (?[+-]digits must be followed by )
660    30  unknown POSIX class name    30  unknown POSIX class name
661    31  POSIX collating elements are not supported    31  POSIX collating elements are not supported
662    32  this version of PCRE is not compiled with PCRE_UTF8 support    32  this version of PCRE is not compiled with PCRE_UTF8 support
# Line 663  out of use. To avoid confusion, they hav Line 677  out of use. To avoid confusion, they hav
677    47  unknown property name after \eP or \ep    47  unknown property name after \eP or \ep
678    48  subpattern name is too long (maximum 32 characters)    48  subpattern name is too long (maximum 32 characters)
679    49  too many named subpatterns (maximum 10,000)    49  too many named subpatterns (maximum 10,000)
680    50  repeated subpattern is too long    50  [this code is not in use]
681    51  octal value is greater than \e377 (not in UTF-8 mode)    51  octal value is greater than \e377 (not in UTF-8 mode)
682    52  internal error: overran compiling workspace    52  internal error: overran compiling workspace
683    53  internal error: previously-checked referenced subpattern not found    53  internal error: previously-checked referenced subpattern not found
684    54  DEFINE group contains more than one branch    54  DEFINE group contains more than one branch
685    55  repeating a DEFINE group is not allowed    55  repeating a DEFINE group is not allowed
686    56  inconsistent NEWLINE options"    56  inconsistent NEWLINE options"
687      57  \eg is not followed by a braced name or an optionally braced
688            non-zero number
689      58  (?+ or (?- or (?(+ or (?(- must be followed by a non-zero number
690  .  .
691  .  .
692  .SH "STUDYING A PATTERN"  .SH "STUDYING A PATTERN"
# Line 729  bytes is created. Line 746  bytes is created.
746  .SH "LOCALE SUPPORT"  .SH "LOCALE SUPPORT"
747  .rs  .rs
748  .sp  .sp
749  PCRE handles caseless matching, and determines whether characters are letters  PCRE handles caseless matching, and determines whether characters are letters,
750  digits, or whatever, by reference to a set of tables, indexed by character  digits, or whatever, by reference to a set of tables, indexed by character
751  value. When running in UTF-8 mode, this applies only to characters with codes  value. When running in UTF-8 mode, this applies only to characters with codes
752  less than 128. Higher-valued codes never match escapes such as \ew or \ed, but  less than 128. Higher-valued codes never match escapes such as \ew or \ed, but
753  can be tested with \ep if PCRE is built with Unicode character property  can be tested with \ep if PCRE is built with Unicode character property
754  support. The use of locales with Unicode is discouraged.  support. The use of locales with Unicode is discouraged. If you are handling
755  .P  characters with codes greater than 128, you should either use UTF-8 and
756  An internal set of tables is created in the default C locale when PCRE is  Unicode, or use locales, but not try to mix the two.
757  built. This is used when the final argument of \fBpcre_compile()\fP is NULL,  .P
758  and is sufficient for many applications. An alternative set of tables can,  PCRE contains an internal set of tables that are used when the final argument
759  however, be supplied. These may be created in a different locale from the  of \fBpcre_compile()\fP is NULL. These are sufficient for many applications.
760  default. As more and more applications change to using Unicode, the need for  Normally, the internal tables recognize only ASCII characters. However, when
761  this locale support is expected to die away.  PCRE is built, it is possible to cause the internal tables to be rebuilt in the
762    default "C" locale of the local system, which may cause them to be different.
763    .P
764    The internal tables can always be overridden by tables supplied by the
765    application that calls PCRE. These may be created in a different locale from
766    the default. As more and more applications change to using Unicode, the need
767    for this locale support is expected to die away.
768  .P  .P
769  External tables are built by calling the \fBpcre_maketables()\fP function,  External tables are built by calling the \fBpcre_maketables()\fP function,
770  which has no arguments, in the relevant locale. The result can then be passed  which has no arguments, in the relevant locale. The result can then be passed
# Line 754  the following code could be used: Line 777  the following code could be used:
777    tables = pcre_maketables();    tables = pcre_maketables();
778    re = pcre_compile(..., tables);    re = pcre_compile(..., tables);
779  .sp  .sp
780    The locale name "fr_FR" is used on Linux and other Unix-like systems; if you
781    are using Windows, the name for the French locale is "french".
782    .P
783  When \fBpcre_maketables()\fP runs, the tables are built in memory that is  When \fBpcre_maketables()\fP runs, the tables are built in memory that is
784  obtained via \fBpcre_malloc\fP. It is the caller's responsibility to ensure  obtained via \fBpcre_malloc\fP. It is the caller's responsibility to ensure
785  that the memory containing the tables remains available for as long as it is  that the memory containing the tables remains available for as long as it is
# Line 856  table indicating a fixed set of bytes fo Line 882  table indicating a fixed set of bytes fo
882  string, a pointer to the table is returned. Otherwise NULL is returned. The  string, a pointer to the table is returned. Otherwise NULL is returned. The
883  fourth argument should point to an \fBunsigned char *\fP variable.  fourth argument should point to an \fBunsigned char *\fP variable.
