/[pcre]/code/trunk/doc/pcre.txt

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-revision 185 by ph10,
Tue Jun 19 13:39:46 2007 UTC
+revision 211 by ph10,
Thu Aug  9 09:52:43 2007 UTC
 Line 45 
 INTRODUCTION
         Details of exactly which Perl regular expression features are  and  are
         not supported by PCRE are given in separate documents. See the pcrepat-
-        tern and pcrecompat pages.
+        tern and pcrecompat pages. There is a syntax summary in the  pcresyntax
+        page.
-        Some features of PCRE can be included, excluded, or  changed  when  the
+        Some  features  of  PCRE can be included, excluded, or changed when the
-        library  is  built.  The pcre_config() function makes it possible for a
+        library is built. The pcre_config() function makes it  possible  for  a
-        client to discover which features are  available.  The  features  them-
+        client  to  discover  which  features are available. The features them-
-        selves  are described in the pcrebuild page. Documentation about build-
+        selves are described in the pcrebuild page. Documentation about  build-
-        ing PCRE for various operating systems can be found in the README  file
+        ing  PCRE for various operating systems can be found in the README file
         in the source distribution.
-        The  library  contains  a number of undocumented internal functions and
+        The library contains a number of undocumented  internal  functions  and
-        data tables that are used by more than one  of  the  exported  external
+        data  tables  that  are  used by more than one of the exported external
-        functions,  but  which  are  not  intended for use by external callers.
+        functions, but which are not intended  for  use  by  external  callers.
-        Their names all begin with "_pcre_", which hopefully will  not  provoke
+        Their  names  all begin with "_pcre_", which hopefully will not provoke
         any name clashes. In some environments, it is possible to control which
-        external symbols are exported when a shared library is  built,  and  in
+        external  symbols  are  exported when a shared library is built, and in
         these cases the undocumented symbols are not exported.
  USER DOCUMENTATION
-        The  user  documentation  for PCRE comprises a number of different sec-
+        The user documentation for PCRE comprises a number  of  different  sec-
-        tions. In the "man" format, each of these is a separate "man page".  In
+        tions.  In the "man" format, each of these is a separate "man page". In
-        the  HTML  format, each is a separate page, linked from the index page.
+        the HTML format, each is a separate page, linked from the  index  page.
-        In the plain text format, all the sections are concatenated,  for  ease
+        In  the  plain text format, all the sections are concatenated, for ease
         of searching. The sections are as follows:
           pcre              this document
-Line 83 
 USER DOCUMENTATION
+Line 84 
 USER DOCUMENTATION
           pcrepartial       details of the partial matching facility
           pcrepattern       syntax and semantics of supported
                               regular expressions
+          pcresyntax        quick syntax reference
           pcreperform       discussion of performance issues
           pcreposix         the POSIX-compatible C API
           pcreprecompile    details of saving and re-using precompiled patterns
-Line 90 
 USER DOCUMENTATION
+Line 92 
 USER DOCUMENTATION
           pcrestack         discussion of stack usage
           pcretest          description of the pcretest testing command
-        In addition, in the "man" and HTML formats, there is a short  page  for
+        In  addition,  in the "man" and HTML formats, there is a short page for
         each C library function, listing its arguments and results.
  LIMITATIONS
-        There  are some size limitations in PCRE but it is hoped that they will
+        There are some size limitations in PCRE but it is hoped that they  will
         never in practice be relevant.
-        The maximum length of a compiled pattern is 65539 (sic) bytes  if  PCRE
+        The  maximum  length of a compiled pattern is 65539 (sic) bytes if PCRE
         is compiled with the default internal linkage size of 2. If you want to
-        process regular expressions that are truly enormous,  you  can  compile
+        process  regular  expressions  that are truly enormous, you can compile
-        PCRE  with  an  internal linkage size of 3 or 4 (see the README file in
+        PCRE with an internal linkage size of 3 or 4 (see the  README  file  in
-        the source distribution and the pcrebuild documentation  for  details).
+        the  source  distribution and the pcrebuild documentation for details).
-        In  these  cases the limit is substantially larger.  However, the speed
+        In these cases the limit is substantially larger.  However,  the  speed
         of execution is slower.
-        All values in repeating quantifiers must be less than 65536. The  maxi-
+        All values in repeating quantifiers must be less than 65536.
-        mum  compiled  length  of  subpattern  with an explicit repeat count is
-bytes. The maximum number of capturing subpatterns is 65535.
         There is no limit to the number of parenthesized subpatterns, but there
         can be no more than 65535 capturing subpatterns.
 Line 117 
 LIMITATIONS
         The maximum length of name for a named subpattern is 32 characters, and
         the maximum number of named subpatterns is 10000.
-        The maximum length of a subject string is the largest  positive  number
+        The  maximum  length of a subject string is the largest positive number
-        that  an integer variable can hold. However, when using the traditional
+        that an integer variable can hold. However, when using the  traditional
         matching function, PCRE uses recursion to handle subpatterns and indef-
-        inite  repetition.  This means that the available stack space may limit
+        inite repetition.  This means that the available stack space may  limit
         the size of a subject string that can be processed by certain patterns.
         For a discussion of stack issues, see the pcrestack documentation.
  UTF-8 AND UNICODE PROPERTY SUPPORT
-        From  release  3.3,  PCRE  has  had  some support for character strings
+        From release 3.3, PCRE has  had  some  support  for  character  strings
-        encoded in the UTF-8 format. For release 4.0 this was greatly  extended
+        encoded  in the UTF-8 format. For release 4.0 this was greatly extended
-        to  cover  most common requirements, and in release 5.0 additional sup-
+        to cover most common requirements, and in release 5.0  additional  sup-
         port for Unicode general category properties was added.
-        In order process UTF-8 strings, you must build PCRE  to  include  UTF-8
+        In  order  process  UTF-8 strings, you must build PCRE to include UTF-8
-        support  in  the  code,  and, in addition, you must call pcre_compile()
+        support in the code, and, in addition,  you  must  call  pcre_compile()
-        with the PCRE_UTF8 option flag. When you do this, both the pattern  and
+        with  the PCRE_UTF8 option flag. When you do this, both the pattern and
-        any  subject  strings  that are matched against it are treated as UTF-8
+        any subject strings that are matched against it are  treated  as  UTF-8
         strings instead of just strings of bytes.
-        If you compile PCRE with UTF-8 support, but do not use it at run  time,
+        If  you compile PCRE with UTF-8 support, but do not use it at run time,
-        the  library will be a bit bigger, but the additional run time overhead
+        the library will be a bit bigger, but the additional run time  overhead
         is limited to testing the PCRE_UTF8 flag occasionally, so should not be
         very big.
         If PCRE is built with Unicode character property support (which implies
-        UTF-8 support), the escape sequences \p{..}, \P{..}, and  \X  are  sup-
+        UTF-8  support),  the  escape sequences \p{..}, \P{..}, and \X are sup-
         ported.  The available properties that can be tested are limited to the
-        general category properties such as Lu for an upper case letter  or  Nd
+        general  category  properties such as Lu for an upper case letter or Nd
-        for  a  decimal number, the Unicode script names such as Arabic or Han,
+        for a decimal number, the Unicode script names such as Arabic  or  Han,
-        and the derived properties Any and L&. A full  list  is  given  in  the
+        and  the  derived  properties  Any  and L&. A full list is given in the
         pcrepattern documentation. Only the short names for properties are sup-
-        ported. For example, \p{L} matches a letter. Its Perl synonym,  \p{Let-
+        ported.  For example, \p{L} matches a letter. Its Perl synonym, \p{Let-
-        ter},  is  not  supported.   Furthermore,  in Perl, many properties may
+        ter}, is not supported.  Furthermore,  in  Perl,  many  properties  may
-        optionally be prefixed by "Is", for compatibility with Perl  5.6.  PCRE
+        optionally  be  prefixed by "Is", for compatibility with Perl 5.6. PCRE
         does not support this.
-        The following comments apply when PCRE is running in UTF-8 mode:
+    Validity of UTF-8 strings
+        When you set the PCRE_UTF8 flag, the strings  passed  as  patterns  and
+        subjects are (by default) checked for validity on entry to the relevant
+        functions. From release 7.3 of PCRE, the check is according  the  rules
+        of  RFC  3629, which are themselves derived from the Unicode specifica-
+        tion. Earlier releases of PCRE followed the rules of  RFC  2279,  which
+        allows  the  full range of 31-bit values (0 to 0x7FFFFFFF). The current
+        check allows only values in the range U+0 to U+10FFFF, excluding U+D800
+        to U+DFFF.
+        The  excluded  code  points are the "Low Surrogate Area" of Unicode, of
+        which the Unicode Standard says this: "The Low Surrogate Area does  not
+        contain  any  character  assignments,  consequently  no  character code
+        charts or namelists are provided for this area. Surrogates are reserved
+        for  use  with  UTF-16 and then must be used in pairs." The code points
+        that are encoded by UTF-16 pairs  are  available  as  independent  code
+        points  in  the  UTF-8  encoding.  (In other words, the whole surrogate
+        thing is a fudge for UTF-16 which unfortunately messes up UTF-8.)
+        If an  invalid  UTF-8  string  is  passed  to  PCRE,  an  error  return
+        (PCRE_ERROR_BADUTF8) is given. In some situations, you may already know
+        that your strings are valid, and therefore want to skip these checks in
+        order to improve performance. If you set the PCRE_NO_UTF8_CHECK flag at
+        compile time or at run time, PCRE assumes that the pattern  or  subject
+        it  is  given  (respectively)  contains only valid UTF-8 codes. In this
+        case, it does not diagnose an invalid UTF-8 string.
+        If you pass an invalid UTF-8 string  when  PCRE_NO_UTF8_CHECK  is  set,
+        what  happens  depends on why the string is invalid. If the string con-
+        forms to the "old" definition of UTF-8 (RFC 2279), it is processed as a
+        string  of  characters  in  the  range 0 to 0x7FFFFFFF. In other words,
+        apart from the initial validity test, PCRE (when in UTF-8 mode) handles
+        strings  according  to  the more liberal rules of RFC 2279. However, if
+        the string does not even conform to RFC 2279, the result is  undefined.
+        Your program may crash.
+        If  you  want  to  process  strings  of  values  in the full range 0 to
+x7FFFFFFF, encoded in a UTF-8-like manner as per the old RFC, you  can
+        set PCRE_NO_UTF8_CHECK to bypass the more restrictive test. However, in
+        this situation, you will have to apply your own validity check.
-.  When you set the PCRE_UTF8 flag, the strings passed as patterns and
+    General comments about UTF-8 mode
-        subjects are checked for validity on entry to the  relevant  functions.
-        If an invalid UTF-8 string is passed, an error return is given. In some
-        situations, you may already know  that  your  strings  are  valid,  and
-        therefore want to skip these checks in order to improve performance. If
-        you set the PCRE_NO_UTF8_CHECK flag at compile time  or  at  run  time,
-        PCRE  assumes  that  the  pattern or subject it is given (respectively)
-        contains only valid UTF-8 codes. In this case, it does not diagnose  an
-        invalid  UTF-8 string. If you pass an invalid UTF-8 string to PCRE when
-        PCRE_NO_UTF8_CHECK is set, the results are undefined. Your program  may
-        crash.
-.  An  unbraced  hexadecimal  escape sequence (such as \xb3) matches a
+. An unbraced hexadecimal escape sequence (such  as  \xb3)  matches  a
         two-byte UTF-8 character if the value is greater than 127.
-. Octal numbers up to \777 are recognized, and  match  two-byte  UTF-8
+.  Octal  numbers  up to \777 are recognized, and match two-byte UTF-8
         characters for values greater than \177.
-.  Repeat quantifiers apply to complete UTF-8 characters, not to indi-
+. Repeat quantifiers apply to complete UTF-8 characters, not to  indi-
         vidual bytes, for example: \x{100}{3}.
-. The dot metacharacter matches one UTF-8 character instead of a  sin-
+.  The dot metacharacter matches one UTF-8 character instead of a sin-
         gle byte.
-.  The  escape sequence \C can be used to match a single byte in UTF-8
+. The escape sequence \C can be used to match a single byte  in  UTF-8
-        mode, but its use can lead to some strange effects.  This  facility  is
+        mode,  but  its  use can lead to some strange effects. This facility is
         not available in the alternative matching function, pcre_dfa_exec().
-.  The  character escapes \b, \B, \d, \D, \s, \S, \w, and \W correctly
+. The character escapes \b, \B, \d, \D, \s, \S, \w, and  \W  correctly
-        test characters of any code value, but the characters that PCRE  recog-
+        test  characters of any code value, but the characters that PCRE recog-
-        nizes  as  digits,  spaces,  or  word characters remain the same set as
+        nizes as digits, spaces, or word characters  remain  the  same  set  as
         before, all with values less than 256. This remains true even when PCRE
-        includes  Unicode  property support, because to do otherwise would slow
+        includes Unicode property support, because to do otherwise  would  slow
-        down PCRE in many common cases. If you really want to test for a  wider
+        down  PCRE in many common cases. If you really want to test for a wider
-        sense  of,  say,  "digit",  you must use Unicode property tests such as
+        sense of, say, "digit", you must use Unicode  property  tests  such  as
         \p{Nd}.
-. Similarly, characters that match the POSIX named  character  classes
+.  Similarly,  characters that match the POSIX named character classes
         are all low-valued characters.
-.  However,  the Perl 5.10 horizontal and vertical whitespace matching
+. However, the Perl 5.10 horizontal and vertical  whitespace  matching
         escapes (\h, \H, \v, and \V) do match all the appropriate Unicode char-
         acters.
-.  Case-insensitive  matching applies only to characters whose values
+. Case-insensitive matching applies only to  characters  whose  values
-        are less than 128, unless PCRE is built with Unicode property  support.
+        are  less than 128, unless PCRE is built with Unicode property support.
-        Even  when  Unicode  property support is available, PCRE still uses its
+        Even when Unicode property support is available, PCRE  still  uses  its
-        own character tables when checking the case of  low-valued  characters,
+        own  character  tables when checking the case of low-valued characters,
-        so  as not to degrade performance.  The Unicode property information is
+        so as not to degrade performance.  The Unicode property information  is
         used only for characters with higher values. Even when Unicode property
         support is available, PCRE supports case-insensitive matching only when
-        there is a one-to-one mapping between a letter's  cases.  There  are  a
+        there  is  a  one-to-one  mapping between a letter's cases. There are a
-        small  number  of  many-to-one  mappings in Unicode; these are not sup-
+        small number of many-to-one mappings in Unicode;  these  are  not  sup-
         ported by PCRE.
-Line 219 
 AUTHOR
+Line 249 
 AUTHOR
         University Computing Service
         Cambridge CB2 3QH, England.
-        Putting an actual email address here seems to have been a spam  magnet,
+        Putting  an actual email address here seems to have been a spam magnet,
-        so  I've  taken  it away. If you want to email me, use my two initials,
+        so I've taken it away. If you want to email me, use  my  two  initials,
         followed by the two digits 10, at the domain cam.ac.uk.
  REVISION
-        Last updated: 13 June 2007
+        Last updated: 09 August 2007
         Copyright (c) 1997-2007 University of Cambridge.
  ------------------------------------------------------------------------------
-Line 459 
 USING EBCDIC CODE
+Line 489 
 USING EBCDIC CODE
         PCRE  assumes  by  default that it will run in an environment where the
         character code is ASCII (or Unicode, which is  a  superset  of  ASCII).
-        PCRE  can,  however,  be  compiled  to  run in an EBCDIC environment by
+        This  is  the  case for most computer operating systems. PCRE can, how-
-        adding
+        ever, be compiled to run in an EBCDIC environment by adding
           --enable-ebcdic
         to the configure command. This setting implies --enable-rebuild-charta-
-        bles.
+        bles.  You  should  only  use  it if you know that you are in an EBCDIC
+        environment (for example, an IBM mainframe operating system).
  SEE ALSO
-Line 482 
 AUTHOR
+Line 513 
 AUTHOR
  REVISION
-        Last updated: 05 June 2007
+        Last updated: 30 July 2007
         Copyright (c) 1997-2007 University of Cambridge.
  ------------------------------------------------------------------------------
-Line 626 
 THE ALTERNATIVE MATCHING ALGORITHM
+Line 657 
 THE ALTERNATIVE MATCHING ALGORITHM
 .  Callouts  are  supported, but the value of the capture_top field is
         always 1, and the value of the capture_last field is always -1.
-.  The \C escape sequence, which (in the standard algorithm) matches a
+. The \C escape sequence, which (in the standard algorithm) matches  a
         single  byte, even in UTF-8 mode, is not supported because the alterna-
         tive algorithm moves through the subject  string  one  character  at  a
         time, for all active paths through the tree.
+.  None  of  the  backtracking control verbs such as (*PRUNE) are sup-
+        ported.
  ADVANTAGES OF THE ALTERNATIVE ALGORITHM
-        Using  the alternative matching algorithm provides the following advan-
+        Using the alternative matching algorithm provides the following  advan-
         tages:
 . All possible matches (at a single point in the subject) are automat-
-        ically  found,  and  in particular, the longest match is found. To find
+        ically found, and in particular, the longest match is  found.  To  find
         more than one match using the standard algorithm, you have to do kludgy
         things with callouts.
-.  There is much better support for partial matching. The restrictions
+. There is much better support for partial matching. The  restrictions
-        on the content of the pattern that apply when using the standard  algo-
+        on  the content of the pattern that apply when using the standard algo-
-        rithm  for  partial matching do not apply to the alternative algorithm.
+        rithm for partial matching do not apply to the  alternative  algorithm.
-        For non-anchored patterns, the starting position of a partial match  is
+        For  non-anchored patterns, the starting position of a partial match is
         available.
