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

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-revision 155 by ph10,
Tue Apr 24 13:36:11 2007 UTC
+revision 292 by ph10,
Thu Dec 27 09:27:23 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.
-.  Case-insensitive  matching  applies only to characters whose values
+. However, the Perl 5.10 horizontal and vertical  whitespace  matching
-        are less than 128, unless PCRE is built with Unicode property  support.
+        escapes (\h, \H, \v, and \V) do match all the appropriate Unicode char-
-        Even  when  Unicode  property support is available, PCRE still uses its
+        acters.
-        own character tables when checking the case of  low-valued  characters,
-        so  as not to degrade performance.  The Unicode property information is
+. Case-insensitive matching applies only to  characters  whose  values
+        are  less than 128, unless PCRE is built with Unicode property support.
+        Even when Unicode property support is available, PCRE  still  uses  its
+        own  character  tables when checking the case of low-valued characters,
+        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 215 
 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: 18 April 2007
+        Last updated: 09 August 2007
         Copyright (c) 1997-2007 University of Cambridge.
  ------------------------------------------------------------------------------
-Line 237 
 NAME
+Line 271 
 NAME
  PCRE BUILD-TIME OPTIONS
         This  document  describes  the  optional  features  of PCRE that can be
-        selected when the library is compiled. They are all selected, or  dese-
+        selected when the library is compiled. It assumes use of the  configure
-        lected, by providing options to the configure script that is run before
+        script,  where the optional features are selected or deselected by pro-
-        the make command. The complete list of  options  for  configure  (which
+        viding options to configure before running the make  command.  However,
-        includes  the  standard  ones such as the selection of the installation
+        the  same  options  can be selected in both Unix-like and non-Unix-like
-        directory) can be obtained by running
+        environments using the GUI facility of  CMakeSetup  if  you  are  using
+        CMake instead of configure to build PCRE.
+        The complete list of options for configure (which includes the standard
+        ones such as the  selection  of  the  installation  directory)  can  be
+        obtained by running
           ./configure --help
-        The following sections include  descriptions  of  options  whose  names
+        The  following  sections  include  descriptions  of options whose names
         begin with --enable or --disable. These settings specify changes to the
-        defaults for the configure command. Because of the way  that  configure
+        defaults  for  the configure command. Because of the way that configure
-        works,  --enable  and --disable always come in pairs, so the complemen-
+        works, --enable and --disable always come in pairs, so  the  complemen-
-        tary option always exists as well, but as it specifies the default,  it
+        tary  option always exists as well, but as it specifies the default, it
         is not described.
-Line 270 
 UTF-8 SUPPORT
+Line 309 
 UTF-8 SUPPORT
           --enable-utf8
-        to  the  configure  command.  Of  itself, this does not make PCRE treat
+        to the configure command. Of itself, this  does  not  make  PCRE  treat
-        strings as UTF-8. As well as compiling PCRE with this option, you  also
+        strings  as UTF-8. As well as compiling PCRE with this option, you also
-        have  have to set the PCRE_UTF8 option when you call the pcre_compile()
+        have have to set the PCRE_UTF8 option when you call the  pcre_compile()
         function.
  UNICODE CHARACTER PROPERTY SUPPORT
-        UTF-8 support allows PCRE to process character values greater than  255
+        UTF-8  support allows PCRE to process character values greater than 255
-        in  the  strings that it handles. On its own, however, it does not pro-
+        in the strings that it handles. On its own, however, it does  not  pro-
         vide any facilities for accessing the properties of such characters. If
-        you  want  to  be able to use the pattern escapes \P, \p, and \X, which
+        you want to be able to use the pattern escapes \P, \p,  and  \X,  which
         refer to Unicode character properties, you must add
           --enable-unicode-properties
-        to the configure command. This implies UTF-8 support, even if you  have
+        to  the configure command. This implies UTF-8 support, even if you have
         not explicitly requested it.
-        Including  Unicode  property  support  adds around 30K of tables to the
+        Including Unicode property support adds around 30K  of  tables  to  the
-        PCRE library. Only the general category properties such as  Lu  and  Nd
+        PCRE  library.  Only  the general category properties such as Lu and Nd
         are supported. Details are given in the pcrepattern documentation.
  CODE VALUE OF NEWLINE
-        By  default,  PCRE interprets character 10 (linefeed, LF) as indicating
+        By default, PCRE interprets character 10 (linefeed, LF)  as  indicating
-        the end of a line. This is the normal newline  character  on  Unix-like
+        the  end  of  a line. This is the normal newline character on Unix-like
         systems. You can compile PCRE to use character 13 (carriage return, CR)
         instead, by adding
           --enable-newline-is-cr
-        to the  configure  command.  There  is  also  a  --enable-newline-is-lf
+        to  the  configure  command.  There  is  also  a --enable-newline-is-lf
         option, which explicitly specifies linefeed as the newline character.
         Alternatively, you can specify that line endings are to be indicated by
-Line 315 
 CODE VALUE OF NEWLINE
+Line 354 
 CODE VALUE OF NEWLINE
           --enable-newline-is-anycrlf
-        which causes PCRE to recognize any of the three sequences  CR,  LF,  or
+        which  causes  PCRE  to recognize any of the three sequences CR, LF, or
         CRLF as indicating a line ending. Finally, a fifth option, specified by
           --enable-newline-is-any
         causes PCRE to recognize any Unicode newline sequence.
-        Whatever line ending convention is selected when PCRE is built  can  be
+        Whatever  line  ending convention is selected when PCRE is built can be
-        overridden  when  the library functions are called. At build time it is
+        overridden when the library functions are called. At build time  it  is
         conventional to use the standard for your operating system.
+ WHAT \R MATCHES
+        By  default,  the  sequence \R in a pattern matches any Unicode newline
+        sequence, whatever has been selected as the line  ending  sequence.  If
+        you specify
+          --enable-bsr-anycrlf
+        the  default  is changed so that \R matches only CR, LF, or CRLF. What-
+        ever is selected when PCRE is built can be overridden when the  library
+        functions are called.
  BUILDING SHARED AND STATIC LIBRARIES
-        The PCRE building process uses libtool to build both shared and  static
+        The  PCRE building process uses libtool to build both shared and static
-        Unix  libraries by default. You can suppress one of these by adding one
+        Unix libraries by default. You can suppress one of these by adding  one
         of
           --disable-shared
-Line 342 
 BUILDING SHARED AND STATIC LIBRARIES
+Line 394 
 BUILDING SHARED AND STATIC LIBRARIES
  POSIX MALLOC USAGE
         When PCRE is called through the POSIX interface (see the pcreposix doc-
-        umentation),  additional  working  storage  is required for holding the
+        umentation), additional working storage is  required  for  holding  the
-        pointers to capturing substrings, because PCRE requires three  integers
+        pointers  to capturing substrings, because PCRE requires three integers
-        per  substring,  whereas  the POSIX interface provides only two. If the
+        per substring, whereas the POSIX interface provides only  two.  If  the
         number of expected substrings is small, the wrapper function uses space
         on the stack, because this is faster than using malloc() for each call.