884  .sp  .sp
885      PCRE_INFO_JCHANGED
886    .sp
887    Return 1 if the (?J) option setting is used in the pattern, otherwise 0. The
888    fourth argument should point to an \fBint\fP variable. The (?J) internal option
889    setting changes the local PCRE_DUPNAMES option.
890    .sp
891    PCRE_INFO_LASTLITERAL    PCRE_INFO_LASTLITERAL
892  .sp  .sp
893  Return the value of the rightmost literal byte that must exist in any matched  Return the value of the rightmost literal byte that must exist in any matched
# Line 908  When writing code to extract data from n Line 940  When writing code to extract data from n
940  name-to-number map, remember that the length of the entries is likely to be  name-to-number map, remember that the length of the entries is likely to be
941  different for each compiled pattern.  different for each compiled pattern.
942  .sp  .sp
943      PCRE_INFO_OKPARTIAL
944    .sp
945    Return 1 if the pattern can be used for partial matching, otherwise 0. The
946    fourth argument should point to an \fBint\fP variable. The
947    .\" HREF
948    \fBpcrepartial\fP
949    .\"
950    documentation lists the restrictions that apply to patterns when partial
951    matching is used.
952    .sp
953    PCRE_INFO_OPTIONS    PCRE_INFO_OPTIONS
954  .sp  .sp
955  Return a copy of the options with which the pattern was compiled. The fourth  Return a copy of the options with which the pattern was compiled. The fourth
956  argument should point to an \fBunsigned long int\fP variable. These option bits  argument should point to an \fBunsigned long int\fP variable. These option bits
957  are those specified in the call to \fBpcre_compile()\fP, modified by any  are those specified in the call to \fBpcre_compile()\fP, modified by any
958  top-level option settings within the pattern itself.  top-level option settings at the start of the pattern itself. In other words,
959    they are the options that will be in force when matching starts. For example,
960    if the pattern /(?im)abc(?-i)d/ is compiled with the PCRE_EXTENDED option, the
961    result is PCRE_CASELESS, PCRE_MULTILINE, and PCRE_EXTENDED.
962  .P  .P
963  A pattern is automatically anchored by PCRE if all of its top-level  A pattern is automatically anchored by PCRE if all of its top-level
964  alternatives begin with one of the following:  alternatives begin with one of the following:
# Line 1141  matching time. Line 1186  matching time.
1186    PCRE_NEWLINE_CR    PCRE_NEWLINE_CR
1187    PCRE_NEWLINE_LF    PCRE_NEWLINE_LF
1188    PCRE_NEWLINE_CRLF    PCRE_NEWLINE_CRLF
1189      PCRE_NEWLINE_ANYCRLF
1190    PCRE_NEWLINE_ANY    PCRE_NEWLINE_ANY
1191  .sp  .sp
1192  These options override the newline definition that was chosen or defaulted when  These options override the newline definition that was chosen or defaulted when
# Line 1148  the pattern was compiled. For details, s Line 1194  the pattern was compiled. For details, s
1194  \fBpcre_compile()\fP above. During matching, the newline choice affects the  \fBpcre_compile()\fP above. During matching, the newline choice affects the
1195  behaviour of the dot, circumflex, and dollar metacharacters. It may also alter  behaviour of the dot, circumflex, and dollar metacharacters. It may also alter
1196  the way the match position is advanced after a match failure for an unanchored  the way the match position is advanced after a match failure for an unanchored
1197  pattern. When PCRE_NEWLINE_CRLF or PCRE_NEWLINE_ANY is set, and a match attempt  pattern. When PCRE_NEWLINE_CRLF, PCRE_NEWLINE_ANYCRLF, or PCRE_NEWLINE_ANY is
1198  fails when the current position is at a CRLF sequence, the match position is  set, and a match attempt fails when the current position is at a CRLF sequence,
1199  advanced by two characters instead of one, in other words, to after the CRLF.  the match position is advanced by two characters instead of one, in other
1200    words, to after the CRLF.
1201  .sp  .sp
1202    PCRE_NOTBOL    PCRE_NOTBOL
1203  .sp  .sp
# Line 1193  code that demonstrates how to do this in Line 1240  code that demonstrates how to do this in
1240  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
1241  string is automatically checked when \fBpcre_exec()\fP is subsequently called.  string is automatically checked when \fBpcre_exec()\fP is subsequently called.