-.  Because  the  alternative  algorithm  scans the subject string just
+. Because the alternative algorithm  scans  the  subject  string  just
-        once, and never needs to backtrack, it is possible to  pass  very  long
+        once,  and  never  needs to backtrack, it is possible to pass very long
-        subject  strings  to  the matching function in several pieces, checking
+        subject strings to the matching function in  several  pieces,  checking
         for partial matching each time.
-Line 658 
 DISADVANTAGES OF THE ALTERNATIVE ALGORIT
+Line 692 
 DISADVANTAGES OF THE ALTERNATIVE ALGORIT
         The alternative algorithm suffers from a number of disadvantages:
-. It is substantially slower than  the  standard  algorithm.  This  is
+.  It  is  substantially  slower  than the standard algorithm. This is
-        partly  because  it has to search for all possible matches, but is also
+        partly because it has to search for all possible matches, but  is  also
         because it is less susceptible to optimization.
 . Capturing parentheses and back references are not supported.
-Line 677 
 AUTHOR
+Line 711 
 AUTHOR
  REVISION
-        Last updated: 29 May 2007
+        Last updated: 08 August 2007
         Copyright (c) 1997-2007 University of Cambridge.
  ------------------------------------------------------------------------------
-Line 1221 
 COMPILING A PATTERN
+Line 1255 
 COMPILING A PATTERN
           PCRE_NO_UTF8_CHECK
         When PCRE_UTF8 is set, the validity of the pattern as a UTF-8 string is
-        automatically  checked. If an invalid UTF-8 sequence of bytes is found,
+        automatically  checked.  There  is  a  discussion about the validity of
-        pcre_compile() returns an error. If you already know that your  pattern
+        UTF-8 strings in the main pcre page. If an invalid  UTF-8  sequence  of
-        is  valid, and you want to skip this check for performance reasons, you
+        bytes  is  found,  pcre_compile() returns an error. If you already know
-        can set the PCRE_NO_UTF8_CHECK option. When it is set,  the  effect  of
+        that your pattern is valid, and you want to skip this check for perfor-
-        passing an invalid UTF-8 string as a pattern is undefined. It may cause
+        mance  reasons,  you  can set the PCRE_NO_UTF8_CHECK option. When it is
-        your program to crash.  Note that this option can  also  be  passed  to
+        set, the effect of passing an invalid UTF-8  string  as  a  pattern  is
-        pcre_exec()  and pcre_dfa_exec(), to suppress the UTF-8 validity check-
+        undefined.  It  may  cause your program to crash. Note that this option
-        ing of subject strings.
+        can also be passed to pcre_exec() and pcre_dfa_exec(), to suppress  the
+        UTF-8 validity checking of subject strings.
  COMPILATION ERROR CODES
-        The following table lists the error  codes  than  may  be  returned  by
+        The  following  table  lists  the  error  codes than may be returned by
-        pcre_compile2(),  along with the error messages that may be returned by
+        pcre_compile2(), along with the error messages that may be returned  by
-        both compiling functions. As PCRE has developed, some error codes  have
+        both  compiling functions. As PCRE has developed, some error codes have
         fallen out of use. To avoid confusion, they have not been re-used.
  no error
-Line 1288 
 COMPILATION ERROR CODES
+Line 1323 
 COMPILATION ERROR CODES
  unknown property name after \P or \p
  subpattern name is too long (maximum 32 characters)
  too many named subpatterns (maximum 10,000)
- repeated subpattern is too long
+ [this code is not in use]
  octal value is greater than \377 (not in UTF-8 mode)
  internal error: overran compiling workspace
-  internal  error:  previously-checked  referenced  subpattern not
+ internal  error:  previously-checked  referenced  subpattern  not
         found
  DEFINE group contains more than one branch
  repeating a DEFINE group is not allowed
-Line 1306 
 STUDYING A PATTERN
+Line 1341 
 STUDYING A PATTERN
         pcre_extra *pcre_study(const pcre *code, int options
              const char **errptr);
-        If a compiled pattern is going to be used several times,  it  is  worth
+        If  a  compiled  pattern is going to be used several times, it is worth
         spending more time analyzing it in order to speed up the time taken for
-        matching. The function pcre_study() takes a pointer to a compiled  pat-
+        matching.  The function pcre_study() takes a pointer to a compiled pat-
         tern as its first argument. If studying the pattern produces additional
-        information that will help speed up matching,  pcre_study()  returns  a
+        information  that  will  help speed up matching, pcre_study() returns a
-        pointer  to a pcre_extra block, in which the study_data field points to
+        pointer to a pcre_extra block, in which the study_data field points  to
         the results of the study.
         The  returned  value  from  pcre_study()  can  be  passed  directly  to
-        pcre_exec().  However,  a  pcre_extra  block also contains other fields
+        pcre_exec(). However, a pcre_extra block  also  contains  other  fields
-        that can be set by the caller before the block  is  passed;  these  are
+        that  can  be  set  by the caller before the block is passed; these are
         described below in the section on matching a pattern.
-        If  studying  the  pattern  does not produce any additional information
+        If studying the pattern does not  produce  any  additional  information
         pcre_study() returns NULL. In that circumstance, if the calling program
-        wants  to  pass  any of the other fields to pcre_exec(), it must set up
+        wants to pass any of the other fields to pcre_exec(), it  must  set  up
         its own pcre_extra block.
-        The second argument of pcre_study() contains option bits.  At  present,
+        The  second  argument of pcre_study() contains option bits. At present,
         no options are defined, and this argument should always be zero.
-        The  third argument for pcre_study() is a pointer for an error message.
+        The third argument for pcre_study() is a pointer for an error  message.
-        If studying succeeds (even if no data is  returned),  the  variable  it
+        If  studying  succeeds  (even  if no data is returned), the variable it
-        points  to  is  set  to NULL. Otherwise it is set to point to a textual
+        points to is set to NULL. Otherwise it is set to  point  to  a  textual
         error message. This is a static string that is part of the library. You
-        must  not  try  to  free it. You should test the error pointer for NULL
+        must not try to free it. You should test the  error  pointer  for  NULL
         after calling pcre_study(), to be sure that it has run successfully.
         This is a typical call to pcre_study():
-Line 1343 
 STUDYING A PATTERN
+Line 1378 
 STUDYING A PATTERN
             &error);        /* set to NULL or points to a message */
         At present, studying a pattern is useful only for non-anchored patterns
-        that  do not have a single fixed starting character. A bitmap of possi-
+        that do not have a single fixed starting character. A bitmap of  possi-
         ble starting bytes is created.
  LOCALE SUPPORT
-        PCRE handles caseless matching, and determines whether  characters  are
+        PCRE  handles  caseless matching, and determines whether characters are
-        letters,  digits, or whatever, by reference to a set of tables, indexed
+        letters, digits, or whatever, by reference to a set of tables,  indexed
-        by character value. When running in UTF-8 mode, this  applies  only  to
+        by  character  value.  When running in UTF-8 mode, this applies only to
-        characters  with  codes  less than 128. Higher-valued codes never match
+        characters with codes less than 128. Higher-valued  codes  never  match
-        escapes such as \w or \d, but can be tested with \p if  PCRE  is  built
+        escapes  such  as  \w or \d, but can be tested with \p if PCRE is built
-        with  Unicode  character property support. The use of locales with Uni-
+        with Unicode character property support. The use of locales  with  Uni-
-        code is discouraged. If you are handling characters with codes  greater
+        code  is discouraged. If you are handling characters with codes greater
-        than  128, you should either use UTF-8 and Unicode, or use locales, but
+        than 128, you should either use UTF-8 and Unicode, or use locales,  but
         not try to mix the two.
-        PCRE contains an internal set of tables that are used  when  the  final
+        PCRE  contains  an  internal set of tables that are used when the final
-        argument  of  pcre_compile()  is  NULL.  These  are sufficient for many
+        argument of pcre_compile() is  NULL.  These  are  sufficient  for  many
         applications.  Normally, the internal tables recognize only ASCII char-
         acters. However, when PCRE is built, it is possible to cause the inter-
         nal tables to be rebuilt in the default "C" locale of the local system,
         which may cause them to be different.
-        The  internal tables can always be overridden by tables supplied by the
+        The internal tables can always be overridden by tables supplied by  the
         application that calls PCRE. These may be created in a different locale
-        from  the  default.  As more and more applications change to using Uni-
+        from the default. As more and more applications change  to  using  Uni-
         code, the need for this locale support is expected to die away.
-        External tables are built by calling  the  pcre_maketables()  function,
+        External  tables  are  built by calling the pcre_maketables() function,
-        which  has no arguments, in the relevant locale. The result can then be
+        which has no arguments, in the relevant locale. The result can then  be
-        passed to pcre_compile() or pcre_exec()  as  often  as  necessary.  For
+        passed  to  pcre_compile()  or  pcre_exec()  as often as necessary. For
-        example,  to  build  and use tables that are appropriate for the French
+        example, to build and use tables that are appropriate  for  the  French
-        locale (where accented characters with  values  greater  than  128  are
+        locale  (where  accented  characters  with  values greater than 128 are
         treated as letters), the following code could be used:
           setlocale(LC_CTYPE, "fr_FR");
           tables = pcre_maketables();
           re = pcre_compile(..., tables);
-        The  locale  name "fr_FR" is used on Linux and other Unix-like systems;
+        The locale name "fr_FR" is used on Linux and other  Unix-like  systems;
         if you are using Windows, the name for the French locale is "french".
-        When pcre_maketables() runs, the tables are built  in  memory  that  is
+        When  pcre_maketables()  runs,  the  tables are built in memory that is
-        obtained  via  pcre_malloc. It is the caller's responsibility to ensure
+        obtained via pcre_malloc. It is the caller's responsibility  to  ensure
-        that the memory containing the tables remains available for as long  as
+        that  the memory containing the tables remains available for as long as
         it is needed.
         The pointer that is passed to pcre_compile() is saved with the compiled
-        pattern, and the same tables are used via this pointer by  pcre_study()
+        pattern,  and the same tables are used via this pointer by pcre_study()
         and normally also by pcre_exec(). Thus, by default, for any single pat-
         tern, compilation, studying and matching all happen in the same locale,
         but different patterns can be compiled in different locales.
-        It  is  possible to pass a table pointer or NULL (indicating the use of
+        It is possible to pass a table pointer or NULL (indicating the  use  of
-        the internal tables) to pcre_exec(). Although  not  intended  for  this
+        the  internal  tables)  to  pcre_exec(). Although not intended for this
-        purpose,  this facility could be used to match a pattern in a different
+        purpose, this facility could be used to match a pattern in a  different
         locale from the one in which it was compiled. Passing table pointers at
         run time is discussed below in the section on matching a pattern.
-Line 1408 
 INFORMATION ABOUT A PATTERN
+Line 1443 
 INFORMATION ABOUT A PATTERN
         int pcre_fullinfo(const pcre *code, const pcre_extra *extra,
              int what, void *where);
-        The  pcre_fullinfo() function returns information about a compiled pat-
+        The pcre_fullinfo() function returns information about a compiled  pat-
         tern. It replaces the obsolete pcre_info() function, which is neverthe-
         less retained for backwards compability (and is documented below).
-        The  first  argument  for  pcre_fullinfo() is a pointer to the compiled
+        The first argument for pcre_fullinfo() is a  pointer  to  the  compiled
-        pattern. The second argument is the result of pcre_study(), or NULL  if
+        pattern.  The second argument is the result of pcre_study(), or NULL if
-        the  pattern  was not studied. The third argument specifies which piece
+        the pattern was not studied. The third argument specifies  which  piece
-        of information is required, and the fourth argument is a pointer  to  a
+        of  information  is required, and the fourth argument is a pointer to a
-        variable  to  receive  the  data. The yield of the function is zero for
+        variable to receive the data. The yield of the  function  is  zero  for
         success, or one of the following negative numbers:
           PCRE_ERROR_NULL       the argument code was NULL
-Line 1424 
 INFORMATION ABOUT A PATTERN
+Line 1459 
 INFORMATION ABOUT A PATTERN
           PCRE_ERROR_BADMAGIC   the "magic number" was not found
           PCRE_ERROR_BADOPTION  the value of what was invalid
-        The "magic number" is placed at the start of each compiled  pattern  as
+        The  "magic  number" is placed at the start of each compiled pattern as
-        an  simple check against passing an arbitrary memory pointer. Here is a
+        an simple check against passing an arbitrary memory pointer. Here is  a
-        typical call of pcre_fullinfo(), to obtain the length of  the  compiled
+        typical  call  of pcre_fullinfo(), to obtain the length of the compiled
         pattern:
           int rc;
-Line 1437 
 INFORMATION ABOUT A PATTERN
+Line 1472 
 INFORMATION ABOUT A PATTERN
             PCRE_INFO_SIZE,   /* what is required */
             &length);         /* where to put the data */
-        The  possible  values for the third argument are defined in pcre.h, and
+        The possible values for the third argument are defined in  pcre.h,  and
         are as follows:
           PCRE_INFO_BACKREFMAX
-        Return the number of the highest back reference  in  the  pattern.  The
+        Return  the  number  of  the highest back reference in the pattern. The
-        fourth  argument  should  point to an int variable. Zero is returned if
+        fourth argument should point to an int variable. Zero  is  returned  if
         there are no back references.
           PCRE_INFO_CAPTURECOUNT
-        Return the number of capturing subpatterns in the pattern.  The  fourth
+        Return  the  number of capturing subpatterns in the pattern. The fourth
         argument should point to an int variable.
           PCRE_INFO_DEFAULT_TABLES
-        Return  a pointer to the internal default character tables within PCRE.
+        Return a pointer to the internal default character tables within  PCRE.
-        The fourth argument should point to an unsigned char *  variable.  This
+        The  fourth  argument should point to an unsigned char * variable. This
         information call is provided for internal use by the pcre_study() func-
-        tion. External callers can cause PCRE to use  its  internal  tables  by
+        tion.  External  callers  can  cause PCRE to use its internal tables by
         passing a NULL table pointer.
           PCRE_INFO_FIRSTBYTE
-        Return  information  about  the first byte of any matched string, for a
+        Return information about the first byte of any matched  string,  for  a
-        non-anchored pattern. The fourth argument should point to an int  vari-
+        non-anchored  pattern. The fourth argument should point to an int vari-
-        able.  (This option used to be called PCRE_INFO_FIRSTCHAR; the old name
+        able. (This option used to be called PCRE_INFO_FIRSTCHAR; the old  name
         is still recognized for backwards compatibility.)
-        If there is a fixed first byte, for example, from  a  pattern  such  as
+        If  there  is  a  fixed first byte, for example, from a pattern such as
         (cat|cow|coyote), its value is returned. Otherwise, if either
-        (a)  the pattern was compiled with the PCRE_MULTILINE option, and every
+        (a) the pattern was compiled with the PCRE_MULTILINE option, and  every
         branch starts with "^", or
         (b) every branch of the pattern starts with ".*" and PCRE_DOTALL is not
         set (if it were set, the pattern would be anchored),
-        -1  is  returned, indicating that the pattern matches only at the start
+        -1 is returned, indicating that the pattern matches only at  the  start
-        of a subject string or after any newline within the  string.  Otherwise
+        of  a  subject string or after any newline within the string. Otherwise
         -2 is returned. For anchored patterns, -2 is returned.
           PCRE_INFO_FIRSTTABLE
-        If  the pattern was studied, and this resulted in the construction of a
+        If the pattern was studied, and this resulted in the construction of  a
 -bit table indicating a fixed set of bytes for the first byte in any
-        matching  string, a pointer to the table is returned. Otherwise NULL is
+        matching string, a pointer to the table is returned. Otherwise NULL  is
-        returned. The fourth argument should point to an unsigned char *  vari-
+        returned.  The fourth argument should point to an unsigned char * vari-
         able.
           PCRE_INFO_JCHANGED
-        Return  1  if the (?J) option setting is used in the pattern, otherwise
+        Return 1 if the (?J) option setting is used in the  pattern,  otherwise
 . The fourth argument should point to an int variable. The (?J) inter-
         nal option setting changes the local PCRE_DUPNAMES option.
           PCRE_INFO_LASTLITERAL
-        Return  the  value of the rightmost literal byte that must exist in any
+        Return the value of the rightmost literal byte that must exist  in  any
-        matched string, other than at its  start,  if  such  a  byte  has  been
+        matched  string,  other  than  at  its  start,  if such a byte has been
         recorded. The fourth argument should point to an int variable. If there
-        is no such byte, -1 is returned. For anchored patterns, a last  literal
+        is  no such byte, -1 is returned. For anchored patterns, a last literal
-        byte  is  recorded only if it follows something of variable length. For
+        byte is recorded only if it follows something of variable  length.  For
         example, for the pattern /^a\d+z\d+/ the returned value is "z", but for
         /^a\dz\d/ the returned value is -1.
-Line 1507 
 INFORMATION ABOUT A PATTERN
+Line 1542 
 INFORMATION ABOUT A PATTERN
           PCRE_INFO_NAMEENTRYSIZE
           PCRE_INFO_NAMETABLE
-        PCRE  supports the use of named as well as numbered capturing parenthe-
+        PCRE supports the use of named as well as numbered capturing  parenthe-
-        ses. The names are just an additional way of identifying the  parenthe-
+        ses.  The names are just an additional way of identifying the parenthe-
         ses, which still acquire numbers. Several convenience functions such as
-        pcre_get_named_substring() are provided for  extracting  captured  sub-
+        pcre_get_named_substring()  are  provided  for extracting captured sub-
-        strings  by  name. It is also possible to extract the data directly, by
+        strings by name. It is also possible to extract the data  directly,  by
-        first converting the name to a number in order to  access  the  correct
+        first  converting  the  name to a number in order to access the correct
         pointers in the output vector (described with pcre_exec() below). To do
-        the conversion, you need  to  use  the  name-to-number  map,  which  is
+        the  conversion,  you  need  to  use  the  name-to-number map, which is
         described by these three values.