         The default threshold above which the stack is no longer used is 10; it
-Line 357 
 POSIX MALLOC USAGE
+Line 409 
 POSIX MALLOC USAGE
  HANDLING VERY LARGE PATTERNS
-        Within  a  compiled  pattern,  offset values are used to point from one
+        Within a compiled pattern, offset values are used  to  point  from  one
-        part to another (for example, from an opening parenthesis to an  alter-
+        part  to another (for example, from an opening parenthesis to an alter-
-        nation  metacharacter).  By default, two-byte values are used for these
+        nation metacharacter). By default, two-byte values are used  for  these
-        offsets, leading to a maximum size for a  compiled  pattern  of  around
+        offsets,  leading  to  a  maximum size for a compiled pattern of around
-K.  This  is sufficient to handle all but the most gigantic patterns.
+K. This is sufficient to handle all but the most  gigantic  patterns.
-        Nevertheless, some people do want to process enormous patterns,  so  it
+        Nevertheless,  some  people do want to process enormous patterns, so it
-        is  possible  to compile PCRE to use three-byte or four-byte offsets by
+        is possible to compile PCRE to use three-byte or four-byte  offsets  by
         adding a setting such as
           --with-link-size=3
-        to the configure command. The value given must be 2,  3,  or  4.  Using
+        to  the  configure  command.  The value given must be 2, 3, or 4. Using
-        longer  offsets slows down the operation of PCRE because it has to load
+        longer offsets slows down the operation of PCRE because it has to  load
         additional bytes when handling them.
  AVOIDING EXCESSIVE STACK USAGE
         When matching with the pcre_exec() function, PCRE implements backtrack-
-        ing  by  making recursive calls to an internal function called match().
+        ing by making recursive calls to an internal function  called  match().
-        In environments where the size of the stack is limited,  this  can  se-
+        In  environments  where  the size of the stack is limited, this can se-
-        verely  limit  PCRE's operation. (The Unix environment does not usually
+        verely limit PCRE's operation. (The Unix environment does  not  usually
         suffer from this problem, but it may sometimes be necessary to increase
-        the  maximum  stack size.  There is a discussion in the pcrestack docu-
+        the maximum stack size.  There is a discussion in the  pcrestack  docu-
-        mentation.) An alternative approach to recursion that uses memory  from
+        mentation.)  An alternative approach to recursion that uses memory from
-        the  heap  to remember data, instead of using recursive function calls,
+        the heap to remember data, instead of using recursive  function  calls,
-        has been implemented to work round the problem of limited  stack  size.
+        has  been  implemented to work round the problem of limited stack size.
         If you want to build a version of PCRE that works this way, add
           --disable-stack-for-recursion
-        to  the  configure  command. With this configuration, PCRE will use the
+        to the configure command. With this configuration, PCRE  will  use  the
-        pcre_stack_malloc and pcre_stack_free variables to call memory  manage-
+        pcre_stack_malloc  and pcre_stack_free variables to call memory manage-
-        ment  functions.  Separate  functions are provided because the usage is
+        ment functions. By default these point to malloc() and free(), but  you
-        very predictable: the block sizes requested are always  the  same,  and
+        can replace the pointers so that your own functions are used.
-        the  blocks  are always freed in reverse order. A calling program might
-        be able to implement optimized functions that perform better  than  the
+        Separate  functions  are  provided  rather  than  using pcre_malloc and
-        standard  malloc()  and  free()  functions.  PCRE  runs noticeably more
+        pcre_free because the  usage  is  very  predictable:  the  block  sizes
-        slowly when built in this way. This option affects only the pcre_exec()
+        requested  are  always  the  same,  and  the blocks are always freed in
-        function; it is not relevant for the the pcre_dfa_exec() function.
+        reverse order. A calling program might be able to  implement  optimized
+        functions  that  perform  better  than  malloc()  and free(). PCRE runs
+        noticeably more slowly when built in this way. This option affects only
+        the   pcre_exec()   function;   it   is   not   relevant  for  the  the
+        pcre_dfa_exec() function.
  LIMITING PCRE RESOURCE USAGE
-        Internally,  PCRE has a function called match(), which it calls repeat-
+        Internally, PCRE has a function called match(), which it calls  repeat-
-        edly  (sometimes  recursively)  when  matching  a  pattern   with   the
+        edly   (sometimes   recursively)  when  matching  a  pattern  with  the
-        pcre_exec()  function.  By controlling the maximum number of times this
+        pcre_exec() function. By controlling the maximum number of  times  this
-        function may be called during a single matching operation, a limit  can
+        function  may be called during a single matching operation, a limit can
-        be  placed  on  the resources used by a single call to pcre_exec(). The
+        be placed on the resources used by a single call  to  pcre_exec().  The
-        limit can be changed at run time, as described in the pcreapi  documen-
+        limit  can be changed at run time, as described in the pcreapi documen-
-        tation.  The default is 10 million, but this can be changed by adding a
+        tation. The default is 10 million, but this can be changed by adding  a
         setting such as
           --with-match-limit=500000
-        to  the  configure  command.  This  setting  has  no  effect   on   the
+        to   the   configure  command.  This  setting  has  no  effect  on  the
         pcre_dfa_exec() matching function.
-        In  some  environments  it is desirable to limit the depth of recursive
+        In some environments it is desirable to limit the  depth  of  recursive
         calls of match() more strictly than the total number of calls, in order
-        to  restrict  the maximum amount of stack (or heap, if --disable-stack-
+        to restrict the maximum amount of stack (or heap,  if  --disable-stack-
         for-recursion is specified) that is used. A second limit controls this;
-        it  defaults  to  the  value  that is set for --with-match-limit, which
+        it defaults to the value that  is  set  for  --with-match-limit,  which
-        imposes no additional constraints. However, you can set a  lower  limit
+        imposes  no  additional constraints. However, you can set a lower limit
         by adding, for example,
           --with-match-limit-recursion=10000
-        to  the  configure  command.  This  value can also be overridden at run
+        to the configure command. This value can  also  be  overridden  at  run
         time.
  CREATING CHARACTER TABLES AT BUILD TIME
-        PCRE uses fixed tables for processing characters whose code values  are
+        PCRE  uses fixed tables for processing characters whose code values are
-        less  than 256. By default, PCRE is built with a set of tables that are
+        less than 256. By default, PCRE is built with a set of tables that  are
-        distributed in the file pcre_chartables.c.dist. These  tables  are  for
+        distributed  in  the  file pcre_chartables.c.dist. These tables are for
         ASCII codes only. If you add
           --enable-rebuild-chartables
-        to  the  configure  command, the distributed tables are no longer used.
+        to the configure command, the distributed tables are  no  longer  used.