1242  The value of \fIstartoffset\fP is also checked to ensure that it points to the  The value of \fIstartoffset\fP is also checked to ensure that it points to the
1243  start of a UTF-8 character. If an invalid UTF-8 sequence of bytes is found,  start of a UTF-8 character. There is a discussion about the validity of UTF-8
1244  \fBpcre_exec()\fP returns the error PCRE_ERROR_BADUTF8. If \fIstartoffset\fP  strings in the
1245  contains an invalid value, PCRE_ERROR_BADUTF8_OFFSET is returned.  .\" HTML <a href="pcre.html#utf8strings">
1246    .\" </a>
1247    section on UTF-8 support
1248    .\"
1249    in the main
1250    .\" HREF
1251    \fBpcre\fP
1252    .\"
1253    page. If an invalid UTF-8 sequence of bytes is found, \fBpcre_exec()\fP returns
1254    the error PCRE_ERROR_BADUTF8. If \fIstartoffset\fP contains an invalid value,
1255    PCRE_ERROR_BADUTF8_OFFSET is returned.
1256  .P  .P
1257  If you already know that your subject is valid, and you want to skip these  If you already know that your subject is valid, and you want to skip these
1258  checks for performance reasons, you can set the PCRE_NO_UTF8_CHECK option when  checks for performance reasons, you can set the PCRE_NO_UTF8_CHECK option when
# Line 1427  The internal recursion limit, as specifi Line 1484  The internal recursion limit, as specifi
1484  field in a \fBpcre_extra\fP structure (or defaulted) was reached. See the  field in a \fBpcre_extra\fP structure (or defaulted) was reached. See the
1485  description above.  description above.
1486  .sp  .sp
   PCRE_ERROR_NULLWSLIMIT    (-22)  
 .sp  
 When a group that can match an empty substring is repeated with an unbounded  
 upper limit, the subject position at the start of the group must be remembered,  
 so that a test for an empty string can be made when the end of the group is  
 reached. Some workspace is required for this; if it runs out, this error is  
 given.  
 .sp  
1487    PCRE_ERROR_BADNEWLINE     (-23)    PCRE_ERROR_BADNEWLINE     (-23)
1488  .sp  .sp
1489  An invalid combination of PCRE_NEWLINE_\fIxxx\fP options was given.  An invalid combination of PCRE_NEWLINE_\fIxxx\fP options was given.
1490  .P  .P
1491  Error numbers -16 to -20 are not used by \fBpcre_exec()\fP.  Error numbers -16 to -20 and -22 are not used by \fBpcre_exec()\fP.
1492  .  .
1493  .  .
1494  .SH "EXTRACTING CAPTURED SUBSTRINGS BY NUMBER"  .SH "EXTRACTING CAPTURED SUBSTRINGS BY NUMBER"
# Line 1585  pattern. This is needed in order to gain Line 1634  pattern. This is needed in order to gain
1634  translation table.  translation table.
1635  .P  .P
1636  These functions call \fBpcre_get_stringnumber()\fP, and if it succeeds, they  These functions call \fBpcre_get_stringnumber()\fP, and if it succeeds, they
1637  then call \fIpcre_copy_substring()\fP or \fIpcre_get_substring()\fP, as  then call \fBpcre_copy_substring()\fP or \fBpcre_get_substring()\fP, as
1638  appropriate.  appropriate. \fBNOTE:\fP If PCRE_DUPNAMES is set and there are duplicate names,
1639    the behaviour may not be what you want (see the next section).
1640  .  .
1641  .  .
1642  .SH "DUPLICATE SUBPATTERN NAMES"  .SH "DUPLICATE SUBPATTERN NAMES"
# Line 1603  example is shown in the Line 1653  example is shown in the
1653  .\" HREF  .\" HREF
1654  \fBpcrepattern\fP  \fBpcrepattern\fP
1655  .\"  .\"
1656  documentation. When duplicates are present, \fBpcre_copy_named_substring()\fP  documentation.
1657  and \fBpcre_get_named_substring()\fP return the first substring corresponding  .P
1658  to the given name that is set. If none are set, an empty string is returned.  When duplicates are present, \fBpcre_copy_named_substring()\fP and
1659  The \fBpcre_get_stringnumber()\fP function returns one of the numbers that are  \fBpcre_get_named_substring()\fP return the first substring corresponding to
1660  associated with the name, but it is not defined which it is.  the given name that is set. If none are set, PCRE_ERROR_NOSUBSTRING (-7) is
1661  .sp  returned; no data is returned. The \fBpcre_get_stringnumber()\fP function
1662    returns one of the numbers that are associated with the name, but it is not
1663    defined which it is.
1664    .P
1665  If you want to get full details of all captured substrings for a given name,  If you want to get full details of all captured substrings for a given name,
1666  you must use the \fBpcre_get_stringtable_entries()\fP function. The first  you must use the \fBpcre_get_stringtable_entries()\fP function. The first
1667  argument is the compiled pattern, and the second is the name. The third and  argument is the compiled pattern, and the second is the name. The third and
# Line 1833  Cambridge CB2 3QH, England. Line 1886  Cambridge CB2 3QH, England.
1886  .rs  .rs
1887  .sp  .sp
1888  .nf  .nf
1889  Last updated: 06 March 2007  Last updated: 09 August 2007
1890  Copyright (c) 1997-2007 University of Cambridge.  Copyright (c) 1997-2007 University of Cambridge.
1891  .fi  .fi

Legend:
Removed from v.99  
changed lines
  Added in v.211

  ViewVC Help
Powered by ViewVC 1.1.5