         The map consists of a number of fixed-size entries. PCRE_INFO_NAMECOUNT
         gives the number of entries, and PCRE_INFO_NAMEENTRYSIZE gives the size
-        of  each  entry;  both  of  these  return  an int value. The entry size
+        of each entry; both of these  return  an  int  value.  The  entry  size
-        depends on the length of the longest name. PCRE_INFO_NAMETABLE  returns
+        depends  on the length of the longest name. PCRE_INFO_NAMETABLE returns
-        a  pointer  to  the  first  entry of the table (a pointer to char). The
+        a pointer to the first entry of the table  (a  pointer  to  char).  The
         first two bytes of each entry are the number of the capturing parenthe-
-        sis,  most  significant byte first. The rest of the entry is the corre-
+        sis, most significant byte first. The rest of the entry is  the  corre-
-        sponding name, zero terminated. The names are  in  alphabetical  order.
+        sponding  name,  zero  terminated. The names are in alphabetical order.
         When PCRE_DUPNAMES is set, duplicate names are in order of their paren-
-        theses numbers. For example, consider  the  following  pattern  (assume
+        theses  numbers.  For  example,  consider the following pattern (assume
-        PCRE_EXTENDED  is  set,  so  white  space  -  including  newlines  - is
+        PCRE_EXTENDED is  set,  so  white  space  -  including  newlines  -  is
         ignored):
           (?<date> (?<year>(\d\d)?\d\d) -
           (?<month>\d\d) - (?<day>\d\d) )
-        There are four named subpatterns, so the table has  four  entries,  and
+        There  are  four  named subpatterns, so the table has four entries, and
-        each  entry  in the table is eight bytes long. The table is as follows,
+        each entry in the table is eight bytes long. The table is  as  follows,
         with non-printing bytes shows in hexadecimal, and undefined bytes shown
         as ??:
-Line 1543 
 INFORMATION ABOUT A PATTERN
+Line 1578 
 INFORMATION ABOUT A PATTERN
 04 m  o  n  t  h  00
 02 y  e  a  r  00 ??
-        When  writing  code  to  extract  data from named subpatterns using the
+        When writing code to extract data  from  named  subpatterns  using  the
-        name-to-number map, remember that the length of the entries  is  likely
+        name-to-number  map,  remember that the length of the entries is likely
         to be different for each compiled pattern.
           PCRE_INFO_OKPARTIAL
-        Return  1 if the pattern can be used for partial matching, otherwise 0.
+        Return 1 if the pattern can be used for partial matching, otherwise  0.
-        The fourth argument should point to an int  variable.  The  pcrepartial
+        The  fourth  argument  should point to an int variable. The pcrepartial
-        documentation  lists  the restrictions that apply to patterns when par-
+        documentation lists the restrictions that apply to patterns  when  par-
         tial matching is used.
           PCRE_INFO_OPTIONS
-        Return a copy of the options with which the pattern was  compiled.  The
+        Return  a  copy of the options with which the pattern was compiled. The
-        fourth  argument  should  point to an unsigned long int variable. These
+        fourth argument should point to an unsigned long  int  variable.  These
         option bits are those specified in the call to pcre_compile(), modified
-        by any top-level option settings within the pattern itself.
+        by any top-level option settings at the start of the pattern itself. In
+        other  words,  they are the options that will be in force when matching
+        starts. For example, if the pattern /(?im)abc(?-i)d/ is  compiled  with
+        the  PCRE_EXTENDED option, the result is PCRE_CASELESS, PCRE_MULTILINE,
+        and PCRE_EXTENDED.
-        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
         alternatives begin with one of the following:
           ^     unless PCRE_MULTILINE is set
-Line 1575 
 INFORMATION ABOUT A PATTERN
+Line 1614 
 INFORMATION ABOUT A PATTERN
           PCRE_INFO_SIZE
-        Return  the  size  of the compiled pattern, that is, the value that was
+        Return the size of the compiled pattern, that is, the  value  that  was
         passed as the argument to pcre_malloc() when PCRE was getting memory in
         which to place the compiled data. The fourth argument should point to a
         size_t variable.
-Line 1583 
 INFORMATION ABOUT A PATTERN
+Line 1622 
 INFORMATION ABOUT A PATTERN
           PCRE_INFO_STUDYSIZE
         Return the size of the data block pointed to by the study_data field in
-        a  pcre_extra  block.  That  is,  it  is  the  value that was passed to
+        a pcre_extra block. That is,  it  is  the  value  that  was  passed  to
         pcre_malloc() when PCRE was getting memory into which to place the data
-        created  by  pcre_study(). The fourth argument should point to a size_t
+        created by pcre_study(). The fourth argument should point to  a  size_t
         variable.
-Line 1593 
 OBSOLETE INFO FUNCTION
+Line 1632 
 OBSOLETE INFO FUNCTION
         int pcre_info(const pcre *code, int *optptr, int *firstcharptr);
-        The pcre_info() function is now obsolete because its interface  is  too
+        The  pcre_info()  function is now obsolete because its interface is too
-        restrictive  to return all the available data about a compiled pattern.
+        restrictive to return all the available data about a compiled  pattern.
-        New  programs  should  use  pcre_fullinfo()  instead.  The   yield   of
+        New   programs   should  use  pcre_fullinfo()  instead.  The  yield  of
-        pcre_info()  is the number of capturing subpatterns, or one of the fol-
+        pcre_info() is the number of capturing subpatterns, or one of the  fol-
         lowing negative numbers:
           PCRE_ERROR_NULL       the argument code was NULL
           PCRE_ERROR_BADMAGIC   the "magic number" was not found
-        If the optptr argument is not NULL, a copy of the  options  with  which
+        If  the  optptr  argument is not NULL, a copy of the options with which
-        the  pattern  was  compiled  is placed in the integer it points to (see
+        the pattern was compiled is placed in the integer  it  points  to  (see
         PCRE_INFO_OPTIONS above).
-        If the pattern is not anchored and the  firstcharptr  argument  is  not
+        If  the  pattern  is  not anchored and the firstcharptr argument is not
-        NULL,  it is used to pass back information about the first character of
+        NULL, it is used to pass back information about the first character  of
         any matched string (see PCRE_INFO_FIRSTBYTE above).
-Line 1615 
 REFERENCE COUNTS
+Line 1654 
 REFERENCE COUNTS
         int pcre_refcount(pcre *code, int adjust);
-        The pcre_refcount() function is used to maintain a reference  count  in
+        The  pcre_refcount()  function is used to maintain a reference count in
         the data block that contains a compiled pattern. It is provided for the
-        benefit of applications that  operate  in  an  object-oriented  manner,
+        benefit  of  applications  that  operate  in an object-oriented manner,
         where different parts of the application may be using the same compiled
         pattern, but you want to free the block when they are all done.
         When a pattern is compiled, the reference count field is initialized to
-        zero.   It is changed only by calling this function, whose action is to
+        zero.  It is changed only by calling this function, whose action is  to
-        add the adjust value (which may be positive or  negative)  to  it.  The
+        add  the  adjust  value  (which may be positive or negative) to it. The
         yield of the function is the new value. However, the value of the count
-        is constrained to lie between 0 and 65535, inclusive. If the new  value
+        is  constrained to lie between 0 and 65535, inclusive. If the new value
         is outside these limits, it is forced to the appropriate limit value.
-        Except  when it is zero, the reference count is not correctly preserved
+        Except when it is zero, the reference count is not correctly  preserved
-        if a pattern is compiled on one host and then  transferred  to  a  host
+        if  a  pattern  is  compiled on one host and then transferred to a host
         whose byte-order is different. (This seems a highly unlikely scenario.)
-Line 1639 
 MATCHING A PATTERN: THE TRADITIONAL FUNC
+Line 1678 
 MATCHING A PATTERN: THE TRADITIONAL FUNC
              const char *subject, int length, int startoffset,
              int options, int *ovector, int ovecsize);
-        The function pcre_exec() is called to match a subject string against  a
+        The  function pcre_exec() is called to match a subject string against a
-        compiled  pattern, which is passed in the code argument. If the pattern
+        compiled pattern, which is passed in the code argument. If the  pattern
         has been studied, the result of the study should be passed in the extra
-        argument.  This  function is the main matching facility of the library,
+        argument. This function is the main matching facility of  the  library,
         and it operates in a Perl-like manner. For specialist use there is also
-        an  alternative matching function, which is described below in the sec-
+        an alternative matching function, which is described below in the  sec-
         tion about the pcre_dfa_exec() function.
-        In most applications, the pattern will have been compiled (and  option-
+        In  most applications, the pattern will have been compiled (and option-
-        ally  studied)  in the same process that calls pcre_exec(). However, it
+        ally studied) in the same process that calls pcre_exec().  However,  it
         is possible to save compiled patterns and study data, and then use them
-        later  in  different processes, possibly even on different hosts. For a
+        later in different processes, possibly even on different hosts.  For  a
         discussion about this, see the pcreprecompile documentation.
         Here is an example of a simple call to pcre_exec():
-Line 1669 
 MATCHING A PATTERN: THE TRADITIONAL FUNC
+Line 1708 
 MATCHING A PATTERN: THE TRADITIONAL FUNC
     Extra data for pcre_exec()
-        If the extra argument is not NULL, it must point to a  pcre_extra  data
+        If  the  extra argument is not NULL, it must point to a pcre_extra data
-        block.  The pcre_study() function returns such a block (when it doesn't
+        block. The pcre_study() function returns such a block (when it  doesn't
-        return NULL), but you can also create one for yourself, and pass  addi-
+        return  NULL), but you can also create one for yourself, and pass addi-
-        tional  information  in it. The pcre_extra block contains the following
+        tional information in it. The pcre_extra block contains  the  following
         fields (not necessarily in this order):
           unsigned long int flags;
-Line 1682 
 MATCHING A PATTERN: THE TRADITIONAL FUNC
+Line 1721 
 MATCHING A PATTERN: THE TRADITIONAL FUNC
           void *callout_data;
           const unsigned char *tables;
-        The flags field is a bitmap that specifies which of  the  other  fields
+        The  flags  field  is a bitmap that specifies which of the other fields
         are set. The flag bits are:
           PCRE_EXTRA_STUDY_DATA
-Line 1691 
 MATCHING A PATTERN: THE TRADITIONAL FUNC
+Line 1730 
 MATCHING A PATTERN: THE TRADITIONAL FUNC
           PCRE_EXTRA_CALLOUT_DATA
           PCRE_EXTRA_TABLES
-        Other  flag  bits should be set to zero. The study_data field is set in
+        Other flag bits should be set to zero. The study_data field is  set  in
-        the pcre_extra block that is returned by  pcre_study(),  together  with
+        the  pcre_extra  block  that is returned by pcre_study(), together with
         the appropriate flag bit. You should not set this yourself, but you may
-        add to the block by setting the other fields  and  their  corresponding
+        add  to  the  block by setting the other fields and their corresponding
         flag bits.
         The match_limit field provides a means of preventing PCRE from using up
-        a vast amount of resources when running patterns that are not going  to
+        a  vast amount of resources when running patterns that are not going to
-        match,  but  which  have  a very large number of possibilities in their
+        match, but which have a very large number  of  possibilities  in  their
-        search trees. The classic  example  is  the  use  of  nested  unlimited
+        search  trees.  The  classic  example  is  the  use of nested unlimited
         repeats.
-        Internally,  PCRE uses a function called match() which it calls repeat-
+        Internally, PCRE uses a function called match() which it calls  repeat-
-        edly (sometimes recursively). The limit set by match_limit  is  imposed
+        edly  (sometimes  recursively). The limit set by match_limit is imposed
-        on  the  number  of times this function is called during a match, which
+        on the number of times this function is called during  a  match,  which
-        has the effect of limiting the amount of  backtracking  that  can  take
+        has  the  effect  of  limiting the amount of backtracking that can take
         place. For patterns that are not anchored, the count restarts from zero
         for each position in the subject string.
-        The default value for the limit can be set  when  PCRE  is  built;  the
+        The  default  value  for  the  limit can be set when PCRE is built; the
-        default  default  is 10 million, which handles all but the most extreme
+        default default is 10 million, which handles all but the  most  extreme
-        cases. You can override the default  by  suppling  pcre_exec()  with  a
+        cases.  You  can  override  the  default by suppling pcre_exec() with a
-        pcre_extra     block    in    which    match_limit    is    set,    and
+        pcre_extra    block    in    which    match_limit    is    set,     and
-        PCRE_EXTRA_MATCH_LIMIT is set in the  flags  field.  If  the  limit  is
+        PCRE_EXTRA_MATCH_LIMIT  is  set  in  the  flags  field. If the limit is
         exceeded, pcre_exec() returns PCRE_ERROR_MATCHLIMIT.
-        The  match_limit_recursion field is similar to match_limit, but instead
+        The match_limit_recursion field is similar to match_limit, but  instead
         of limiting the total number of times that match() is called, it limits
-        the  depth  of  recursion. The recursion depth is a smaller number than
+        the depth of recursion. The recursion depth is a  smaller  number  than
-        the total number of calls, because not all calls to match() are  recur-
+        the  total number of calls, because not all calls to match() are recur-
         sive.  This limit is of use only if it is set smaller than match_limit.
-        Limiting the recursion depth limits the amount of  stack  that  can  be
+        Limiting  the  recursion  depth  limits the amount of stack that can be
         used, or, when PCRE has been compiled to use memory on the heap instead
         of the stack, the amount of heap memory that can be used.
-        The default value for match_limit_recursion can be  set  when  PCRE  is
+        The  default  value  for  match_limit_recursion can be set when PCRE is
-        built;  the  default  default  is  the  same  value  as the default for
+        built; the default default  is  the  same  value  as  the  default  for
-        match_limit. You can override the default by suppling pcre_exec()  with
+        match_limit.  You can override the default by suppling pcre_exec() with
-        a   pcre_extra   block  in  which  match_limit_recursion  is  set,  and
+        a  pcre_extra  block  in  which  match_limit_recursion  is   set,   and
-        PCRE_EXTRA_MATCH_LIMIT_RECURSION is set in  the  flags  field.  If  the
+        PCRE_EXTRA_MATCH_LIMIT_RECURSION  is  set  in  the  flags field. If the
         limit is exceeded, pcre_exec() returns PCRE_ERROR_RECURSIONLIMIT.
-        The  pcre_callout  field is used in conjunction with the "callout" fea-
+        The pcre_callout field is used in conjunction with the  "callout"  fea-
         ture, which is described in the pcrecallout documentation.
-        The tables field  is  used  to  pass  a  character  tables  pointer  to
+        The  tables  field  is  used  to  pass  a  character  tables pointer to
-        pcre_exec();  this overrides the value that is stored with the compiled
+        pcre_exec(); this overrides the value that is stored with the  compiled
-        pattern. A non-NULL value is stored with the compiled pattern  only  if
+        pattern.  A  non-NULL value is stored with the compiled pattern only if
-        custom  tables  were  supplied to pcre_compile() via its tableptr argu-
+        custom tables were supplied to pcre_compile() via  its  tableptr  argu-
         ment.  If NULL is passed to pcre_exec() using this mechanism, it forces
-        PCRE's  internal  tables  to be used. This facility is helpful when re-
+        PCRE's internal tables to be used. This facility is  helpful  when  re-
-        using patterns that have been saved after compiling  with  an  external
+        using  patterns  that  have been saved after compiling with an external
-        set  of  tables,  because  the  external tables might be at a different
+        set of tables, because the external tables  might  be  at  a  different
-        address when pcre_exec() is called. See the  pcreprecompile  documenta-
+        address  when  pcre_exec() is called. See the pcreprecompile documenta-
         tion for a discussion of saving compiled patterns for later use.
     Option bits for pcre_exec()
-        The  unused  bits of the options argument for pcre_exec() must be zero.
+        The unused bits of the options argument for pcre_exec() must  be  zero.
-        The only bits that may  be  set  are  PCRE_ANCHORED,  PCRE_NEWLINE_xxx,
+        The  only  bits  that  may  be set are PCRE_ANCHORED, PCRE_NEWLINE_xxx,
         PCRE_NOTBOL,   PCRE_NOTEOL,   PCRE_NOTEMPTY,   PCRE_NO_UTF8_CHECK   and
         PCRE_PARTIAL.
           PCRE_ANCHORED
-        The PCRE_ANCHORED option limits pcre_exec() to matching  at  the  first
+        The  PCRE_ANCHORED  option  limits pcre_exec() to matching at the first
-        matching  position.  If  a  pattern was compiled with PCRE_ANCHORED, or
+        matching position. If a pattern was  compiled  with  PCRE_ANCHORED,  or
-        turned out to be anchored by virtue of its contents, it cannot be  made
+        turned  out to be anchored by virtue of its contents, it cannot be made
         unachored at matching time.
           PCRE_NEWLINE_CR
-Line 1768 
 MATCHING A PATTERN: THE TRADITIONAL FUNC
+Line 1807 
 MATCHING A PATTERN: THE TRADITIONAL FUNC
           PCRE_NEWLINE_ANYCRLF
           PCRE_NEWLINE_ANY
-        These  options  override  the  newline  definition  that  was chosen or
+        These options override  the  newline  definition  that  was  chosen  or
-        defaulted when the pattern was compiled. For details, see the  descrip-
+        defaulted  when the pattern was compiled. For details, see the descrip-
-        tion  of  pcre_compile()  above.  During  matching,  the newline choice
+        tion of pcre_compile()  above.  During  matching,  the  newline  choice
-        affects the behaviour of the dot, circumflex,  and  dollar  metacharac-
+        affects  the  behaviour  of the dot, circumflex, and dollar metacharac-
-        ters.  It may also alter the way the match position is advanced after a
+        ters. It may also alter the way the match position is advanced after  a
         match  failure  for  an  unanchored  pattern.  When  PCRE_NEWLINE_CRLF,
-        PCRE_NEWLINE_ANYCRLF,  or  PCRE_NEWLINE_ANY is set, and a match attempt
+        PCRE_NEWLINE_ANYCRLF, or PCRE_NEWLINE_ANY is set, and a  match  attempt
-        fails when the current position is at a CRLF sequence, the match  posi-
+        fails  when the current position is at a CRLF sequence, the match posi-
-        tion  is  advanced by two characters instead of one, in other words, to
+        tion is advanced by two characters instead of one, in other  words,  to
         after the CRLF.