-        Instead, a program called dftables is compiled and  run.  This  outputs
+        Instead,  a  program  called dftables is compiled and run. This outputs
         the source for new set of tables, created in the default locale of your
         C runtime system. (This method of replacing the tables does not work if
-        you  are cross compiling, because dftables is run on the local host. If
+        you are cross compiling, because dftables is run on the local host.  If
-        you need to create alternative tables when cross  compiling,  you  will
+        you  need  to  create alternative tables when cross compiling, you will
         have to do so "by hand".)
  USING EBCDIC CODE
-        PCRE  assumes  by  default that it will run in an environment where the
+        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).
+        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).
+ PCREGREP OPTIONS FOR COMPRESSED FILE SUPPORT
+        By default, pcregrep reads all files as plain text. You can build it so
+        that it recognizes files whose names end in .gz or .bz2, and reads them
+        with libz or libbz2, respectively, by adding one or both of
+          --enable-pcregrep-libz
+          --enable-pcregrep-libbz2
+        to the configure command. These options naturally require that the rel-
+        evant libraries are installed on your system. Configuration  will  fail
+        if they are not.
+ PCRETEST OPTION FOR LIBREADLINE SUPPORT
+        If you add
+          --enable-pcretest-libreadline
+        to  the  configure  command,  pcretest  is  linked with the libreadline
+        library, and when its input is from a terminal, it reads it  using  the
+        readline() function. This provides line-editing and history facilities.
+        Note that libreadline is GPL-licenced, so if you distribute a binary of
+        pcretest linked in this way, there may be licensing issues.
  SEE ALSO
-Line 474 
 AUTHOR
+Line 558 
 AUTHOR
  REVISION
-        Last updated: 16 April 2007
+        Last updated: 18 December 2007
         Copyright (c) 1997-2007 University of Cambridge.
  ------------------------------------------------------------------------------
-Line 610 
 THE ALTERNATIVE MATCHING ALGORITHM
+Line 694 
 THE ALTERNATIVE MATCHING ALGORITHM
         ence  as  the  condition or test for a specific group recursion are not
         supported.
-. Callouts are supported, but the value of the  capture_top  field  is
+. Because many paths through the tree may be  active,  the  \K  escape
+        sequence, which resets the start of the match when encountered (but may
+        be on some paths and not on others), is not  supported.  It  causes  an
+        error if encountered.
+.  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-
+        single  byte, even in UTF-8 mode, is not supported because the alterna-
-        tive  algorithm  moves  through  the  subject string one character at a
+        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
-Line 664 
 AUTHOR
+Line 756 
 AUTHOR
  REVISION
-        Last updated: 06 March 2007
+        Last updated: 08 August 2007
         Copyright (c) 1997-2007 University of Cambridge.
  ------------------------------------------------------------------------------
-Line 861 
 NEWLINES
+Line 953 
 NEWLINES
         dard. When PCRE is run, the default can be overridden,  either  when  a
         pattern is compiled, or when it is matched.
+        At compile time, the newline convention can be specified by the options
+        argument of pcre_compile(), or it can be specified by special  text  at
+        the start of the pattern itself; this overrides any other settings. See
+        the pcrepattern page for details of the special character sequences.
         In the PCRE documentation the word "newline" is used to mean "the char-
-        acter or pair of characters that indicate a line break". The choice  of
+        acter  or pair of characters that indicate a line break". The choice of
-        newline  convention  affects  the  handling of the dot, circumflex, and
+        newline convention affects the handling of  the  dot,  circumflex,  and
         dollar metacharacters, the handling of #-comments in /x mode, and, when
-        CRLF  is a recognized line ending sequence, the match position advance-
+        CRLF is a recognized line ending sequence, the match position  advance-
-        ment for a non-anchored pattern. The choice of newline convention  does
+        ment for a non-anchored pattern. There is more detail about this in the
-        not affect the interpretation of the \n or \r escape sequences.
+        section on pcre_exec() options below.
+        The choice of newline convention does not affect the interpretation  of
+        the  \n  or  \r  escape  sequences, nor does it affect what \R matches,
+        which is controlled in a similar way, but by separate options.
  MULTITHREADING
-        The  PCRE  functions  can be used in multi-threading applications, with
+        The PCRE functions can be used in  multi-threading  applications,  with
         the  proviso  that  the  memory  management  functions  pointed  to  by
         pcre_malloc, pcre_free, pcre_stack_malloc, and pcre_stack_free, and the
         callout function pointed to by pcre_callout, are shared by all threads.
-        The  compiled form of a regular expression is not altered during match-
+        The compiled form of a regular expression is not altered during  match-
         ing, so the same compiled pattern can safely be used by several threads
         at once.
-Line 885 
 MULTITHREADING
+Line 986 
 MULTITHREADING
  SAVING PRECOMPILED PATTERNS FOR LATER USE
         The compiled form of a regular expression can be saved and re-used at a
-        later time, possibly by a different program, and even on a  host  other
+        later  time,  possibly by a different program, and even on a host other
-        than  the  one  on  which  it  was  compiled.  Details are given in the
+        than the one on which  it  was  compiled.  Details  are  given  in  the
-        pcreprecompile documentation. However, compiling a  regular  expression
+        pcreprecompile  documentation.  However, compiling a regular expression
-        with  one version of PCRE for use with a different version is not guar-
+        with one version of PCRE for use with a different version is not  guar-
         anteed to work and may cause crashes.
-Line 896 
 CHECKING BUILD-TIME OPTIONS
+Line 997 
 CHECKING BUILD-TIME OPTIONS
         int pcre_config(int what, void *where);
-        The function pcre_config() makes it possible for a PCRE client to  dis-
+        The  function pcre_config() makes it possible for a PCRE client to dis-
         cover which optional features have been compiled into the PCRE library.
-        The pcrebuild documentation has more details about these optional  fea-
+        The  pcrebuild documentation has more details about these optional fea-
         tures.
-        The  first  argument  for pcre_config() is an integer, specifying which
+        The first argument for pcre_config() is an  integer,  specifying  which
         information is required; the second argument is a pointer to a variable
-        into  which  the  information  is  placed. The following information is
+        into which the information is  placed.  The  following  information  is
         available:
           PCRE_CONFIG_UTF8
-        The output is an integer that is set to one if UTF-8 support is  avail-
+        The  output is an integer that is set to one if UTF-8 support is avail-
         able; otherwise it is set to zero.
           PCRE_CONFIG_UNICODE_PROPERTIES
-        The  output  is  an  integer  that is set to one if support for Unicode
+        The output is an integer that is set to  one  if  support  for  Unicode
         character properties is available; otherwise it is set to zero.
           PCRE_CONFIG_NEWLINE
-        The output is an integer whose value specifies  the  default  character
+        The  output  is  an integer whose value specifies the default character
-        sequence  that is recognized as meaning "newline". The four values that
+        sequence that is recognized as meaning "newline". The four values  that
         are supported are: 10 for LF, 13 for CR, 3338 for CRLF, -2 for ANYCRLF,
-        and  -1  for  ANY. The default should normally be the standard sequence
+        and -1 for ANY. The default should normally be  the  standard  sequence
         for your operating system.