           PCRE_NOTBOL
         This option specifies that first character of the subject string is not
-        the  beginning  of  a  line, so the circumflex metacharacter should not
+        the beginning of a line, so the  circumflex  metacharacter  should  not
-        match before it. Setting this without PCRE_MULTILINE (at compile  time)
+        match  before it. Setting this without PCRE_MULTILINE (at compile time)
-        causes  circumflex  never to match. This option affects only the behav-
+        causes circumflex never to match. This option affects only  the  behav-
         iour of the circumflex metacharacter. It does not affect \A.
           PCRE_NOTEOL
         This option specifies that the end of the subject string is not the end
-        of  a line, so the dollar metacharacter should not match it nor (except
+        of a line, so the dollar metacharacter should not match it nor  (except
-        in multiline mode) a newline immediately before it. Setting this  with-
+        in  multiline mode) a newline immediately before it. Setting this with-
         out PCRE_MULTILINE (at compile time) causes dollar never to match. This
-        option affects only the behaviour of the dollar metacharacter. It  does
+        option  affects only the behaviour of the dollar metacharacter. It does
         not affect \Z or \z.
           PCRE_NOTEMPTY
         An empty string is not considered to be a valid match if this option is
-        set. If there are alternatives in the pattern, they are tried.  If  all
+        set.  If  there are alternatives in the pattern, they are tried. If all
-        the  alternatives  match  the empty string, the entire match fails. For
+        the alternatives match the empty string, the entire  match  fails.  For
         example, if the pattern
           a?b?
-        is applied to a string not beginning with "a" or "b",  it  matches  the
+        is  applied  to  a string not beginning with "a" or "b", it matches the
-        empty  string at the start of the subject. With PCRE_NOTEMPTY set, this
+        empty string at the start of the subject. With PCRE_NOTEMPTY set,  this
         match is not valid, so PCRE searches further into the string for occur-
         rences of "a" or "b".
         Perl has no direct equivalent of PCRE_NOTEMPTY, but it does make a spe-
-        cial case of a pattern match of the empty  string  within  its  split()
+        cial  case  of  a  pattern match of the empty string within its split()
-        function,  and  when  using  the /g modifier. It is possible to emulate
+        function, and when using the /g modifier. It  is  possible  to  emulate
         Perl's behaviour after matching a null string by first trying the match
         again at the same offset with PCRE_NOTEMPTY and PCRE_ANCHORED, and then
-        if that fails by advancing the starting offset (see below)  and  trying
+        if  that  fails by advancing the starting offset (see below) and trying
         an ordinary match again. There is some code that demonstrates how to do
         this in the pcredemo.c sample program.
           PCRE_NO_UTF8_CHECK
         When PCRE_UTF8 is set at compile time, the validity of the subject as a
-        UTF-8  string is automatically checked when pcre_exec() is subsequently
+        UTF-8 string is automatically checked when pcre_exec() is  subsequently
-        called.  The value of startoffset is also checked  to  ensure  that  it
+        called.   The  value  of  startoffset is also checked to ensure that it
-        points  to the start of a UTF-8 character. If an invalid UTF-8 sequence
+        points to the start of a UTF-8 character. There is a  discussion  about
-        of bytes is found, pcre_exec() returns the error PCRE_ERROR_BADUTF8. If
+        the  validity  of  UTF-8 strings in the section on UTF-8 support in the
-        startoffset  contains  an  invalid  value, PCRE_ERROR_BADUTF8_OFFSET is
+        main pcre page. If  an  invalid  UTF-8  sequence  of  bytes  is  found,
-        returned.
+        pcre_exec()  returns  the error PCRE_ERROR_BADUTF8. If startoffset con-
+        tains an invalid value, PCRE_ERROR_BADUTF8_OFFSET is returned.
         If you already know that your subject is valid, and you  want  to  skip
         these    checks    for   performance   reasons,   you   can   set   the
-Line 2050 
 MATCHING A PATTERN: THE TRADITIONAL FUNC
+Line 2090 
 MATCHING A PATTERN: THE TRADITIONAL FUNC
         field  in  a  pcre_extra  structure (or defaulted) was reached. See the
         description above.
-          PCRE_ERROR_NULLWSLIMIT    (-22)
-        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.
           PCRE_ERROR_BADNEWLINE     (-23)
         An invalid combination of PCRE_NEWLINE_xxx options was given.
-        Error numbers -16 to -20 are not used by pcre_exec().
+        Error numbers -16 to -20 and -22 are not used by pcre_exec().
  EXTRACTING CAPTURED SUBSTRINGS BY NUMBER
-Line 2210 
 DUPLICATE SUBPATTERN NAMES
+Line 2242 
 DUPLICATE SUBPATTERN NAMES
         subpatterns  are  not  required  to  be unique. Normally, patterns with
         duplicate names are such that in any one match, only one of  the  named
         subpatterns  participates. An example is shown in the pcrepattern docu-
-        mentation. When duplicates are present, pcre_copy_named_substring() and
+        mentation.
+        When   duplicates   are   present,   pcre_copy_named_substring()    and
         pcre_get_named_substring()  return the first substring corresponding to
-        the given name that is set.  If  none  are  set,  an  empty  string  is
+        the given name that is set. If  none  are  set,  PCRE_ERROR_NOSUBSTRING
-        returned.  The pcre_get_stringnumber() function returns one of the num-
+        (-7)  is  returned;  no  data  is returned. The pcre_get_stringnumber()
-        bers that are associated with the name, but it is not defined which  it
+        function returns one of the numbers that are associated with the  name,
-        is.
+        but it is not defined which it is.
         If  you want to get full details of all captured substrings for a given
         name, you must use  the  pcre_get_stringtable_entries()  function.  The
-Line 2417 
 AUTHOR
+Line 2451 
 AUTHOR
  REVISION
-        Last updated: 13 June 2007
+        Last updated: 09 August 2007
         Copyright (c) 1997-2007 University of Cambridge.
  ------------------------------------------------------------------------------
-Line 2670 
 DIFFERENCES BETWEEN PCRE AND PERL
+Line 2704 
 DIFFERENCES BETWEEN PCRE AND PERL
         matching  "aba"  against  the  pattern  /^(a(b)?)+$/  in Perl leaves $2
         unset, but in PCRE it is set to "b".
-. PCRE provides some extensions to the Perl regular expression facil-
+.  PCRE  does  support  Perl  5.10's  backtracking  verbs  (*ACCEPT),
+        (*FAIL),  (*F),  (*COMMIT), (*PRUNE), (*SKIP), and (*THEN), but only in
+        the forms without an  argument.  PCRE  does  not  support  (*MARK).  If
+        (*ACCEPT)  is within capturing parentheses, PCRE does not set that cap-
+        ture group; this is different to Perl.
+. PCRE provides some extensions to the Perl regular expression facil-
         ities.   Perl  5.10  will  include new features that are not in earlier
         versions, some of which (such as named parentheses) have been  in  PCRE
         for some time. This list is with respect to Perl 5.10:
-Line 2716 
 AUTHOR
+Line 2756 
 AUTHOR
  REVISION
-        Last updated: 13 June 2007
+        Last updated: 08 August 2007
         Copyright (c) 1997-2007 University of Cambridge.
  ------------------------------------------------------------------------------
-Line 2730 
 NAME
+Line 2770 
 NAME
  PCRE REGULAR EXPRESSION DETAILS
-        The  syntax  and semantics of the regular expressions supported by PCRE
+        The  syntax and semantics of the regular expressions that are supported
-        are described below. Regular expressions are also described in the Perl
+        by PCRE are described in detail below. There is a quick-reference  syn-
-        documentation  and  in  a  number  of books, some of which have copious
+        tax  summary  in  the  pcresyntax  page. Perl's regular expressions are
-        examples.  Jeffrey Friedl's "Mastering Regular Expressions",  published
+        described in its own documentation, and regular expressions in  general
-        by  O'Reilly, covers regular expressions in great detail. This descrip-
+        are  covered in a number of books, some of which have copious examples.
-        tion of PCRE's regular expressions is intended as reference material.
+        Jeffrey  Friedl's  "Mastering  Regular   Expressions",   published   by
+        O'Reilly,  covers regular expressions in great detail. This description
+        of PCRE's regular expressions is intended as reference material.
         The original operation of PCRE was on strings of  one-byte  characters.
         However,  there is now also support for UTF-8 character strings. To use
-Line 2877 
 BACKSLASH
+Line 2919 
 BACKSLASH
         After  \x, from zero to two hexadecimal digits are read (letters can be
         in upper or lower case). Any number of hexadecimal  digits  may  appear
         between  \x{  and  },  but the value of the character code must be less
-        than 256 in non-UTF-8 mode, and less than 2**31 in UTF-8 mode (that is,
+        than 256 in non-UTF-8 mode, and less than 2**31 in UTF-8 mode. That is,
-        the  maximum  hexadecimal  value is 7FFFFFFF). If characters other than
+        the  maximum value in hexadecimal is 7FFFFFFF. Note that this is bigger
-        hexadecimal digits appear between \x{ and }, or if there is  no  termi-
+        than the largest Unicode code point, which is 10FFFF.
-        nating  }, this form of escape is not recognized.  Instead, the initial
-        \x will be interpreted as a basic hexadecimal escape, with no following
+        If characters other than hexadecimal digits appear between \x{  and  },
-        digits, giving a character whose value is zero.
+        or if there is no terminating }, this form of escape is not recognized.
+        Instead, the initial \x will be  interpreted  as  a  basic  hexadecimal
+        escape,  with  no  following  digits, giving a character whose value is
+        zero.
         Characters whose value is less than 256 can be defined by either of the
-        two syntaxes for \x. There is no difference in the way  they  are  han-
+        two  syntaxes  for  \x. There is no difference in the way they are han-
         dled. For example, \xdc is exactly the same as \x{dc}.
-        After  \0  up  to two further octal digits are read. If there are fewer
+        After \0 up to two further octal digits are read. If  there  are  fewer
-        than two digits, just  those  that  are  present  are  used.  Thus  the
+        than  two  digits,  just  those  that  are  present  are used. Thus the
         sequence \0\x\07 specifies two binary zeros followed by a BEL character
-        (code value 7). Make sure you supply two digits after the initial  zero
+        (code  value 7). Make sure you supply two digits after the initial zero
         if the pattern character that follows is itself an octal digit.
         The handling of a backslash followed by a digit other than 0 is compli-
         cated.  Outside a character class, PCRE reads it and any following dig-
-        its  as  a  decimal  number. If the number is less than 10, or if there
+        its as a decimal number. If the number is less than  10,  or  if  there
         have been at least that many previous capturing left parentheses in the
-        expression,  the  entire  sequence  is  taken  as  a  back reference. A
+        expression, the entire  sequence  is  taken  as  a  back  reference.  A
-        description of how this works is given later, following the  discussion
+        description  of how this works is given later, following the discussion
         of parenthesized subpatterns.
-        Inside  a  character  class, or if the decimal number is greater than 9
+        Inside a character class, or if the decimal number is  greater  than  9
-        and there have not been that many capturing subpatterns, PCRE  re-reads
+        and  there have not been that many capturing subpatterns, PCRE re-reads
         up to three octal digits following the backslash, and uses them to gen-
-        erate a data character. Any subsequent digits stand for themselves.  In
+        erate  a data character. Any subsequent digits stand for themselves. In
-        non-UTF-8  mode,  the  value  of a character specified in octal must be
+        non-UTF-8 mode, the value of a character specified  in  octal  must  be
-        less than \400. In UTF-8 mode, values up to  \777  are  permitted.  For
+        less  than  \400.  In  UTF-8 mode, values up to \777 are permitted. For
         example:
           \040   is another way of writing a space
-Line 2925 
 BACKSLASH
+Line 2970 
 BACKSLASH
           \81    is either a back reference, or a binary zero
                     followed by the two characters "8" and "1"
-        Note  that  octal  values of 100 or greater must not be introduced by a
+        Note that octal values of 100 or greater must not be  introduced  by  a
         leading zero, because no more than three octal digits are ever read.
         All the sequences that define a single character value can be used both
-        inside  and  outside character classes. In addition, inside a character
+        inside and outside character classes. In addition, inside  a  character
-        class, the sequence \b is interpreted as the backspace  character  (hex
+        class,  the  sequence \b is interpreted as the backspace character (hex
-),  and the sequences \R and \X are interpreted as the characters "R"
+), and the sequences \R and \X are interpreted as the characters  "R"
-        and "X", respectively. Outside a character class, these sequences  have
+        and  "X", respectively. Outside a character class, these sequences have
         different meanings (see below).
     Absolute and relative back references
-        The  sequence  \g followed by a positive or negative number, optionally
+        The sequence \g followed by an unsigned or a negative  number,  option-
-        enclosed in braces, is an absolute or relative back reference. A  named
+        ally  enclosed  in braces, is an absolute or relative back reference. A
-        back  reference can be coded as \g{name}. Back references are discussed
+        named back reference can be coded as \g{name}. Back references are dis-
-        later, following the discussion of parenthesized subpatterns.
+        cussed later, following the discussion of parenthesized subpatterns.
     Generic character types
-Line 2959 
 BACKSLASH
+Line 3004 
 BACKSLASH
           \W     any "non-word" character
         Each pair of escape sequences partitions the complete set of characters
-        into two disjoint sets. Any given character matches one, and only  one,
+        into  two disjoint sets. Any given character matches one, and only one,
         of each pair.
         These character type sequences can appear both inside and outside char-
-        acter classes. They each match one character of the  appropriate  type.
+        acter  classes.  They each match one character of the appropriate type.
-        If  the current matching point is at the end of the subject string, all
+        If the current matching point is at the end of the subject string,  all
         of them fail, since there is no character to match.
-        For compatibility with Perl, \s does not match the VT  character  (code
+        For  compatibility  with Perl, \s does not match the VT character (code
-).   This makes it different from the the POSIX "space" class. The \s
+).  This makes it different from the the POSIX "space" class. The  \s
-        characters are HT (9), LF (10), FF (12), CR (13), and  space  (32).  If
+        characters  are  HT  (9), LF (10), FF (12), CR (13), and space (32). If
         "use locale;" is included in a Perl script, \s may match the VT charac-
         ter. In PCRE, it never does.
-        In UTF-8 mode, characters with values greater than 128 never match  \d,
+        In  UTF-8 mode, characters with values greater than 128 never match \d,
         \s, or \w, and always match \D, \S, and \W. This is true even when Uni-
-        code character property support is available.  These  sequences  retain
+        code  character  property  support is available. These sequences retain
         their original meanings from before UTF-8 support was available, mainly
         for efficiency reasons.
         The sequences \h, \H, \v, and \V are Perl 5.10 features. In contrast to
-        the  other  sequences, these do match certain high-valued codepoints in
+        the other sequences, these do match certain high-valued  codepoints  in
         UTF-8 mode.  The horizontal space characters are:
           U+0009     Horizontal tab
-Line 3014 
 BACKSLASH
+Line 3059 
 BACKSLASH
           U+2029     Paragraph separator
         A "word" character is an underscore or any character less than 256 that
-        is  a  letter  or  digit.  The definition of letters and digits is con-
+        is a letter or digit. The definition of  letters  and  digits  is  con-
-        trolled by PCRE's low-valued character tables, and may vary if  locale-
+        trolled  by PCRE's low-valued character tables, and may vary if locale-
-        specific  matching is taking place (see "Locale support" in the pcreapi
+        specific matching is taking place (see "Locale support" in the  pcreapi
-        page). For example, in a French locale such  as  "fr_FR"  in  Unix-like
+        page).  For  example,  in  a French locale such as "fr_FR" in Unix-like
-        systems,  or "french" in Windows, some character codes greater than 128
+        systems, or "french" in Windows, some character codes greater than  128
-        are used for accented letters, and these are matched by \w. The use  of
+        are  used for accented letters, and these are matched by \w. The use of
         locales with Unicode is discouraged.
     Newline sequences
-        Outside  a  character class, the escape sequence \R matches any Unicode
+        Outside a character class, the escape sequence \R matches  any  Unicode
-        newline sequence. This is a Perl 5.10 feature. In non-UTF-8 mode \R  is
+        newline  sequence. This is a Perl 5.10 feature. In non-UTF-8 mode \R is
         equivalent to the following:
           (?>\r\n|\n|\x0b|\f|\r|\x85)
-        This  is  an  example  of an "atomic group", details of which are given
+        This is an example of an "atomic group", details  of  which  are  given
         below.  This particular group matches either the two-character sequence
-        CR  followed  by  LF,  or  one  of  the single characters LF (linefeed,
+        CR followed by LF, or  one  of  the  single  characters  LF  (linefeed,
         U+000A), VT (vertical tab, U+000B), FF (formfeed, U+000C), CR (carriage
         return, U+000D), or NEL (next line, U+0085). The two-character sequence
         is treated as a single unit that cannot be split.
-        In UTF-8 mode, two additional characters whose codepoints  are  greater
+        In  UTF-8  mode, two additional characters whose codepoints are greater
         than 255 are added: LS (line separator, U+2028) and PS (paragraph sepa-
-        rator, U+2029).  Unicode character property support is not  needed  for
+        rator,  U+2029).   Unicode character property support is not needed for
         these characters to be recognized.
         Inside a character class, \R matches the letter "R".
-Line 3047 
 BACKSLASH
+Line 3092 
 BACKSLASH
     Unicode character properties
         When PCRE is built with Unicode character property support, three addi-
-        tional escape sequences that match characters with specific  properties
+        tional  escape sequences that match characters with specific properties
-        are  available.   When not in UTF-8 mode, these sequences are of course
+        are available.  When not in UTF-8 mode, these sequences are  of  course
-        limited to testing characters whose codepoints are less than  256,  but
+        limited  to  testing characters whose codepoints are less than 256, but
         they do work in this mode.  The extra escape sequences are:
           \p{xx}   a character with the xx property
           \P{xx}   a character without the xx property
           \X       an extended Unicode sequence
-        The  property  names represented by xx above are limited to the Unicode
+        The property names represented by xx above are limited to  the  Unicode
         script names, the general category properties, and "Any", which matches
         any character (including newline). Other properties such as "InMusical-
-        Symbols" are not currently supported by PCRE. Note  that  \P{Any}  does
+        Symbols"  are  not  currently supported by PCRE. Note that \P{Any} does
         not match any characters, so always causes a match failure.
         Sets of Unicode characters are defined as belonging to certain scripts.
-        A character from one of these sets can be matched using a script  name.
+        A  character from one of these sets can be matched using a script name.
         For example:
           \p{Greek}
           \P{Han}
-        Those  that are not part of an identified script are lumped together as
+        Those that are not part of an identified script are lumped together  as
         "Common". The current list of scripts is:
         Arabic,  Armenian,  Balinese,  Bengali,  Bopomofo,  Braille,  Buginese,
-        Buhid,   Canadian_Aboriginal,   Cherokee,  Common,  Coptic,  Cuneiform,
+        Buhid,  Canadian_Aboriginal,  Cherokee,  Common,   Coptic,   Cuneiform,
         Cypriot, Cyrillic, Deseret, Devanagari, Ethiopic, Georgian, Glagolitic,
-        Gothic,  Greek, Gujarati, Gurmukhi, Han, Hangul, Hanunoo, Hebrew, Hira-
+        Gothic, Greek, Gujarati, Gurmukhi, Han, Hangul, Hanunoo, Hebrew,  Hira-
-        gana, Inherited, Kannada,  Katakana,  Kharoshthi,  Khmer,  Lao,  Latin,
+        gana,  Inherited,  Kannada,  Katakana,  Kharoshthi,  Khmer, Lao, Latin,
         Limbu,  Linear_B,  Malayalam,  Mongolian,  Myanmar,  New_Tai_Lue,  Nko,
-        Ogham, Old_Italic, Old_Persian, Oriya, Osmanya,  Phags_Pa,  Phoenician,
+        Ogham,  Old_Italic,  Old_Persian, Oriya, Osmanya, Phags_Pa, Phoenician,
         Runic,  Shavian,  Sinhala,  Syloti_Nagri,  Syriac,  Tagalog,  Tagbanwa,
         Tai_Le, Tamil, Telugu, Thaana, Thai, Tibetan, Tifinagh, Ugaritic, Yi.
-        Each character has exactly one general category property, specified  by
+        Each  character has exactly one general category property, specified by
         a two-letter abbreviation. For compatibility with Perl, negation can be
-        specified by including a circumflex between the opening brace  and  the
+        specified  by  including a circumflex between the opening brace and the
         property name. For example, \p{^Lu} is the same as \P{Lu}.
         If only one letter is specified with \p or \P, it includes all the gen-
-        eral category properties that start with that letter. In this case,  in
+        eral  category properties that start with that letter. In this case, in
-        the  absence of negation, the curly brackets in the escape sequence are
+        the absence of negation, the curly brackets in the escape sequence  are
         optional; these two examples have the same effect:
           \p{L}
-Line 3141 
 BACKSLASH
+Line 3186 
 BACKSLASH
           Zp    Paragraph separator
           Zs    Space separator
-        The special property L& is also supported: it matches a character  that
+        The  special property L& is also supported: it matches a character that
-        has  the  Lu,  Ll, or Lt property, in other words, a letter that is not
+        has the Lu, Ll, or Lt property, in other words, a letter  that  is  not
         classified as a modifier or "other".
-        The long synonyms for these properties  that  Perl  supports  (such  as
+        The  Cs  (Surrogate)  property  applies only to characters in the range
-        \p{Letter})  are  not  supported by PCRE, nor is it permitted to prefix
+        U+D800 to U+DFFF. Such characters are not valid in UTF-8  strings  (see
+        RFC 3629) and so cannot be tested by PCRE, unless UTF-8 validity check-
+        ing has been turned off (see the discussion  of  PCRE_NO_UTF8_CHECK  in
+        the pcreapi page).
+        The  long  synonyms  for  these  properties that Perl supports (such as
+        \p{Letter}) are not supported by PCRE, nor is it  permitted  to  prefix
         any of these properties with "Is".
         No character that is in the Unicode table has the Cn (unassigned) prop-
         erty.  Instead, this property is assumed for any code point that is not
         in the Unicode table.
-        Specifying caseless matching does not affect  these  escape  sequences.
+        Specifying  caseless  matching  does not affect these escape sequences.
         For example, \p{Lu} always matches only upper case letters.
-        The  \X  escape  matches  any number of Unicode characters that form an
+        The \X escape matches any number of Unicode  characters  that  form  an
         extended Unicode sequence. \X is equivalent to
           (?>\PM\pM*)
-        That is, it matches a character without the "mark"  property,  followed
+        That  is,  it matches a character without the "mark" property, followed
-        by  zero  or  more  characters with the "mark" property, and treats the
+        by zero or more characters with the "mark"  property,  and  treats  the
-        sequence as an atomic group (see below).  Characters  with  the  "mark"
+        sequence  as  an  atomic group (see below).  Characters with the "mark"
-        property  are  typically  accents  that affect the preceding character.
+        property are typically accents that  affect  the  preceding  character.
-        None of them have codepoints less than 256, so  in  non-UTF-8  mode  \X
+        None  of  them  have  codepoints less than 256, so in non-UTF-8 mode \X
         matches any one character.
-        Matching  characters  by Unicode property is not fast, because PCRE has
+        Matching characters by Unicode property is not fast, because  PCRE  has
-        to search a structure that contains  data  for  over  fifteen  thousand
+        to  search  a  structure  that  contains data for over fifteen thousand
         characters. That is why the traditional escape sequences such as \d and
         \w do not use Unicode properties in PCRE.
     Resetting the match start
         The escape sequence \K, which is a Perl 5.10 feature, causes any previ-
-        ously  matched  characters  not  to  be  included  in the final matched
+        ously matched characters not  to  be  included  in  the  final  matched
         sequence. For example, the pattern:
           foo\Kbar
-        matches "foobar", but reports that it has matched "bar".  This  feature
+        matches  "foobar",  but reports that it has matched "bar". This feature
-        is  similar  to  a lookbehind assertion (described below).  However, in
+        is similar to a lookbehind assertion (described  below).   However,  in
-        this case, the part of the subject before the real match does not  have
+        this  case, the part of the subject before the real match does not have
-        to  be of fixed length, as lookbehind assertions do. The use of \K does
+        to be of fixed length, as lookbehind assertions do. The use of \K  does
-        not interfere with the setting of captured  substrings.   For  example,
+        not  interfere  with  the setting of captured substrings.  For example,
         when the pattern
           (foo)\Kbar
-Line 3194 
 BACKSLASH
+Line 3245 
 BACKSLASH
     Simple assertions
-        The  final use of backslash is for certain simple assertions. An asser-
+        The final use of backslash is for certain simple assertions. An  asser-
-        tion specifies a condition that has to be met at a particular point  in
+        tion  specifies a condition that has to be met at a particular point in
-        a  match, without consuming any characters from the subject string. The
+        a match, without consuming any characters from the subject string.  The
-        use of subpatterns for more complicated assertions is described  below.
+        use  of subpatterns for more complicated assertions is described below.
         The backslashed assertions are:
           \b     matches at a word boundary
-Line 3208 
 BACKSLASH
+Line 3259 
 BACKSLASH
           \z     matches only at the end of the subject
           \G     matches at the first matching position in the subject
-        These  assertions may not appear in character classes (but note that \b
+        These assertions may not appear in character classes (but note that  \b
         has a different meaning, namely the backspace character, inside a char-
         acter class).
-        A  word  boundary is a position in the subject string where the current
+        A word boundary is a position in the subject string where  the  current
-        character and the previous character do not both match \w or  \W  (i.e.
+        character  and  the previous character do not both match \w or \W (i.e.
-        one  matches  \w  and the other matches \W), or the start or end of the
+        one matches \w and the other matches \W), or the start or  end  of  the
         string if the first or last character matches \w, respectively.
-        The \A, \Z, and \z assertions differ from  the  traditional  circumflex
+        The  \A,  \Z,  and \z assertions differ from the traditional circumflex
         and dollar (described in the next section) in that they only ever match
-        at the very start and end of the subject string, whatever  options  are
+        at  the  very start and end of the subject string, whatever options are
-        set.  Thus,  they are independent of multiline mode. These three asser-
+        set. Thus, they are independent of multiline mode. These  three  asser-
         tions are not affected by the PCRE_NOTBOL or PCRE_NOTEOL options, which
-        affect  only the behaviour of the circumflex and dollar metacharacters.
+        affect only the behaviour of the circumflex and dollar  metacharacters.
-        However, if the startoffset argument of pcre_exec() is non-zero,  indi-
+        However,  if the startoffset argument of pcre_exec() is non-zero, indi-
         cating that matching is to start at a point other than the beginning of
-        the subject, \A can never match. The difference between \Z  and  \z  is
+        the  subject,  \A  can never match. The difference between \Z and \z is
         that \Z matches before a newline at the end of the string as well as at
         the very end, whereas \z matches only at the end.
-        The \G assertion is true only when the current matching position is  at
+        The  \G assertion is true only when the current matching position is at
-        the  start point of the match, as specified by the startoffset argument
+        the start point of the match, as specified by the startoffset  argument
-        of pcre_exec(). It differs from \A when the  value  of  startoffset  is
+        of  pcre_exec().  It  differs  from \A when the value of startoffset is
-        non-zero.  By calling pcre_exec() multiple times with appropriate argu-
+        non-zero. By calling pcre_exec() multiple times with appropriate  argu-
         ments, you can mimic Perl's /g option, and it is in this kind of imple-
         mentation where \G can be useful.
-        Note,  however,  that  PCRE's interpretation of \G, as the start of the
+        Note, however, that PCRE's interpretation of \G, as the  start  of  the
         current match, is subtly different from Perl's, which defines it as the
-        end  of  the  previous  match. In Perl, these can be different when the
+        end of the previous match. In Perl, these can  be  different  when  the
-        previously matched string was empty. Because PCRE does just  one  match
+        previously  matched  string was empty. Because PCRE does just one match
         at a time, it cannot reproduce this behaviour.
-        If  all  the alternatives of a pattern begin with \G, the expression is
+        If all the alternatives of a pattern begin with \G, the  expression  is
         anchored to the starting match position, and the "anchored" flag is set
         in the compiled regular expression.
-Line 3250 
 BACKSLASH
+Line 3301 
 BACKSLASH
  CIRCUMFLEX AND DOLLAR
         Outside a character class, in the default matching mode, the circumflex
-        character is an assertion that is true only  if  the  current  matching
+        character  is  an  assertion  that is true only if the current matching
-        point  is  at the start of the subject string. If the startoffset argu-
+        point is at the start of the subject string. If the  startoffset  argu-
-        ment of pcre_exec() is non-zero, circumflex  can  never  match  if  the
+        ment  of  pcre_exec()  is  non-zero,  circumflex can never match if the
-        PCRE_MULTILINE  option  is  unset. Inside a character class, circumflex
+        PCRE_MULTILINE option is unset. Inside a  character  class,  circumflex
         has an entirely different meaning (see below).
-        Circumflex need not be the first character of the pattern if  a  number
+        Circumflex  need  not be the first character of the pattern if a number
-        of  alternatives are involved, but it should be the first thing in each
+        of alternatives are involved, but it should be the first thing in  each
-        alternative in which it appears if the pattern is ever  to  match  that
+        alternative  in  which  it appears if the pattern is ever to match that
-        branch.  If all possible alternatives start with a circumflex, that is,
+        branch. If all possible alternatives start with a circumflex, that  is,
-        if the pattern is constrained to match only at the start  of  the  sub-
+        if  the  pattern  is constrained to match only at the start of the sub-
-        ject,  it  is  said  to be an "anchored" pattern. (There are also other
+        ject, it is said to be an "anchored" pattern.  (There  are  also  other
         constructs that can cause a pattern to be anchored.)
-        A dollar character is an assertion that is true  only  if  the  current
+        A  dollar  character  is  an assertion that is true only if the current
-        matching  point  is  at  the  end of the subject string, or immediately
+        matching point is at the end of  the  subject  string,  or  immediately
         before a newline at the end of the string (by default). Dollar need not
-        be  the  last  character of the pattern if a number of alternatives are
+        be the last character of the pattern if a number  of  alternatives  are
-        involved, but it should be the last item in  any  branch  in  which  it
+        involved,  but  it  should  be  the last item in any branch in which it
         appears. Dollar has no special meaning in a character class.
-        The  meaning  of  dollar  can be changed so that it matches only at the
+        The meaning of dollar can be changed so that it  matches  only  at  the
-        very end of the string, by setting the  PCRE_DOLLAR_ENDONLY  option  at
+        very  end  of  the string, by setting the PCRE_DOLLAR_ENDONLY option at
         compile time. This does not affect the \Z assertion.
         The meanings of the circumflex and dollar characters are changed if the
-        PCRE_MULTILINE option is set. When  this  is  the  case,  a  circumflex
+        PCRE_MULTILINE  option  is  set.  When  this  is the case, a circumflex
-        matches  immediately after internal newlines as well as at the start of
+        matches immediately after internal newlines as well as at the start  of
-        the subject string. It does not match after a  newline  that  ends  the
+        the  subject  string.  It  does not match after a newline that ends the
-        string.  A dollar matches before any newlines in the string, as well as
+        string. A dollar matches before any newlines in the string, as well  as
-        at the very end, when PCRE_MULTILINE is set. When newline is  specified
+        at  the very end, when PCRE_MULTILINE is set. When newline is specified
-        as  the  two-character  sequence CRLF, isolated CR and LF characters do
+        as the two-character sequence CRLF, isolated CR and  LF  characters  do
         not indicate newlines.
-        For example, the pattern /^abc$/ matches the subject string  "def\nabc"
+        For  example, the pattern /^abc$/ matches the subject string "def\nabc"
-        (where  \n  represents a newline) in multiline mode, but not otherwise.
+        (where \n represents a newline) in multiline mode, but  not  otherwise.
-        Consequently, patterns that are anchored in single  line  mode  because
+        Consequently,  patterns  that  are anchored in single line mode because
-        all  branches  start  with  ^ are not anchored in multiline mode, and a
+        all branches start with ^ are not anchored in  multiline  mode,  and  a
-        match for circumflex is  possible  when  the  startoffset  argument  of
+        match  for  circumflex  is  possible  when  the startoffset argument of
-        pcre_exec()  is  non-zero. The PCRE_DOLLAR_ENDONLY option is ignored if
+        pcre_exec() is non-zero. The PCRE_DOLLAR_ENDONLY option is  ignored  if
         PCRE_MULTILINE is set.
-        Note that the sequences \A, \Z, and \z can be used to match  the  start
+        Note  that  the sequences \A, \Z, and \z can be used to match the start
-        and  end of the subject in both modes, and if all branches of a pattern
+        and end of the subject in both modes, and if all branches of a  pattern
-        start with \A it is always anchored, whether or not  PCRE_MULTILINE  is
+        start  with  \A it is always anchored, whether or not PCRE_MULTILINE is
         set.
  FULL STOP (PERIOD, DOT)
         Outside a character class, a dot in the pattern matches any one charac-
-        ter in the subject string except (by default) a character  that  signi-
+        ter  in  the subject string except (by default) a character that signi-
-        fies  the  end  of  a line. In UTF-8 mode, the matched character may be
+        fies the end of a line. In UTF-8 mode, the  matched  character  may  be
         more than one byte long.
-        When a line ending is defined as a single character, dot never  matches
+        When  a line ending is defined as a single character, dot never matches
-        that  character; when the two-character sequence CRLF is used, dot does
+        that character; when the two-character sequence CRLF is used, dot  does
-        not match CR if it is immediately followed  by  LF,  but  otherwise  it
+        not  match  CR  if  it  is immediately followed by LF, but otherwise it
-        matches  all characters (including isolated CRs and LFs). When any Uni-
+        matches all characters (including isolated CRs and LFs). When any  Uni-
-        code line endings are being recognized, dot does not match CR or LF  or
+        code  line endings are being recognized, dot does not match CR or LF or
         any of the other line ending characters.
-        The  behaviour  of  dot  with regard to newlines can be changed. If the
+        The behaviour of dot with regard to newlines can  be  changed.  If  the
-        PCRE_DOTALL option is set, a dot matches  any  one  character,  without
+        PCRE_DOTALL  option  is  set,  a dot matches any one character, without
         exception. If the two-character sequence CRLF is present in the subject
         string, it takes two dots to match it.
-        The handling of dot is entirely independent of the handling of  circum-
+        The  handling of dot is entirely independent of the handling of circum-
-        flex  and  dollar,  the  only relationship being that they both involve
+        flex and dollar, the only relationship being  that  they  both  involve
         newlines. Dot has no special meaning in a character class.