+          PCRE_CONFIG_BSR
+        The output is an integer whose value indicates what character sequences
+        the \R escape sequence matches by default. A value of 0 means  that  \R
+        matches  any  Unicode  line ending sequence; a value of 1 means that \R
+        matches only CR, LF, or CRLF. The default can be overridden when a pat-
+        tern is compiled or matched.
           PCRE_CONFIG_LINK_SIZE
-        The output is an integer that contains the number  of  bytes  used  for
+        The  output  is  an  integer that contains the number of bytes used for
         internal linkage in compiled regular expressions. The value is 2, 3, or
-. Larger values allow larger regular expressions to  be  compiled,  at
+.  Larger  values  allow larger regular expressions to be compiled, at
-        the  expense  of  slower matching. The default value of 2 is sufficient
+        the expense of slower matching. The default value of  2  is  sufficient
-        for all but the most massive patterns, since  it  allows  the  compiled
+        for  all  but  the  most massive patterns, since it allows the compiled
         pattern to be up to 64K in size.
           PCRE_CONFIG_POSIX_MALLOC_THRESHOLD
-        The  output  is  an integer that contains the threshold above which the
+        The output is an integer that contains the threshold  above  which  the
-        POSIX interface uses malloc() for output vectors. Further  details  are
+        POSIX  interface  uses malloc() for output vectors. Further details are
         given in the pcreposix documentation.
           PCRE_CONFIG_MATCH_LIMIT
         The output is an integer that gives the default limit for the number of
-        internal matching function calls in a  pcre_exec()  execution.  Further
+        internal  matching  function  calls in a pcre_exec() execution. Further
         details are given with pcre_exec() below.
           PCRE_CONFIG_MATCH_LIMIT_RECURSION
-        The  output is an integer that gives the default limit for the depth of
+        The output is an integer that gives the default limit for the depth  of
-        recursion when calling the internal matching function in a  pcre_exec()
+        recursion  when calling the internal matching function in a pcre_exec()
         execution. Further details are given with pcre_exec() below.
           PCRE_CONFIG_STACKRECURSE
-        The  output is an integer that is set to one if internal recursion when
+        The output is an integer that is set to one if internal recursion  when
         running pcre_exec() is implemented by recursive function calls that use
-        the  stack  to remember their state. This is the usual way that PCRE is
+        the stack to remember their state. This is the usual way that  PCRE  is
         compiled. The output is zero if PCRE was compiled to use blocks of data
-        on  the  heap  instead  of  recursive  function  calls.  In  this case,
+        on the  heap  instead  of  recursive  function  calls.  In  this  case,
-        pcre_stack_malloc and  pcre_stack_free  are  called  to  manage  memory
+        pcre_stack_malloc  and  pcre_stack_free  are  called  to  manage memory
         blocks on the heap, thus avoiding the use of the stack.
-Line 975 
 COMPILING A PATTERN
+Line 1084 
 COMPILING A PATTERN
         Either of the functions pcre_compile() or pcre_compile2() can be called
         to compile a pattern into an internal form. The only difference between
-        the  two interfaces is that pcre_compile2() has an additional argument,
+        the two interfaces is that pcre_compile2() has an additional  argument,
         errorcodeptr, via which a numerical error code can be returned.
         The pattern is a C string terminated by a binary zero, and is passed in
-        the  pattern  argument.  A  pointer to a single block of memory that is
+        the pattern argument. A pointer to a single block  of  memory  that  is
-        obtained via pcre_malloc is returned. This contains the  compiled  code
+        obtained  via  pcre_malloc is returned. This contains the compiled code
         and related data. The pcre type is defined for the returned block; this
         is a typedef for a structure whose contents are not externally defined.
         It is up to the caller to free the memory (via pcre_free) when it is no
         longer required.
-        Although the compiled code of a PCRE regex is relocatable, that is,  it
+        Although  the compiled code of a PCRE regex is relocatable, that is, it
         does not depend on memory location, the complete pcre data block is not
-        fully relocatable, because it may contain a copy of the tableptr  argu-
+        fully  relocatable, because it may contain a copy of the tableptr argu-
         ment, which is an address (see below).
         The options argument contains various bit settings that affect the com-
-        pilation. It should be zero if no options are required.  The  available
+        pilation.  It  should be zero if no options are required. The available
-        options  are  described  below. Some of them, in particular, those that
+        options are described below. Some of them, in  particular,  those  that
-        are compatible with Perl, can also be set and  unset  from  within  the
+        are  compatible  with  Perl,  can also be set and unset from within the
-        pattern  (see  the  detailed  description in the pcrepattern documenta-
+        pattern (see the detailed description  in  the  pcrepattern  documenta-
-        tion). For these options, the contents of the options  argument  speci-
+        tion).  For  these options, the contents of the options argument speci-
-        fies  their initial settings at the start of compilation and execution.
+        fies their initial settings at the start of compilation and  execution.
-        The PCRE_ANCHORED and PCRE_NEWLINE_xxx options can be set at  the  time
+        The  PCRE_ANCHORED  and PCRE_NEWLINE_xxx options can be set at the time
         of matching as well as at compile time.
         If errptr is NULL, pcre_compile() returns NULL immediately.  Otherwise,
-        if compilation of a pattern fails,  pcre_compile()  returns  NULL,  and
+        if  compilation  of  a  pattern fails, pcre_compile() returns NULL, and
         sets the variable pointed to by errptr to point to a textual error mes-
         sage. This is a static string that is part of the library. You must not
         try to free it. The offset from the start of the pattern to the charac-
         ter where the error was discovered is placed in the variable pointed to
-        by  erroffset,  which must not be NULL. If it is, an immediate error is
+        by erroffset, which must not be NULL. If it is, an immediate  error  is
         given.
-        If pcre_compile2() is used instead of pcre_compile(),  and  the  error-
+        If  pcre_compile2()  is  used instead of pcre_compile(), and the error-
-        codeptr  argument is not NULL, a non-zero error code number is returned
+        codeptr argument is not NULL, a non-zero error code number is  returned
-        via this argument in the event of an error. This is in addition to  the
+        via  this argument in the event of an error. This is in addition to the
         textual error message. Error codes and messages are listed below.
-        If  the  final  argument, tableptr, is NULL, PCRE uses a default set of
+        If the final argument, tableptr, is NULL, PCRE uses a  default  set  of
-        character tables that are  built  when  PCRE  is  compiled,  using  the
+        character  tables  that  are  built  when  PCRE  is compiled, using the
-        default  C  locale.  Otherwise, tableptr must be an address that is the
+        default C locale. Otherwise, tableptr must be an address  that  is  the
-        result of a call to pcre_maketables(). This value is  stored  with  the
+        result  of  a  call to pcre_maketables(). This value is stored with the
-        compiled  pattern,  and used again by pcre_exec(), unless another table
+        compiled pattern, and used again by pcre_exec(), unless  another  table
         pointer is passed to it. For more discussion, see the section on locale
         support below.