  MATCHING A SINGLE BYTE
         Outside a character class, the escape sequence \C matches any one byte,
-        both  in  and  out  of  UTF-8 mode. Unlike a dot, it always matches any
+        both in and out of UTF-8 mode. Unlike a  dot,  it  always  matches  any
-        line-ending characters. The feature is provided in  Perl  in  order  to
+        line-ending  characters.  The  feature  is provided in Perl in order to
-        match  individual bytes in UTF-8 mode. Because it breaks up UTF-8 char-
+        match individual bytes in UTF-8 mode. Because it breaks up UTF-8  char-
-        acters into individual bytes, what remains in the string may be a  mal-
+        acters  into individual bytes, what remains in the string may be a mal-
-        formed  UTF-8  string.  For this reason, the \C escape sequence is best
+        formed UTF-8 string. For this reason, the \C escape  sequence  is  best
         avoided.
-        PCRE does not allow \C to appear in  lookbehind  assertions  (described
+        PCRE  does  not  allow \C to appear in lookbehind assertions (described
-        below),  because  in UTF-8 mode this would make it impossible to calcu-
+        below), because in UTF-8 mode this would make it impossible  to  calcu-
         late the length of the lookbehind.
-Line 3342 
 SQUARE BRACKETS AND CHARACTER CLASSES
+Line 3393 
 SQUARE BRACKETS AND CHARACTER CLASSES
         An opening square bracket introduces a character class, terminated by a
         closing square bracket. A closing square bracket on its own is not spe-
         cial. If a closing square bracket is required as a member of the class,
-        it  should  be  the first data character in the class (after an initial
+        it should be the first data character in the class  (after  an  initial
         circumflex, if present) or escaped with a backslash.
-        A character class matches a single character in the subject.  In  UTF-8
+        A  character  class matches a single character in the subject. In UTF-8
-        mode,  the character may occupy more than one byte. A matched character
+        mode, the character may occupy more than one byte. A matched  character
         must be in the set of characters defined by the class, unless the first
-        character  in  the  class definition is a circumflex, in which case the
+        character in the class definition is a circumflex, in  which  case  the
-        subject character must not be in the set defined by  the  class.  If  a
+        subject  character  must  not  be in the set defined by the class. If a
-        circumflex  is actually required as a member of the class, ensure it is
+        circumflex is actually required as a member of the class, ensure it  is
         not the first character, or escape it with a backslash.
-        For example, the character class [aeiou] matches any lower case  vowel,
+        For  example, the character class [aeiou] matches any lower case vowel,
-        while  [^aeiou]  matches  any character that is not a lower case vowel.
+        while [^aeiou] matches any character that is not a  lower  case  vowel.
         Note that a circumflex is just a convenient notation for specifying the
-        characters  that  are in the class by enumerating those that are not. A
+        characters that are in the class by enumerating those that are  not.  A
-        class that starts with a circumflex is not an assertion: it still  con-
+        class  that starts with a circumflex is not an assertion: it still con-
-        sumes  a  character  from the subject string, and therefore it fails if
+        sumes a character from the subject string, and therefore  it  fails  if
         the current pointer is at the end of the string.
-        In UTF-8 mode, characters with values greater than 255 can be  included
+        In  UTF-8 mode, characters with values greater than 255 can be included
-        in  a  class as a literal string of bytes, or by using the \x{ escaping
+        in a class as a literal string of bytes, or by using the  \x{  escaping
         mechanism.
-        When caseless matching is set, any letters in a  class  represent  both
+        When  caseless  matching  is set, any letters in a class represent both
-        their  upper  case  and lower case versions, so for example, a caseless
+        their upper case and lower case versions, so for  example,  a  caseless
-        [aeiou] matches "A" as well as "a", and a caseless  [^aeiou]  does  not
+        [aeiou]  matches  "A"  as well as "a", and a caseless [^aeiou] does not
-        match  "A", whereas a caseful version would. In UTF-8 mode, PCRE always
+        match "A", whereas a caseful version would. In UTF-8 mode, PCRE  always
-        understands the concept of case for characters whose  values  are  less
+        understands  the  concept  of case for characters whose values are less
-        than  128, so caseless matching is always possible. For characters with
+        than 128, so caseless matching is always possible. For characters  with
-        higher values, the concept of case is supported  if  PCRE  is  compiled
+        higher  values,  the  concept  of case is supported if PCRE is compiled
-        with  Unicode  property support, but not otherwise.  If you want to use
+        with Unicode property support, but not otherwise.  If you want  to  use
-        caseless matching for characters 128 and above, you  must  ensure  that
+        caseless  matching  for  characters 128 and above, you must ensure that
-        PCRE  is  compiled  with Unicode property support as well as with UTF-8
+        PCRE is compiled with Unicode property support as well  as  with  UTF-8
         support.
-        Characters that might indicate line breaks are  never  treated  in  any
+        Characters  that  might  indicate  line breaks are never treated in any
-        special  way  when  matching  character  classes,  whatever line-ending
+        special way  when  matching  character  classes,  whatever  line-ending
-        sequence is in  use,  and  whatever  setting  of  the  PCRE_DOTALL  and
+        sequence  is  in  use,  and  whatever  setting  of  the PCRE_DOTALL and
         PCRE_MULTILINE options is used. A class such as [^a] always matches one
         of these characters.
-        The minus (hyphen) character can be used to specify a range of  charac-
+        The  minus (hyphen) character can be used to specify a range of charac-
-        ters  in  a  character  class.  For  example,  [d-m] matches any letter
+        ters in a character  class.  For  example,  [d-m]  matches  any  letter
-        between d and m, inclusive. If a  minus  character  is  required  in  a
+        between  d  and  m,  inclusive.  If  a minus character is required in a
-        class,  it  must  be  escaped  with a backslash or appear in a position
+        class, it must be escaped with a backslash  or  appear  in  a  position
-        where it cannot be interpreted as indicating a range, typically as  the
+        where  it cannot be interpreted as indicating a range, typically as the
         first or last character in the class.
         It is not possible to have the literal character "]" as the end charac-
-        ter of a range. A pattern such as [W-]46] is interpreted as a class  of
+        ter  of a range. A pattern such as [W-]46] is interpreted as a class of
-        two  characters ("W" and "-") followed by a literal string "46]", so it
+        two characters ("W" and "-") followed by a literal string "46]", so  it
-        would match "W46]" or "-46]". However, if the "]"  is  escaped  with  a
+        would  match  "W46]"  or  "-46]". However, if the "]" is escaped with a
-        backslash  it is interpreted as the end of range, so [W-\]46] is inter-
+        backslash it is interpreted as the end of range, so [W-\]46] is  inter-
-        preted as a class containing a range followed by two other  characters.
+        preted  as a class containing a range followed by two other characters.
-        The  octal or hexadecimal representation of "]" can also be used to end
+        The octal or hexadecimal representation of "]" can also be used to  end
         a range.
-        Ranges operate in the collating sequence of character values. They  can
+        Ranges  operate in the collating sequence of character values. They can
-        also   be  used  for  characters  specified  numerically,  for  example
+        also  be  used  for  characters  specified  numerically,  for   example
-        [\000-\037]. In UTF-8 mode, ranges can include characters whose  values
+        [\000-\037].  In UTF-8 mode, ranges can include characters whose values
         are greater than 255, for example [\x{100}-\x{2ff}].
         If a range that includes letters is used when caseless matching is set,
         it matches the letters in either case. For example, [W-c] is equivalent
-        to  [][\\^_`wxyzabc],  matched  caselessly,  and  in non-UTF-8 mode, if
+        to [][\\^_`wxyzabc], matched caselessly,  and  in  non-UTF-8  mode,  if
-        character tables for a French locale are in  use,  [\xc8-\xcb]  matches
+        character  tables  for  a French locale are in use, [\xc8-\xcb] matches
-        accented  E  characters in both cases. In UTF-8 mode, PCRE supports the
+        accented E characters in both cases. In UTF-8 mode, PCRE  supports  the
-        concept of case for characters with values greater than 128  only  when
+        concept  of  case for characters with values greater than 128 only when
         it is compiled with Unicode property support.
-        The  character types \d, \D, \p, \P, \s, \S, \w, and \W may also appear
+        The character types \d, \D, \p, \P, \s, \S, \w, and \W may also  appear
-        in a character class, and add the characters that  they  match  to  the
+        in  a  character  class,  and add the characters that they match to the
         class. For example, [\dABCDEF] matches any hexadecimal digit. A circum-
-        flex can conveniently be used with the upper case  character  types  to
+        flex  can  conveniently  be used with the upper case character types to
-        specify  a  more  restricted  set of characters than the matching lower
+        specify a more restricted set of characters  than  the  matching  lower
-        case type. For example, the class [^\W_] matches any letter  or  digit,
+        case  type.  For example, the class [^\W_] matches any letter or digit,
         but not underscore.
-        The  only  metacharacters  that are recognized in character classes are
+        The only metacharacters that are recognized in  character  classes  are
-        backslash, hyphen (only where it can be  interpreted  as  specifying  a
+        backslash,  hyphen  (only  where  it can be interpreted as specifying a
-        range),  circumflex  (only  at the start), opening square bracket (only
+        range), circumflex (only at the start), opening  square  bracket  (only
-        when it can be interpreted as introducing a POSIX class name - see  the
+        when  it can be interpreted as introducing a POSIX class name - see the
-        next  section),  and  the  terminating closing square bracket. However,
+        next section), and the terminating  closing  square  bracket.  However,
         escaping other non-alphanumeric characters does no harm.
  POSIX CHARACTER CLASSES
         Perl supports the POSIX notation for character classes. This uses names
-        enclosed  by  [: and :] within the enclosing square brackets. PCRE also
+        enclosed by [: and :] within the enclosing square brackets.  PCRE  also
         supports this notation. For example,
           [01[:alpha:]%]
-Line 3454 
 POSIX CHARACTER CLASSES
+Line 3505 
 POSIX CHARACTER CLASSES
           word     "word" characters (same as \w)
           xdigit   hexadecimal digits
-        The  "space" characters are HT (9), LF (10), VT (11), FF (12), CR (13),
+        The "space" characters are HT (9), LF (10), VT (11), FF (12), CR  (13),
-        and space (32). Notice that this list includes the VT  character  (code
+        and  space  (32). Notice that this list includes the VT character (code
 ). This makes "space" different to \s, which does not include VT (for
         Perl compatibility).
-        The name "word" is a Perl extension, and "blank"  is  a  GNU  extension
+        The  name  "word"  is  a Perl extension, and "blank" is a GNU extension
-        from  Perl  5.8. Another Perl extension is negation, which is indicated
+        from Perl 5.8. Another Perl extension is negation, which  is  indicated
         by a ^ character after the colon. For example,
           [12[:^digit:]]
-        matches "1", "2", or any non-digit. PCRE (and Perl) also recognize  the
+        matches  "1", "2", or any non-digit. PCRE (and Perl) also recognize the
         POSIX syntax [.ch.] and [=ch=] where "ch" is a "collating element", but
         these are not supported, and an error is given if they are encountered.
-Line 3475 
 POSIX CHARACTER CLASSES
+Line 3526 
 POSIX CHARACTER CLASSES
  VERTICAL BAR
-        Vertical bar characters are used to separate alternative patterns.  For
+        Vertical  bar characters are used to separate alternative patterns. For
         example, the pattern
           gilbert|sullivan
-        matches  either "gilbert" or "sullivan". Any number of alternatives may
+        matches either "gilbert" or "sullivan". Any number of alternatives  may
-        appear, and an empty  alternative  is  permitted  (matching  the  empty
+        appear,  and  an  empty  alternative  is  permitted (matching the empty
         string). The matching process tries each alternative in turn, from left
-        to right, and the first one that succeeds is used. If the  alternatives
+        to  right, and the first one that succeeds is used. If the alternatives
-        are  within a subpattern (defined below), "succeeds" means matching the
+        are within a subpattern (defined below), "succeeds" means matching  the
-        rest of the main pattern as well as the alternative in the  subpattern.
+        rest  of the main pattern as well as the alternative in the subpattern.
  INTERNAL OPTION SETTING
-        The  settings  of  the  PCRE_CASELESS, PCRE_MULTILINE, PCRE_DOTALL, and
+        The settings of the  PCRE_CASELESS,  PCRE_MULTILINE,  PCRE_DOTALL,  and
-        PCRE_EXTENDED options can be changed  from  within  the  pattern  by  a
+        PCRE_EXTENDED  options  can  be  changed  from  within the pattern by a
-        sequence  of  Perl  option  letters  enclosed between "(?" and ")". The
+        sequence of Perl option letters enclosed  between  "(?"  and  ")".  The
         option letters are
           i  for PCRE_CASELESS
-Line 3502 
 INTERNAL OPTION SETTING
+Line 3553 
 INTERNAL OPTION SETTING
         For example, (?im) sets caseless, multiline matching. It is also possi-
         ble to unset these options by preceding the letter with a hyphen, and a
-        combined setting and unsetting such as (?im-sx), which sets  PCRE_CASE-
+        combined  setting and unsetting such as (?im-sx), which sets PCRE_CASE-
-        LESS  and PCRE_MULTILINE while unsetting PCRE_DOTALL and PCRE_EXTENDED,
+        LESS and PCRE_MULTILINE while unsetting PCRE_DOTALL and  PCRE_EXTENDED,
-        is also permitted. If a  letter  appears  both  before  and  after  the
+        is  also  permitted.  If  a  letter  appears  both before and after the
         hyphen, the option is unset.
-        When  an option change occurs at top level (that is, not inside subpat-
+        When an option change occurs at top level (that is, not inside  subpat-
-        tern parentheses), the change applies to the remainder of  the  pattern
+        tern  parentheses),  the change applies to the remainder of the pattern
         that follows.  If the change is placed right at the start of a pattern,
         PCRE extracts it into the global options (and it will therefore show up
         in data extracted by the pcre_fullinfo() function).
-        An  option  change  within a subpattern (see below for a description of
+        An option change within a subpattern (see below for  a  description  of
         subpatterns) affects only that part of the current pattern that follows
         it, so
           (a(?i)b)c
         matches abc and aBc and no other strings (assuming PCRE_CASELESS is not
-        used).  By this means, options can be made to have  different  settings
+        used).   By  this means, options can be made to have different settings
-        in  different parts of the pattern. Any changes made in one alternative
+        in different parts of the pattern. Any changes made in one  alternative
-        do carry on into subsequent branches within the  same  subpattern.  For
+        do  carry  on  into subsequent branches within the same subpattern. For
         example,
           (a(?i)b|c)
-        matches  "ab",  "aB",  "c",  and "C", even though when matching "C" the
+        matches "ab", "aB", "c", and "C", even though  when  matching  "C"  the
-        first branch is abandoned before the option setting.  This  is  because
+        first  branch  is  abandoned before the option setting. This is because
-        the  effects  of option settings happen at compile time. There would be
+        the effects of option settings happen at compile time. There  would  be
         some very weird behaviour otherwise.
-        The PCRE-specific options PCRE_DUPNAMES, PCRE_UNGREEDY, and  PCRE_EXTRA
+        The  PCRE-specific options PCRE_DUPNAMES, PCRE_UNGREEDY, and PCRE_EXTRA
-        can  be changed in the same way as the Perl-compatible options by using
+        can be changed in the same way as the Perl-compatible options by  using
         the characters J, U and X respectively.
-Line 3546 
 SUBPATTERNS
+Line 3597 
 SUBPATTERNS
           cat(aract|erpillar|)
-        matches  one  of the words "cat", "cataract", or "caterpillar". Without
+        matches one of the words "cat", "cataract", or  "caterpillar".  Without
-        the parentheses, it would match  "cataract",  "erpillar"  or  an  empty
+        the  parentheses,  it  would  match  "cataract", "erpillar" or an empty
         string.
-.  It  sets  up  the  subpattern as a capturing subpattern. This means
+. It sets up the subpattern as  a  capturing  subpattern.  This  means
-        that, when the whole pattern  matches,  that  portion  of  the  subject
+        that,  when  the  whole  pattern  matches,  that portion of the subject
         string that matched the subpattern is passed back to the caller via the
-        ovector argument of pcre_exec(). Opening parentheses are  counted  from
+        ovector  argument  of pcre_exec(). Opening parentheses are counted from
-        left  to  right  (starting  from 1) to obtain numbers for the capturing
+        left to right (starting from 1) to obtain  numbers  for  the  capturing
         subpatterns.
-        For example, if the string "the red king" is matched against  the  pat-
+        For  example,  if the string "the red king" is matched against the pat-
         tern
           the ((red|white) (king|queen))
-Line 3565 
 SUBPATTERNS
+Line 3616 
 SUBPATTERNS
         the captured substrings are "red king", "red", and "king", and are num-
         bered 1, 2, and 3, respectively.
-        The fact that plain parentheses fulfil  two  functions  is  not  always
+        The  fact  that  plain  parentheses  fulfil two functions is not always
-        helpful.   There are often times when a grouping subpattern is required
+        helpful.  There are often times when a grouping subpattern is  required
-        without a capturing requirement. If an opening parenthesis is  followed
+        without  a capturing requirement. If an opening parenthesis is followed
-        by  a question mark and a colon, the subpattern does not do any captur-
+        by a question mark and a colon, the subpattern does not do any  captur-
-        ing, and is not counted when computing the  number  of  any  subsequent
+        ing,  and  is  not  counted when computing the number of any subsequent
-        capturing  subpatterns. For example, if the string "the white queen" is
+        capturing subpatterns. For example, if the string "the white queen"  is
         matched against the pattern
           the ((?:red|white) (king|queen))
-Line 3578 
 SUBPATTERNS
+Line 3629 
 SUBPATTERNS
         the captured substrings are "white queen" and "queen", and are numbered
 and 2. The maximum number of capturing subpatterns is 65535.
-        As  a  convenient shorthand, if any option settings are required at the
+        As a convenient shorthand, if any option settings are required  at  the
-        start of a non-capturing subpattern,  the  option  letters  may  appear
+        start  of  a  non-capturing  subpattern,  the option letters may appear
         between the "?" and the ":". Thus the two patterns
           (?i:saturday|sunday)
           (?:(?i)saturday|sunday)
         match exactly the same set of strings. Because alternative branches are
-        tried from left to right, and options are not reset until  the  end  of
+        tried  from  left  to right, and options are not reset until the end of
-        the  subpattern is reached, an option setting in one branch does affect
+        the subpattern is reached, an option setting in one branch does  affect
-        subsequent branches, so the above patterns match "SUNDAY"  as  well  as
+        subsequent  branches,  so  the above patterns match "SUNDAY" as well as
         "Saturday".
  DUPLICATE SUBPATTERN NUMBERS
         Perl 5.10 introduced a feature whereby each alternative in a subpattern
-        uses the same numbers for its capturing parentheses. Such a  subpattern
+        uses  the same numbers for its capturing parentheses. Such a subpattern
-        starts  with (?| and is itself a non-capturing subpattern. For example,
+        starts with (?| and is itself a non-capturing subpattern. For  example,
         consider this pattern:
           (?|(Sat)ur|(Sun))day
-        Because the two alternatives are inside a (?| group, both sets of  cap-
+        Because  the two alternatives are inside a (?| group, both sets of cap-
-        turing  parentheses  are  numbered one. Thus, when the pattern matches,
+        turing parentheses are numbered one. Thus, when  the  pattern  matches,
-        you can look at captured substring number  one,  whichever  alternative
+        you  can  look  at captured substring number one, whichever alternative
-        matched.  This  construct  is useful when you want to capture part, but
+        matched. This construct is useful when you want to  capture  part,  but
         not all, of one of a number of alternatives. Inside a (?| group, paren-
-        theses  are  numbered as usual, but the number is reset at the start of
+        theses are numbered as usual, but the number is reset at the  start  of
-        each branch. The numbers of any capturing buffers that follow the  sub-
+        each  branch. The numbers of any capturing buffers that follow the sub-
-        pattern  start after the highest number used in any branch. The follow-
+        pattern start after the highest number used in any branch. The  follow-
-        ing example is taken from the Perl documentation.  The  numbers  under-
+        ing  example  is taken from the Perl documentation.  The numbers under-
         neath show in which buffer the captured content will be stored.
           # before  ---------------branch-reset----------- after
           / ( a )  (?| x ( y ) z | (p (q) r) | (t) u (v) ) ( z ) /x
           # 1            2         2  3        2     3     4
-        A  backreference  or  a  recursive call to a numbered subpattern always
+        A backreference or a recursive call to  a  numbered  subpattern  always
         refers to the first one in the pattern with the given number.
-        An alternative approach to using this "branch reset" feature is to  use
+        An  alternative approach to using this "branch reset" feature is to use
         duplicate named subpatterns, as described in the next section.
  NAMED SUBPATTERNS
-        Identifying  capturing  parentheses  by number is simple, but it can be
+        Identifying capturing parentheses by number is simple, but  it  can  be
-        very hard to keep track of the numbers in complicated  regular  expres-
+        very  hard  to keep track of the numbers in complicated regular expres-
-        sions.  Furthermore,  if  an  expression  is  modified, the numbers may
+        sions. Furthermore, if an  expression  is  modified,  the  numbers  may
-        change. To help with this difficulty, PCRE supports the naming of  sub-
+        change.  To help with this difficulty, PCRE supports the naming of sub-
         patterns. This feature was not added to Perl until release 5.10. Python
-        had the feature earlier, and PCRE introduced it at release  4.0,  using
+        had  the  feature earlier, and PCRE introduced it at release 4.0, using
-        the  Python syntax. PCRE now supports both the Perl and the Python syn-
+        the Python syntax. PCRE now supports both the Perl and the Python  syn-
         tax.
-        In PCRE, a subpattern can be named in one of three  ways:  (?<name>...)
+        In  PCRE,  a subpattern can be named in one of three ways: (?<name>...)
-        or  (?'name'...)  as in Perl, or (?P<name>...) as in Python. References
+        or (?'name'...) as in Perl, or (?P<name>...) as in  Python.  References
         to capturing parentheses from other parts of the pattern, such as back-
-        references,  recursion,  and conditions, can be made by name as well as
+        references, recursion, and conditions, can be made by name as  well  as
         by number.
-        Names consist of up to  32  alphanumeric  characters  and  underscores.
+        Names  consist  of  up  to  32 alphanumeric characters and underscores.
-        Named  capturing  parentheses  are  still  allocated numbers as well as
+        Named capturing parentheses are still  allocated  numbers  as  well  as
-        names, exactly as if the names were not present. The PCRE API  provides
+        names,  exactly as if the names were not present. The PCRE API provides
         function calls for extracting the name-to-number translation table from
         a compiled pattern. There is also a convenience function for extracting
         a captured substring by name.
-        By  default, a name must be unique within a pattern, but it is possible
+        By default, a name must be unique within a pattern, but it is  possible
         to relax this constraint by setting the PCRE_DUPNAMES option at compile
-        time.  This  can  be useful for patterns where only one instance of the
+        time. This can be useful for patterns where only one  instance  of  the
-        named parentheses can match. Suppose you want to match the  name  of  a
+        named  parentheses  can  match. Suppose you want to match the name of a
-        weekday,  either as a 3-letter abbreviation or as the full name, and in
+        weekday, either as a 3-letter abbreviation or as the full name, and  in
         both cases you want to extract the abbreviation. This pattern (ignoring
         the line breaks) does the job:
-Line 3661 
 NAMED SUBPATTERNS
+Line 3712 
 NAMED SUBPATTERNS
           (?<DN>Thu)(?:rsday)?|
           (?<DN>Sat)(?:urday)?
-        There  are  five capturing substrings, but only one is ever set after a
+        There are five capturing substrings, but only one is ever set  after  a
         match.  (An alternative way of solving this problem is to use a "branch
         reset" subpattern, as described in the previous section.)
-        The  convenience  function  for extracting the data by name returns the
+        The convenience function for extracting the data by  name  returns  the
-        substring for the first (and in this example, the only)  subpattern  of
+        substring  for  the first (and in this example, the only) subpattern of
-        that  name  that  matched.  This saves searching to find which numbered
+        that name that matched. This saves searching  to  find  which  numbered
-        subpattern it was. If you make a reference to a non-unique  named  sub-
+        subpattern  it  was. If you make a reference to a non-unique named sub-
-        pattern  from elsewhere in the pattern, the one that corresponds to the
+        pattern from elsewhere in the pattern, the one that corresponds to  the
-        lowest number is used. For further details of the interfaces  for  han-
+        lowest  number  is used. For further details of the interfaces for han-
         dling named subpatterns, see the pcreapi documentation.
  REPETITION
-        Repetition  is  specified  by  quantifiers, which can follow any of the
+        Repetition is specified by quantifiers, which can  follow  any  of  the
         following items:
           a literal data character
-Line 3689 
 REPETITION
+Line 3740 
 REPETITION
           a back reference (see next section)
           a parenthesized subpattern (unless it is an assertion)
-        The general repetition quantifier specifies a minimum and maximum  num-
+        The  general repetition quantifier specifies a minimum and maximum num-
-        ber  of  permitted matches, by giving the two numbers in curly brackets
+        ber of permitted matches, by giving the two numbers in  curly  brackets
-        (braces), separated by a comma. The numbers must be  less  than  65536,
+        (braces),  separated  by  a comma. The numbers must be less than 65536,
         and the first must be less than or equal to the second. For example:
           z{2,4}
-        matches  "zz",  "zzz",  or  "zzzz". A closing brace on its own is not a
+        matches "zz", "zzz", or "zzzz". A closing brace on its  own  is  not  a
-        special character. If the second number is omitted, but  the  comma  is
+        special  character.  If  the second number is omitted, but the comma is
-        present,  there  is  no upper limit; if the second number and the comma
+        present, there is no upper limit; if the second number  and  the  comma
-        are both omitted, the quantifier specifies an exact number of  required
+        are  both omitted, the quantifier specifies an exact number of required
         matches. Thus
           [aeiou]{3,}
-Line 3708 
 REPETITION
+Line 3759 
 REPETITION
           \d{8}
-        matches  exactly  8  digits. An opening curly bracket that appears in a
+        matches exactly 8 digits. An opening curly bracket that  appears  in  a
-        position where a quantifier is not allowed, or one that does not  match
+        position  where a quantifier is not allowed, or one that does not match
-        the  syntax of a quantifier, is taken as a literal character. For exam-
+        the syntax of a quantifier, is taken as a literal character. For  exam-
         ple, {,6} is not a quantifier, but a literal string of four characters.
-        In  UTF-8  mode,  quantifiers  apply to UTF-8 characters rather than to
+        In UTF-8 mode, quantifiers apply to UTF-8  characters  rather  than  to
         individual bytes. Thus, for example, \x{100}{2} matches two UTF-8 char-
         acters, each of which is represented by a two-byte sequence. Similarly,
         when Unicode property support is available, \X{3} matches three Unicode
-        extended  sequences,  each of which may be several bytes long (and they
+        extended sequences, each of which may be several bytes long  (and  they
         may be of different lengths).
         The quantifier {0} is permitted, causing the expression to behave as if
         the previous item and the quantifier were not present.
-        For  convenience, the three most common quantifiers have single-charac-
+        For convenience, the three most common quantifiers have  single-charac-
         ter abbreviations:
           *    is equivalent to {0,}
           +    is equivalent to {1,}
           ?    is equivalent to {0,1}
-        It is possible to construct infinite loops by  following  a  subpattern
+        It  is  possible  to construct infinite loops by following a subpattern
         that can match no characters with a quantifier that has no upper limit,
         for example:
           (a?)*
         Earlier versions of Perl and PCRE used to give an error at compile time
-        for  such  patterns. However, because there are cases where this can be
+        for such patterns. However, because there are cases where this  can  be
-        useful, such patterns are now accepted, but if any  repetition  of  the
+        useful,  such  patterns  are now accepted, but if any repetition of the
-        subpattern  does in fact match no characters, the loop is forcibly bro-
+        subpattern does in fact match no characters, the loop is forcibly  bro-
         ken.
-        By default, the quantifiers are "greedy", that is, they match  as  much
+        By  default,  the quantifiers are "greedy", that is, they match as much
-        as  possible  (up  to  the  maximum number of permitted times), without
+        as possible (up to the maximum  number  of  permitted  times),  without
-        causing the rest of the pattern to fail. The classic example  of  where
+        causing  the  rest of the pattern to fail. The classic example of where
         this gives problems is in trying to match comments in C programs. These
-        appear between /* and */ and within the comment,  individual  *  and  /
+        appear  between  /*  and  */ and within the comment, individual * and /
-        characters  may  appear. An attempt to match C comments by applying the
+        characters may appear. An attempt to match C comments by  applying  the
         pattern
           /\*.*\*/
-Line 3756 
 REPETITION
+Line 3807 
 REPETITION
           /* first comment */  not comment  /* second comment */
-        fails, because it matches the entire string owing to the greediness  of
+        fails,  because it matches the entire string owing to the greediness of
         the .*  item.
-        However,  if  a quantifier is followed by a question mark, it ceases to
+        However, if a quantifier is followed by a question mark, it  ceases  to
         be greedy, and instead matches the minimum number of times possible, so
         the pattern
           /\*.*?\*/
-        does  the  right  thing with the C comments. The meaning of the various
+        does the right thing with the C comments. The meaning  of  the  various
-        quantifiers is not otherwise changed,  just  the  preferred  number  of
+        quantifiers  is  not  otherwise  changed,  just the preferred number of
-        matches.   Do  not  confuse this use of question mark with its use as a
+        matches.  Do not confuse this use of question mark with its  use  as  a
-        quantifier in its own right. Because it has two uses, it can  sometimes
+        quantifier  in its own right. Because it has two uses, it can sometimes
         appear doubled, as in
           \d??\d
-Line 3776 
 REPETITION
+Line 3827 
 REPETITION
         which matches one digit by preference, but can match two if that is the
         only way the rest of the pattern matches.
-        If the PCRE_UNGREEDY option is set (an option that is not available  in
+        If  the PCRE_UNGREEDY option is set (an option that is not available in
-        Perl),  the  quantifiers are not greedy by default, but individual ones
+        Perl), the quantifiers are not greedy by default, but  individual  ones
-        can be made greedy by following them with a  question  mark.  In  other
+        can  be  made  greedy  by following them with a question mark. In other
         words, it inverts the default behaviour.
-        When  a  parenthesized  subpattern  is quantified with a minimum repeat
+        When a parenthesized subpattern is quantified  with  a  minimum  repeat
-        count that is greater than 1 or with a limited maximum, more memory  is
+        count  that is greater than 1 or with a limited maximum, more memory is
-        required  for  the  compiled  pattern, in proportion to the size of the
+        required for the compiled pattern, in proportion to  the  size  of  the
         minimum or maximum.
         If a pattern starts with .* or .{0,} and the PCRE_DOTALL option (equiv-
-        alent  to  Perl's  /s) is set, thus allowing the dot to match newlines,
+        alent to Perl's /s) is set, thus allowing the dot  to  match  newlines,
-        the pattern is implicitly anchored, because whatever  follows  will  be
+        the  pattern  is  implicitly anchored, because whatever follows will be
-        tried  against every character position in the subject string, so there
+        tried against every character position in the subject string, so  there
-        is no point in retrying the overall match at  any  position  after  the
+        is  no  point  in  retrying the overall match at any position after the
-        first.  PCRE  normally treats such a pattern as though it were preceded
+        first. PCRE normally treats such a pattern as though it  were  preceded
         by \A.
-        In cases where it is known that the subject  string  contains  no  new-
+        In  cases  where  it  is known that the subject string contains no new-
-        lines,  it  is  worth setting PCRE_DOTALL in order to obtain this opti-
+        lines, it is worth setting PCRE_DOTALL in order to  obtain  this  opti-
         mization, or alternatively using ^ to indicate anchoring explicitly.
-        However, there is one situation where the optimization cannot be  used.
+        However,  there is one situation where the optimization cannot be used.
-        When  .*   is  inside  capturing  parentheses that are the subject of a
+        When .*  is inside capturing parentheses that  are  the  subject  of  a
-        backreference elsewhere in the pattern, a match at the start  may  fail
+        backreference  elsewhere  in the pattern, a match at the start may fail
         where a later one succeeds. Consider, for example:
           (.*)abc\1
-        If  the subject is "xyz123abc123" the match point is the fourth charac-
+        If the subject is "xyz123abc123" the match point is the fourth  charac-
         ter. For this reason, such a pattern is not implicitly anchored.
         When a capturing subpattern is repeated, the value captured is the sub-
-Line 3814 
 REPETITION
+Line 3865 
 REPETITION
           (tweedle[dume]{3}\s*)+
         has matched "tweedledum tweedledee" the value of the captured substring
-        is "tweedledee". However, if there are  nested  capturing  subpatterns,
+        is  "tweedledee".  However,  if there are nested capturing subpatterns,
-        the  corresponding captured values may have been set in previous itera-
+        the corresponding captured values may have been set in previous  itera-
         tions. For example, after
           /(a|(b))+/
-Line 3825 
 REPETITION
+Line 3876 
 REPETITION
  ATOMIC GROUPING AND POSSESSIVE QUANTIFIERS
-        With both maximizing ("greedy") and minimizing ("ungreedy"  or  "lazy")
+        With  both  maximizing ("greedy") and minimizing ("ungreedy" or "lazy")
-        repetition,  failure  of what follows normally causes the repeated item
+        repetition, failure of what follows normally causes the  repeated  item
-        to be re-evaluated to see if a different number of repeats  allows  the
+        to  be  re-evaluated to see if a different number of repeats allows the
-        rest  of  the pattern to match. Sometimes it is useful to prevent this,
+        rest of the pattern to match. Sometimes it is useful to  prevent  this,
-        either to change the nature of the match, or to cause it  fail  earlier
+        either  to  change the nature of the match, or to cause it fail earlier
-        than  it otherwise might, when the author of the pattern knows there is
+        than it otherwise might, when the author of the pattern knows there  is
         no point in carrying on.
-        Consider, for example, the pattern \d+foo when applied to  the  subject
+        Consider,  for  example, the pattern \d+foo when applied to the subject
         line
 bar
         After matching all 6 digits and then failing to match "foo", the normal
-        action of the matcher is to try again with only 5 digits  matching  the
+        action  of  the matcher is to try again with only 5 digits matching the
-        \d+  item,  and  then  with  4,  and  so on, before ultimately failing.
+        \d+ item, and then with  4,  and  so  on,  before  ultimately  failing.
-        "Atomic grouping" (a term taken from Jeffrey  Friedl's  book)  provides
+        "Atomic  grouping"  (a  term taken from Jeffrey Friedl's book) provides
-        the  means for specifying that once a subpattern has matched, it is not
+        the means for specifying that once a subpattern has matched, it is  not
         to be re-evaluated in this way.
-        If we use atomic grouping for the previous example, the  matcher  gives
+        If  we  use atomic grouping for the previous example, the matcher gives
-        up  immediately  on failing to match "foo" the first time. The notation
+        up immediately on failing to match "foo" the first time.  The  notation
         is a kind of special parenthesis, starting with (?> as in this example:
           (?>\d+)foo
-        This  kind  of  parenthesis "locks up" the  part of the pattern it con-
+        This kind of parenthesis "locks up" the  part of the  pattern  it  con-
-        tains once it has matched, and a failure further into  the  pattern  is
+        tains  once  it  has matched, and a failure further into the pattern is
-        prevented  from  backtracking into it. Backtracking past it to previous
+        prevented from backtracking into it. Backtracking past it  to  previous
         items, however, works as normal.