-        This  code  fragment  shows a typical straightforward call to pcre_com-
+        This code fragment shows a typical straightforward  call  to  pcre_com-
         pile():
           pcre *re;
-Line 1036 
 COMPILING A PATTERN
+Line 1145 
 COMPILING A PATTERN
             &erroffset,       /* for error offset */
             NULL);            /* use default character tables */
-        The following names for option bits are defined in  the  pcre.h  header
+        The  following  names  for option bits are defined in the pcre.h header
         file:
           PCRE_ANCHORED
         If this bit is set, the pattern is forced to be "anchored", that is, it
-        is constrained to match only at the first matching point in the  string
+        is  constrained to match only at the first matching point in the string
-        that  is being searched (the "subject string"). This effect can also be
+        that is being searched (the "subject string"). This effect can also  be
-        achieved by appropriate constructs in the pattern itself, which is  the
+        achieved  by appropriate constructs in the pattern itself, which is the
         only way to do it in Perl.
           PCRE_AUTO_CALLOUT
         If this bit is set, pcre_compile() automatically inserts callout items,
-        all with number 255, before each pattern item. For  discussion  of  the
+        all  with  number  255, before each pattern item. For discussion of the
         callout facility, see the pcrecallout documentation.
+          PCRE_BSR_ANYCRLF
+          PCRE_BSR_UNICODE
+        These options (which are mutually exclusive) control what the \R escape
+        sequence  matches.  The choice is either to match only CR, LF, or CRLF,
+        or to match any Unicode newline sequence. The default is specified when
+        PCRE is built. It can be overridden from within the pattern, or by set-
+        ting an option when a compiled pattern is matched.
           PCRE_CASELESS
-        If  this  bit is set, letters in the pattern match both upper and lower
+        If this bit is set, letters in the pattern match both upper  and  lower
-        case letters. It is equivalent to Perl's  /i  option,  and  it  can  be
+        case  letters.  It  is  equivalent  to  Perl's /i option, and it can be
-        changed  within a pattern by a (?i) option setting. In UTF-8 mode, PCRE
+        changed within a pattern by a (?i) option setting. In UTF-8 mode,  PCRE
-        always understands the concept of case for characters whose values  are
+        always  understands the concept of case for characters whose values are
-        less  than 128, so caseless matching is always possible. For characters
+        less than 128, so caseless matching is always possible. For  characters
-        with higher values, the concept of case is supported if  PCRE  is  com-
+        with  higher  values,  the concept of case is supported if PCRE is com-
-        piled  with Unicode property support, but not otherwise. If you want to
+        piled with Unicode property support, but not otherwise. If you want  to
-        use caseless matching for characters 128 and  above,  you  must  ensure
+        use  caseless  matching  for  characters 128 and above, you must ensure
-        that  PCRE  is  compiled  with Unicode property support as well as with
+        that PCRE is compiled with Unicode property support  as  well  as  with
         UTF-8 support.
           PCRE_DOLLAR_ENDONLY
-        If this bit is set, a dollar metacharacter in the pattern matches  only
+        If  this bit is set, a dollar metacharacter in the pattern matches only
-        at  the  end  of the subject string. Without this option, a dollar also
+        at the end of the subject string. Without this option,  a  dollar  also
-        matches immediately before a newline at the end of the string (but  not
+        matches  immediately before a newline at the end of the string (but not
-        before  any  other newlines). The PCRE_DOLLAR_ENDONLY option is ignored
+        before any other newlines). The PCRE_DOLLAR_ENDONLY option  is  ignored
-        if PCRE_MULTILINE is set.  There is no equivalent  to  this  option  in
+        if  PCRE_MULTILINE  is  set.   There is no equivalent to this option in
         Perl, and no way to set it within a pattern.
           PCRE_DOTALL
         If this bit is set, a dot metacharater in the pattern matches all char-
-        acters, including those that indicate newline. Without it, a  dot  does
+        acters,  including  those that indicate newline. Without it, a dot does
-        not  match  when  the  current position is at a newline. This option is
+        not match when the current position is at a  newline.  This  option  is
-        equivalent to Perl's /s option, and it can be changed within a  pattern
+        equivalent  to Perl's /s option, and it can be changed within a pattern
-        by  a (?s) option setting. A negative class such as [^a] always matches
+        by a (?s) option setting. A negative class such as [^a] always  matches
         newline characters, independent of the setting of this option.
           PCRE_DUPNAMES
-        If this bit is set, names used to identify capturing  subpatterns  need
+        If  this  bit is set, names used to identify capturing subpatterns need
         not be unique. This can be helpful for certain types of pattern when it
-        is known that only one instance of the named  subpattern  can  ever  be
+        is  known  that  only  one instance of the named subpattern can ever be
-        matched.  There  are  more details of named subpatterns below; see also
+        matched. There are more details of named subpatterns  below;  see  also
         the pcrepattern documentation.
           PCRE_EXTENDED
-        If this bit is set, whitespace  data  characters  in  the  pattern  are
+        If  this  bit  is  set,  whitespace  data characters in the pattern are
         totally ignored except when escaped or inside a character class. White-
         space does not include the VT character (code 11). In addition, charac-
         ters between an unescaped # outside a character class and the next new-
-        line, inclusive, are also ignored. This  is  equivalent  to  Perl's  /x
+        line,  inclusive,  are  also  ignored.  This is equivalent to Perl's /x
-        option,  and  it  can be changed within a pattern by a (?x) option set-
+        option, and it can be changed within a pattern by a  (?x)  option  set-
         ting.
-        This option makes it possible to include  comments  inside  complicated
+        This  option  makes  it possible to include comments inside complicated
-        patterns.   Note,  however,  that this applies only to data characters.
+        patterns.  Note, however, that this applies only  to  data  characters.
-        Whitespace  characters  may  never  appear  within  special   character
+        Whitespace   characters  may  never  appear  within  special  character
-        sequences  in  a  pattern,  for  example  within the sequence (?( which
+        sequences in a pattern, for  example  within  the  sequence  (?(  which
         introduces a conditional subpattern.
           PCRE_EXTRA
-        This option was invented in order to turn on  additional  functionality
+        This  option  was invented in order to turn on additional functionality
-        of  PCRE  that  is  incompatible with Perl, but it is currently of very
+        of PCRE that is incompatible with Perl, but it  is  currently  of  very
-        little use. When set, any backslash in a pattern that is followed by  a
+        little  use. When set, any backslash in a pattern that is followed by a
-        letter  that  has  no  special  meaning causes an error, thus reserving
+        letter that has no special meaning  causes  an  error,  thus  reserving
-        these combinations for future expansion. By  default,  as  in  Perl,  a
+        these  combinations  for  future  expansion.  By default, as in Perl, a
-        backslash  followed by a letter with no special meaning is treated as a
+        backslash followed by a letter with no special meaning is treated as  a
-        literal. (Perl can, however, be persuaded to give a warning for  this.)
+        literal.  (Perl can, however, be persuaded to give a warning for this.)
-        There  are  at  present no other features controlled by this option. It
+        There are at present no other features controlled by  this  option.  It
         can also be set by a (?X) option setting within a pattern.
           PCRE_FIRSTLINE
-        If this option is set, an  unanchored  pattern  is  required  to  match
+        If  this  option  is  set,  an  unanchored pattern is required to match
-        before  or  at  the  first  newline  in  the subject string, though the
+        before or at the first  newline  in  the  subject  string,  though  the
         matched text may continue over the newline.
           PCRE_MULTILINE
-        By default, PCRE treats the subject string as consisting  of  a  single
+        By  default,  PCRE  treats the subject string as consisting of a single
-        line  of characters (even if it actually contains newlines). The "start
+        line of characters (even if it actually contains newlines). The  "start
-        of line" metacharacter (^) matches only at the  start  of  the  string,
+        of  line"  metacharacter  (^)  matches only at the start of the string,
-        while  the  "end  of line" metacharacter ($) matches only at the end of
+        while the "end of line" metacharacter ($) matches only at  the  end  of
         the string, or before a terminating newline (unless PCRE_DOLLAR_ENDONLY
         is set). This is the same as Perl.
-        When  PCRE_MULTILINE  it  is set, the "start of line" and "end of line"
+        When PCRE_MULTILINE it is set, the "start of line" and  "end  of  line"
-        constructs match immediately following or immediately  before  internal
+        constructs  match  immediately following or immediately before internal
-        newlines  in  the  subject string, respectively, as well as at the very
+        newlines in the subject string, respectively, as well as  at  the  very
-        start and end. This is equivalent to Perl's /m option, and  it  can  be
+        start  and  end.  This is equivalent to Perl's /m option, and it can be
         changed within a pattern by a (?m) option setting. If there are no new-
-        lines in a subject string, or no occurrences of ^ or $  in  a  pattern,
+        lines  in  a  subject string, or no occurrences of ^ or $ in a pattern,
         setting PCRE_MULTILINE has no effect.
           PCRE_NEWLINE_CR
-Line 1149 
 COMPILING A PATTERN
+Line 1267 
 COMPILING A PATTERN
           PCRE_NEWLINE_ANYCRLF
           PCRE_NEWLINE_ANY
-        These  options  override the default newline definition that was chosen
+        These options override the default newline definition that  was  chosen
-        when PCRE was built. Setting the first or the second specifies  that  a
+        when  PCRE  was built. Setting the first or the second specifies that a
-        newline  is  indicated  by a single character (CR or LF, respectively).
+        newline is indicated by a single character (CR  or  LF,  respectively).
-        Setting PCRE_NEWLINE_CRLF specifies that a newline is indicated by  the
+        Setting  PCRE_NEWLINE_CRLF specifies that a newline is indicated by the
-        two-character  CRLF  sequence.  Setting  PCRE_NEWLINE_ANYCRLF specifies
+        two-character CRLF  sequence.  Setting  PCRE_NEWLINE_ANYCRLF  specifies
         that any of the three preceding sequences should be recognized. Setting
-        PCRE_NEWLINE_ANY  specifies that any Unicode newline sequence should be
+        PCRE_NEWLINE_ANY specifies that any Unicode newline sequence should  be
         recognized. The Unicode newline sequences are the three just mentioned,
-        plus  the  single  characters  VT (vertical tab, U+000B), FF (formfeed,
+        plus the single characters VT (vertical  tab,  U+000B),  FF  (formfeed,
-        U+000C), NEL (next line, U+0085), LS (line separator, U+2028),  and  PS
+        U+000C),  NEL  (next line, U+0085), LS (line separator, U+2028), and PS
-        (paragraph  separator,  U+2029).  The  last  two are recognized only in
+        (paragraph separator, U+2029). The last  two  are  recognized  only  in
         UTF-8 mode.
-        The newline setting in the  options  word  uses  three  bits  that  are
+        The  newline  setting  in  the  options  word  uses three bits that are
         treated as a number, giving eight possibilities. Currently only six are
-        used (default plus the five values above). This means that if  you  set
+        used  (default  plus the five values above). This means that if you set
-        more  than one newline option, the combination may or may not be sensi-
+        more than one newline option, the combination may or may not be  sensi-
         ble. For example, PCRE_NEWLINE_CR with PCRE_NEWLINE_LF is equivalent to
-        PCRE_NEWLINE_CRLF,  but other combinations may yield unused numbers and
+        PCRE_NEWLINE_CRLF, but other combinations may yield unused numbers  and
         cause an error.
-        The only time that a line break is specially recognized when  compiling
+        The  only time that a line break is specially recognized when compiling
-        a  pattern  is  if  PCRE_EXTENDED  is set, and an unescaped # outside a
+        a pattern is if PCRE_EXTENDED is set, and  an  unescaped  #  outside  a
-        character class is encountered. This indicates  a  comment  that  lasts
+        character  class  is  encountered.  This indicates a comment that lasts
-        until  after the next line break sequence. In other circumstances, line
+        until after the next line break sequence. In other circumstances,  line
-        break  sequences  are  treated  as  literal  data,   except   that   in
+        break   sequences   are   treated  as  literal  data,  except  that  in
         PCRE_EXTENDED mode, both CR and LF are treated as whitespace characters
         and are therefore ignored.
         The newline option that is set at compile time becomes the default that
-        is  used for pcre_exec() and pcre_dfa_exec(), but it can be overridden.
+        is used for pcre_exec() and pcre_dfa_exec(), but it can be  overridden.
           PCRE_NO_AUTO_CAPTURE
         If this option is set, it disables the use of numbered capturing paren-
-        theses  in the pattern. Any opening parenthesis that is not followed by
+        theses in the pattern. Any opening parenthesis that is not followed  by
-        ? behaves as if it were followed by ?: but named parentheses can  still
+        ?  behaves as if it were followed by ?: but named parentheses can still
-        be  used  for  capturing  (and  they acquire numbers in the usual way).
+        be used for capturing (and they acquire  numbers  in  the  usual  way).
         There is no equivalent of this option in Perl.
           PCRE_UNGREEDY
-        This option inverts the "greediness" of the quantifiers  so  that  they
+        This  option  inverts  the "greediness" of the quantifiers so that they
-        are  not greedy by default, but become greedy if followed by "?". It is
+        are not greedy by default, but become greedy if followed by "?". It  is
-        not compatible with Perl. It can also be set by a (?U)  option  setting
+        not  compatible  with Perl. It can also be set by a (?U) option setting
         within the pattern.
           PCRE_UTF8
-        This  option  causes PCRE to regard both the pattern and the subject as
+        This option causes PCRE to regard both the pattern and the  subject  as
-        strings of UTF-8 characters instead of single-byte  character  strings.
+        strings  of  UTF-8 characters instead of single-byte character strings.