-        An alternative description is that a subpattern of  this  type  matches
+        An  alternative  description  is that a subpattern of this type matches
-        the  string  of  characters  that an identical standalone pattern would
+        the string of characters that an  identical  standalone  pattern  would
         match, if anchored at the current point in the subject string.
         Atomic grouping subpatterns are not capturing subpatterns. Simple cases
         such as the above example can be thought of as a maximizing repeat that
-        must swallow everything it can. So, while both \d+ and  \d+?  are  pre-
+        must  swallow  everything  it can. So, while both \d+ and \d+? are pre-
-        pared  to  adjust  the number of digits they match in order to make the
+        pared to adjust the number of digits they match in order  to  make  the
         rest of the pattern match, (?>\d+) can only match an entire sequence of
         digits.
-        Atomic  groups in general can of course contain arbitrarily complicated
+        Atomic groups in general can of course contain arbitrarily  complicated
-        subpatterns, and can be nested. However, when  the  subpattern  for  an
+        subpatterns,  and  can  be  nested. However, when the subpattern for an
         atomic group is just a single repeated item, as in the example above, a
-        simpler notation, called a "possessive quantifier" can  be  used.  This
+        simpler  notation,  called  a "possessive quantifier" can be used. This
-        consists  of  an  additional  + character following a quantifier. Using
+        consists of an additional + character  following  a  quantifier.  Using
         this notation, the previous example can be rewritten as
           \d++foo
+        Note that a possessive quantifier can be used with an entire group, for
+        example:
+          (abc|xyz){2,3}+
         Possessive  quantifiers  are  always  greedy;  the   setting   of   the
         PCRE_UNGREEDY option is ignored. They are a convenient notation for the
         simpler forms of atomic group. However, there is no difference  in  the
-Line 3948 
 BACK REFERENCES
+Line 4004 
 BACK REFERENCES
         Another way of avoiding the ambiguity inherent in  the  use  of  digits
         following a backslash is to use the \g escape sequence, which is a fea-
-        ture introduced in Perl 5.10. This escape must be followed by  a  posi-
+        ture introduced in Perl 5.10.  This  escape  must  be  followed  by  an
-        tive  or  a negative number, optionally enclosed in braces. These exam-
+        unsigned  number  or  a negative number, optionally enclosed in braces.
-        ples are all identical:
+        These examples are all identical:
           (ring), \1
           (ring), \g1
           (ring), \g{1}
-        A positive number specifies an absolute reference without the ambiguity
+        An unsigned number specifies an absolute reference without the  ambigu-
-        that  is  present  in  the older syntax. It is also useful when literal
+        ity that is present in the older syntax. It is also useful when literal
         digits follow the reference. A negative number is a relative reference.
         Consider this example:
-Line 4529 
 CALLOUTS
+Line 4585 
 CALLOUTS
         is given in the pcrecallout documentation.
+ BACTRACKING CONTROL
+        Perl  5.10 introduced a number of "Special Backtracking Control Verbs",
+        which are described in the Perl documentation as "experimental and sub-
+        ject  to  change or removal in a future version of Perl". It goes on to
+        say: "Their usage in production code should be noted to avoid  problems
+        during upgrades." The same remarks apply to the PCRE features described
+        in this section.
+        Since these verbs are specifically related to backtracking, they can be
+        used  only  when  the pattern is to be matched using pcre_exec(), which
+        uses a backtracking algorithm. They cause an error  if  encountered  by
+        pcre_dfa_exec().
+        The  new verbs make use of what was previously invalid syntax: an open-
+        ing parenthesis followed by an asterisk. In Perl, they are generally of
+        the form (*VERB:ARG) but PCRE does not support the use of arguments, so
+        its general form is just (*VERB). Any number of these verbs  may  occur
+        in a pattern. There are two kinds:
+    Verbs that act immediately
+        The following verbs act as soon as they are encountered:
+           (*ACCEPT)
+        This  verb causes the match to end successfully, skipping the remainder
+        of the pattern. When inside a recursion, only the innermost pattern  is
+        ended  immediately.  PCRE  differs  from  Perl  in  what happens if the
+        (*ACCEPT) is inside capturing parentheses. In Perl, the data so far  is
+        captured: in PCRE no data is captured. For example:
+          A(A|B(*ACCEPT)|C)D
+        This  matches  "AB", "AAD", or "ACD", but when it matches "AB", no data
+        is captured.
+          (*FAIL) or (*F)
+        This verb causes the match to fail, forcing backtracking to  occur.  It
+        is  equivalent to (?!) but easier to read. The Perl documentation notes
+        that it is probably useful only when combined  with  (?{})  or  (??{}).
+        Those  are,  of course, Perl features that are not present in PCRE. The
+        nearest equivalent is the callout feature, as for example in this  pat-
+        tern:
+          a+(?C)(*FAIL)
+        A  match  with the string "aaaa" always fails, but the callout is taken
+        before each backtrack happens (in this example, 10 times).
+    Verbs that act after backtracking
+        The following verbs do nothing when they are encountered. Matching con-
+        tinues  with what follows, but if there is no subsequent match, a fail-
+        ure is forced.  The verbs  differ  in  exactly  what  kind  of  failure
+        occurs.
+          (*COMMIT)
+        This  verb  causes  the whole match to fail outright if the rest of the
+        pattern does not match. Even if the pattern is unanchored,  no  further
+        attempts  to find a match by advancing the start point take place. Once
+        (*COMMIT) has been passed, pcre_exec() is committed to finding a  match
+        at the current starting point, or not at all. For example:
+          a+(*COMMIT)b
+        This  matches  "xxaab" but not "aacaab". It can be thought of as a kind
+        of dynamic anchor, or "I've started, so I must finish."
+          (*PRUNE)
+        This verb causes the match to fail at the current position if the  rest
+        of the pattern does not match. If the pattern is unanchored, the normal
+        "bumpalong" advance to the next starting character then happens.  Back-
+        tracking  can  occur as usual to the left of (*PRUNE), or when matching
+        to the right of (*PRUNE), but if there is no match to the right,  back-
+        tracking  cannot  cross (*PRUNE).  In simple cases, the use of (*PRUNE)
+        is just an alternative to an atomic group or possessive quantifier, but
+        there  are  some uses of (*PRUNE) that cannot be expressed in any other
+        way.
+          (*SKIP)
+        This verb is like (*PRUNE), except that if the pattern  is  unanchored,
+        the  "bumpalong" advance is not to the next character, but to the posi-
+        tion in the subject where (*SKIP) was  encountered.  (*SKIP)  signifies
+        that  whatever  text  was  matched leading up to it cannot be part of a
+        successful match. Consider:
+          a+(*SKIP)b
+        If the subject is "aaaac...",  after  the  first  match  attempt  fails
+        (starting  at  the  first  character in the string), the starting point
+        skips on to start the next attempt at "c". Note that a possessive quan-
+        tifer  does not have the same effect in this example; although it would
+        suppress backtracking  during  the  first  match  attempt,  the  second
+        attempt  would  start at the second character instead of skipping on to
+        "c".
+          (*THEN)
+        This verb causes a skip to the next alternation if the rest of the pat-
+        tern does not match. That is, it cancels pending backtracking, but only
+        within the current alternation. Its name  comes  from  the  observation
+        that it can be used for a pattern-based if-then-else block:
+          ( COND1 (*THEN) FOO | COND2 (*THEN) BAR | COND3 (*THEN) BAZ ) ...
+        If  the COND1 pattern matches, FOO is tried (and possibly further items
+        after the end of the group if FOO succeeds);  on  failure  the  matcher
+        skips  to  the second alternative and tries COND2, without backtracking
+        into COND1. If (*THEN) is used outside  of  any  alternation,  it  acts
+        exactly like (*PRUNE).
  SEE ALSO
         pcreapi(3), pcrecallout(3), pcrematching(3), pcre(3).
-Line 4543 
 AUTHOR
+Line 4716 
 AUTHOR
  REVISION
-        Last updated: 19 June 2007
+        Last updated: 09 August 2007
+        Copyright (c) 1997-2007 University of Cambridge.
+ ------------------------------------------------------------------------------
+ PCRESYNTAX(3)                                                    PCRESYNTAX(3)
+ NAME
+        PCRE - Perl-compatible regular expressions
+ PCRE REGULAR EXPRESSION SYNTAX SUMMARY
+        The  full syntax and semantics of the regular expressions that are sup-
+        ported by PCRE are described in  the  pcrepattern  documentation.  This
+        document contains just a quick-reference summary of the syntax.
+ QUOTING
+          \x         where x is non-alphanumeric is a literal x
+          \Q...\E    treat enclosed characters as literal
+ CHARACTERS
+          \a         alarm, that is, the BEL character (hex 07)
+          \cx        "control-x", where x is any character
+          \e         escape (hex 1B)
+          \f         formfeed (hex 0C)
+          \n         newline (hex 0A)
+          \r         carriage return (hex 0D)
+          \t         tab (hex 09)
+          \ddd       character with octal code ddd, or backreference
+          \xhh       character with hex code hh
+          \x{hhh..}  character with hex code hhh..
+ CHARACTER TYPES
+          .          any character except newline;
+                       in dotall mode, any character whatsoever
+          \C         one byte, even in UTF-8 mode (best avoided)
+          \d         a decimal digit
+          \D         a character that is not a decimal digit
+          \h         a horizontal whitespace character
+          \H         a character that is not a horizontal whitespace character
+          \p{xx}     a character with the xx property
+          \P{xx}     a character without the xx property
+          \R         a newline sequence
+          \s         a whitespace character
+          \S         a character that is not a whitespace character
+          \v         a vertical whitespace character
+          \V         a character that is not a vertical whitespace character
+          \w         a "word" character
+          \W         a "non-word" character
+          \X         an extended Unicode sequence
+        In PCRE, \d, \D, \s, \S, \w, and \W recognize only ASCII characters.
+ GENERAL CATEGORY PROPERTY CODES FOR \p and \P
+          C          Other
+          Cc         Control
+          Cf         Format
+          Cn         Unassigned
+          Co         Private use
+          Cs         Surrogate
+          L          Letter
+          Ll         Lower case letter
+          Lm         Modifier letter
+          Lo         Other letter
+          Lt         Title case letter
+          Lu         Upper case letter
+          L&         Ll, Lu, or Lt
+          M          Mark
+          Mc         Spacing mark
+          Me         Enclosing mark
+          Mn         Non-spacing mark
+          N          Number
+          Nd         Decimal number
+          Nl         Letter number
+          No         Other number
+          P          Punctuation
+          Pc         Connector punctuation
+          Pd         Dash punctuation
+          Pe         Close punctuation
+          Pf         Final punctuation
+          Pi         Initial punctuation
+          Po         Other punctuation
+          Ps         Open punctuation
+          S          Symbol
+          Sc         Currency symbol
+          Sk         Modifier symbol
+          Sm         Mathematical symbol
+          So         Other symbol
+          Z          Separator
+          Zl         Line separator
+          Zp         Paragraph separator
+          Zs         Space separator
+ SCRIPT NAMES FOR \p AND \P
+        Arabic,  Armenian,  Balinese,  Bengali,  Bopomofo,  Braille,  Buginese,
+        Buhid,  Canadian_Aboriginal,  Cherokee,  Common,   Coptic,   Cuneiform,
+        Cypriot, Cyrillic, Deseret, Devanagari, Ethiopic, Georgian, Glagolitic,
+        Gothic, Greek, Gujarati, Gurmukhi, Han, Hangul, Hanunoo, Hebrew,  Hira-
+        gana,  Inherited,  Kannada,  Katakana,  Kharoshthi,  Khmer, Lao, Latin,
+        Limbu,  Linear_B,  Malayalam,  Mongolian,  Myanmar,  New_Tai_Lue,  Nko,
+        Ogham,  Old_Italic,  Old_Persian, Oriya, Osmanya, Phags_Pa, Phoenician,
+        Runic,  Shavian,  Sinhala,  Syloti_Nagri,  Syriac,  Tagalog,  Tagbanwa,
+        Tai_Le, Tamil, Telugu, Thaana, Thai, Tibetan, Tifinagh, Ugaritic, Yi.
+ CHARACTER CLASSES
+          [...]       positive character class
+          [^...]      negative character class
+          [x-y]       range (can be used for hex characters)
+          [[:xxx:]]   positive POSIX named set
+          [[^:xxx:]]  negative POSIX named set
+          alnum       alphanumeric
+          alpha       alphabetic
+          ascii       0-127
+          blank       space or tab
+          cntrl       control character
+          digit       decimal digit
+          graph       printing, excluding space
+          lower       lower case letter
+          print       printing, including space
+          punct       printing, excluding alphanumeric
+          space       whitespace
+          upper       upper case letter
+          word        same as \w
+          xdigit      hexadecimal digit
+        In PCRE, POSIX character set names recognize only ASCII characters. You
+        can use \Q...\E inside a character class.
+ QUANTIFIERS
+          ?           0 or 1, greedy
+          ?+          0 or 1, possessive
+          ??          0 or 1, lazy
+          *           0 or more, greedy
+          *+          0 or more, possessive
+          *?          0 or more, lazy
+          +           1 or more, greedy
+          ++          1 or more, possessive
+          +?          1 or more, lazy
+          {n}         exactly n
+          {n,m}       at least n, no more than m, greedy
+          {n,m}+      at least n, no more than m, possessive
+          {n,m}?      at least n, no more than m, lazy
+          {n,}        n or more, greedy
+          {n,}+       n or more, possessive
+          {n,}?       n or more, lazy
+ ANCHORS AND SIMPLE ASSERTIONS
+          \b          word boundary
+          \B          not a word boundary
+          ^           start of subject
+                       also after internal newline in multiline mode
+          \A          start of subject
+          $           end of subject
+                       also before newline at end of subject
+                       also before internal newline in multiline mode
+          \Z          end of subject
+                       also before newline at end of subject
+          \z          end of subject
+          \G          first matching position in subject
+ MATCH POINT RESET
+          \K          reset start of match
+ ALTERNATION
+          expr|expr|expr...
+ CAPTURING
+          (...)          capturing group
+          (?<name>...)   named capturing group (Perl)
+          (?'name'...)   named capturing group (Perl)
+          (?P<name>...)  named capturing group (Python)
+          (?:...)        non-capturing group
+          (?|...)        non-capturing group; reset group numbers for
+                          capturing groups in each alternative
+ ATOMIC GROUPS
+          (?>...)        atomic, non-capturing group
+ COMMENT
+          (?#....)       comment (not nestable)
+ OPTION SETTING
+          (?i)           caseless
+          (?J)           allow duplicate names
+          (?m)           multiline
+          (?s)           single line (dotall)
+          (?U)           default ungreedy (lazy)
+          (?x)           extended (ignore white space)
+          (?-...)        unset option(s)
+ LOOKAHEAD AND LOOKBEHIND ASSERTIONS
+          (?=...)        positive look ahead
+          (?!...)        negative look ahead
+          (?<=...)       positive look behind
+          (?<!...)       negative look behind
+        Each top-level branch of a look behind must be of a fixed length.
+ BACKREFERENCES
+          \n             reference by number (can be ambiguous)
+          \gn            reference by number
+          \g{n}          reference by number
+          \g{-n}         relative reference by number
+          \k<name>       reference by name (Perl)
+          \k'name'       reference by name (Perl)
+          \g{name}       reference by name (Perl)
+          \k{name}       reference by name (.NET)
+          (?P=name)      reference by name (Python)
+ SUBROUTINE REFERENCES (POSSIBLY RECURSIVE)
+          (?R)           recurse whole pattern
+          (?n)           call subpattern by absolute number
+          (?+n)          call subpattern by relative number
+          (?-n)          call subpattern by relative number
+          (?&name)       call subpattern by name (Perl)
+          (?P>name)      call subpattern by name (Python)
+ CONDITIONAL PATTERNS
+          (?(condition)yes-pattern)
+          (?(condition)yes-pattern|no-pattern)
+          (?(n)...       absolute reference condition
+          (?(+n)...      relative reference condition
+          (?(-n)...      relative reference condition
+          (?(<name>)...  named reference condition (Perl)
+          (?('name')...  named reference condition (Perl)
+          (?(name)...    named reference condition (PCRE)
+          (?(R)...       overall recursion condition
+          (?(Rn)...      specific group recursion condition
+          (?(R&name)...  specific recursion condition
+          (?(DEFINE)...  define subpattern for reference
+          (?(assert)...  assertion condition
+ BACKTRACKING CONTROL
+        The following act immediately they are reached:
+          (*ACCEPT)      force successful match
+          (*FAIL)        force backtrack; synonym (*F)
+        The following act only when a subsequent match failure causes  a  back-
+        track to reach them. They all force a match failure, but they differ in
+        what happens afterwards. Those that advance the start-of-match point do
+        so only if the pattern is not anchored.
+          (*COMMIT)      overall failure, no advance of starting point
+          (*PRUNE)       advance to next starting character
+          (*SKIP)        advance start to current matching position
+          (*THEN)        local failure, backtrack to next alternation
+ CALLOUTS
+          (?C)      callout
+          (?Cn)     callout with data n
+ SEE ALSO
+        pcrepattern(3), pcreapi(3), pcrecallout(3), pcrematching(3), pcre(3).
+ AUTHOR
+        Philip Hazel
+        University Computing Service
+        Cambridge CB2 3QH, England.
+ REVISION
+        Last updated: 08 August 2007
         Copyright (c) 1997-2007 University of Cambridge.
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