-        However,  it is available only when PCRE is built to include UTF-8 sup-
+        However, it is available only when PCRE is built to include UTF-8  sup-
-        port. If not, the use of this option provokes an error. Details of  how
+        port.  If not, the use of this option provokes an error. Details of how
-        this  option  changes the behaviour of PCRE are given in the section on
+        this option changes the behaviour of PCRE are given in the  section  on
         UTF-8 support in the main pcre page.
           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
-Line 1237 
 COMPILATION ERROR CODES
+Line 1356 
 COMPILATION ERROR CODES
  nothing to repeat
  [this code is not in use]
  internal error: unexpected repeat
- unrecognized character after (?
+ unrecognized character after (? or (?-
  POSIX named classes are supported only within a class
  missing )
  reference to non-existent subpattern
-Line 1245 
 COMPILATION ERROR CODES
+Line 1364 
 COMPILATION ERROR CODES
  unknown option bit(s) set
  missing ) after comment
  [this code is not in use]
- regular expression too large
+ regular expression is too large
  failed to get memory
  unmatched parentheses
  internal error: code overflow
-Line 1254 
 COMPILATION ERROR CODES
+Line 1373 
 COMPILATION ERROR CODES
  malformed number or name after (?(
  conditional group contains more than two branches
  assertion expected after (?(
- (?R or (?digits must be followed by )
+ (?R or (?[+-]digits must be followed by )
  unknown POSIX class name
  POSIX collating elements are not supported
  this version of PCRE is not compiled with PCRE_UTF8 support
-Line 1274 
 COMPILATION ERROR CODES
+Line 1393 
 COMPILATION ERROR CODES
  malformed \P or \p sequence
  unknown property name after \P or \p
  subpattern name is too long (maximum 32 characters)
- too many named subpatterns (maximum 10,000)
+ too many named subpatterns (maximum 10000)
- 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
         found
  DEFINE group contains more than one branch
  repeating a DEFINE group is not allowed
- inconsistent NEWLINE options"
+ inconsistent NEWLINE options
+ \g is not followed by a braced name or an optionally braced
+                non-zero number
+ (?+ or (?- or (?(+ or (?(- must be followed by a non-zero number
+ (*VERB) with an argument is not supported
+ (*VERB) not recognized
+ number is too big
+ subpattern name expected
+ digit expected after (?+
+        The numbers 32 and 10000 in errors 48 and 49  are  defaults;  different
+        values may be used if the limits were changed when PCRE was built.
  STUDYING A PATTERN
-Line 1290 
 STUDYING A PATTERN
+Line 1420 
 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 1327 
 STUDYING A PATTERN
+Line 1457 
 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 1392 
 INFORMATION ABOUT A PATTERN
+Line 1522 
 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 1408 
 INFORMATION ABOUT A PATTERN
+Line 1538 
 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 1421 
 INFORMATION ABOUT A PATTERN
+Line 1551 
 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_HASCRORLF
+        Return 1 if the pattern contains any explicit  matches  for  CR  or  LF
+        characters,  otherwise  0.  The  fourth argument should point to an int
+        variable. An explicit match is either a literal CR or LF character,  or
+        \r or \n.
+          PCRE_INFO_JCHANGED
+        Return  1  if  the (?J) or (?-J) option setting is used in the pattern,
+        otherwise 0. The fourth argument should point to an int variable.  (?J)
+        and (?-J) set and unset the local PCRE_DUPNAMES option, respectively.
           PCRE_INFO_LASTLITERAL
         Return  the  value of the rightmost literal byte that must exist in any
-Line 1525 
 INFORMATION ABOUT A PATTERN
+Line 1668 
 INFORMATION ABOUT A PATTERN
         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.
+        The fourth argument should point to an int  variable.  The  pcrepartial
+        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 1546 
 INFORMATION ABOUT A PATTERN
+Line 1700 
 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 1554 
 INFORMATION ABOUT A PATTERN
+Line 1708 
 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 1564 
 OBSOLETE INFO FUNCTION
+Line 1718 
 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 1586 
 REFERENCE COUNTS
+Line 1740 
 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 1610 
 MATCHING A PATTERN: THE TRADITIONAL FUNC
+Line 1764 
 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 1640 
 MATCHING A PATTERN: THE TRADITIONAL FUNC
+Line 1794 
 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 1653 
 MATCHING A PATTERN: THE TRADITIONAL FUNC
+Line 1807 
 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 1662 
 MATCHING A PATTERN: THE TRADITIONAL FUNC
+Line 1816 
 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_BSR_ANYCRLF
+          PCRE_BSR_UNICODE
+        These options (which are mutually exclusive) control what the \R escape
+        sequence matches. The choice is either to match only CR, LF,  or  CRLF,
+        or  to  match  any Unicode newline sequence. These options override the
+        choice that was made or defaulted when the pattern was compiled.
           PCRE_NEWLINE_CR
           PCRE_NEWLINE_LF
           PCRE_NEWLINE_CRLF
-Line 1744 
 MATCHING A PATTERN: THE TRADITIONAL FUNC
+Line 1906 
 MATCHING A PATTERN: THE TRADITIONAL FUNC
         tion of pcre_compile()  above.  During  matching,  the  newline  choice
         affects  the  behaviour  of the dot, circumflex, and dollar metacharac-
         ters. It may also alter the way the match position is advanced after  a
-        match  failure  for  an  unanchored  pattern.  When  PCRE_NEWLINE_CRLF,
+        match failure for an unanchored pattern.
-        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-
+        When  PCRE_NEWLINE_CRLF,  PCRE_NEWLINE_ANYCRLF,  or PCRE_NEWLINE_ANY is
-        tion is advanced by two characters instead of one, in other  words,  to
+        set, and a match attempt for an unanchored pattern fails when the  cur-
-        after the CRLF.
+        rent  position  is  at  a  CRLF  sequence,  and the pattern contains no
+        explicit matches for  CR  or  LF  characters,  the  match  position  is
+        advanced by two characters instead of one, in other words, to after the
+        CRLF.
+        The above rule is a compromise that makes the most common cases work as
+        expected.  For  example,  if  the  pattern  is .+A (and the PCRE_DOTALL
+        option is not set), it does not match the string "\r\nA" because, after
+        failing  at the start, it skips both the CR and the LF before retrying.
+        However, the pattern [\r\n]A does match that string,  because  it  con-
+        tains an explicit CR or LF reference, and so advances only by one char-
+        acter after the first failure.
+        An explicit match for CR of LF is either a literal appearance of one of
+        those  characters,  or  one  of the \r or \n escape sequences. Implicit
+        matches such as [^X] do not count, nor does \s (which includes  CR  and
+        LF in the characters that it matches).
+        Notwithstanding  the above, anomalous effects may still occur when CRLF
+        is a valid newline sequence and explicit \r or \n escapes appear in the
+        pattern.
           PCRE_NOTBOL
-Line 1795 
 MATCHING A PATTERN: THE TRADITIONAL FUNC
+Line 1977 
 MATCHING A PATTERN: THE TRADITIONAL FUNC
         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
         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
+        If you already know that your subject is valid, and you  want  to  skip
-        PCRE_NO_UTF8_CHECK  option  when calling pcre_exec(). You might want to
+        these    checks    for   performance   reasons,   you   can   set   the
-        do this for the second and subsequent calls to pcre_exec() if  you  are
+        PCRE_NO_UTF8_CHECK option when calling pcre_exec(). You might  want  to
-        making  repeated  calls  to  find  all  the matches in a single subject
+        do  this  for the second and subsequent calls to pcre_exec() if you are
-        string. However, you should be  sure  that  the  value  of  startoffset
+        making repeated calls to find all  the  matches  in  a  single  subject
-        points  to  the  start of a UTF-8 character. When PCRE_NO_UTF8_CHECK is
+        string.  However,  you  should  be  sure  that the value of startoffset
-        set, the effect of passing an invalid UTF-8 string as a subject,  or  a
+        points to the start of a UTF-8 character.  When  PCRE_NO_UTF8_CHECK  is
-        value  of startoffset that does not point to the start of a UTF-8 char-
+        set,  the  effect of passing an invalid UTF-8 string as a subject, or a
+        value of startoffset that does not point to the start of a UTF-8  char-
         acter, is undefined. Your program may crash.
           PCRE_PARTIAL
-        This option turns on the  partial  matching  feature.  If  the  subject
+        This  option  turns  on  the  partial  matching feature. If the subject
-        string  fails to match the pattern, but at some point during the match-
+        string fails to match the pattern, but at some point during the  match-
-        ing process the end of the subject was reached (that  is,  the  subject
+        ing  process  the  end of the subject was reached (that is, the subject
-        partially  matches  the  pattern and the failure to match occurred only
+        partially matches the pattern and the failure to  match  occurred  only
-        because there were not enough subject characters), pcre_exec()  returns
+        because  there were not enough subject characters), pcre_exec() returns
-        PCRE_ERROR_PARTIAL  instead of PCRE_ERROR_NOMATCH. When PCRE_PARTIAL is
+        PCRE_ERROR_PARTIAL instead of PCRE_ERROR_NOMATCH. When PCRE_PARTIAL  is
-        used, there are restrictions on what may appear in the  pattern.  These
+        used,  there  are restrictions on what may appear in the pattern. These
         are discussed in the pcrepartial documentation.
     The string to be matched by pcre_exec()
-        The  subject string is passed to pcre_exec() as a pointer in subject, a
+        The subject string is passed to pcre_exec() as a pointer in subject,  a
-        length in length, and a starting byte offset in startoffset.  In  UTF-8
+        length  in  length, and a starting byte offset in startoffset. In UTF-8
-        mode,  the  byte  offset  must point to the start of a UTF-8 character.
+        mode, the byte offset must point to the start  of  a  UTF-8  character.
-        Unlike the pattern string, the subject may contain binary  zero  bytes.
+        Unlike  the  pattern string, the subject may contain binary zero bytes.
-        When  the starting offset is zero, the search for a match starts at the
+        When the starting offset is zero, the search for a match starts at  the
         beginning of the subject, and this is by far the most common case.
-        A non-zero starting offset is useful when searching for  another  match
+        A  non-zero  starting offset is useful when searching for another match
-        in  the same subject by calling pcre_exec() again after a previous suc-
+        in the same subject by calling pcre_exec() again after a previous  suc-
-        cess.  Setting startoffset differs from just passing over  a  shortened
+        cess.   Setting  startoffset differs from just passing over a shortened
-        string  and  setting  PCRE_NOTBOL  in the case of a pattern that begins
+        string and setting PCRE_NOTBOL in the case of  a  pattern  that  begins
         with any kind of lookbehind. For example, consider the pattern
           \Biss\B
-        which finds occurrences of "iss" in the middle of  words.  (\B  matches
+        which  finds  occurrences  of "iss" in the middle of words. (\B matches
-        only  if  the  current position in the subject is not a word boundary.)
+        only if the current position in the subject is not  a  word  boundary.)
-        When applied to the string "Mississipi" the first call  to  pcre_exec()
+        When  applied  to the string "Mississipi" the first call to pcre_exec()
-        finds  the  first  occurrence. If pcre_exec() is called again with just
+        finds the first occurrence. If pcre_exec() is called  again  with  just
-        the remainder of the subject,  namely  "issipi",  it  does  not  match,
+        the  remainder  of  the  subject,  namely  "issipi", it does not match,
         because \B is always false at the start of the subject, which is deemed
-        to be a word boundary. However, if pcre_exec()  is  passed  the  entire
+        to  be  a  word  boundary. However, if pcre_exec() is passed the entire
         string again, but with startoffset set to 4, it finds the second occur-
-        rence of "iss" because it is able to look behind the starting point  to
+        rence  of "iss" because it is able to look behind the starting point to
         discover that it is preceded by a letter.
-        If  a  non-zero starting offset is passed when the pattern is anchored,
+        If a non-zero starting offset is passed when the pattern  is  anchored,
         one attempt to match at the given offset is made. This can only succeed
-        if  the  pattern  does  not require the match to be at the start of the
+        if the pattern does not require the match to be at  the  start  of  the
         subject.
     How pcre_exec() returns captured substrings
-        In general, a pattern matches a certain portion of the subject, and  in
+        In  general, a pattern matches a certain portion of the subject, and in
-        addition,  further  substrings  from  the  subject may be picked out by
+        addition, further substrings from the subject  may  be  picked  out  by
-        parts of the pattern. Following the usage  in  Jeffrey  Friedl's  book,
+        parts  of  the  pattern.  Following the usage in Jeffrey Friedl's book,
-        this  is  called "capturing" in what follows, and the phrase "capturing
+        this is called "capturing" in what follows, and the  phrase  "capturing
-        subpattern" is used for a fragment of a pattern that picks out  a  sub-
+        subpattern"  is  used for a fragment of a pattern that picks out a sub-
-        string.  PCRE  supports several other kinds of parenthesized subpattern
+        string. PCRE supports several other kinds of  parenthesized  subpattern
         that do not cause substrings to be captured.
-        Captured substrings are returned to the caller via a vector of  integer
+        Captured  substrings are returned to the caller via a vector of integer
-        offsets  whose  address is passed in ovector. The number of elements in
+        offsets whose address is passed in ovector. The number of  elements  in
-        the vector is passed in ovecsize, which must be a non-negative  number.
+        the  vector is passed in ovecsize, which must be a non-negative number.
         Note: this argument is NOT the size of ovector in bytes.
-        The  first  two-thirds of the vector is used to pass back captured sub-
+        The first two-thirds of the vector is used to pass back  captured  sub-
-        strings, each substring using a pair of integers. The  remaining  third
+        strings,  each  substring using a pair of integers. The remaining third
-        of  the  vector is used as workspace by pcre_exec() while matching cap-
+        of the vector is used as workspace by pcre_exec() while  matching  cap-
-        turing subpatterns, and is not available for passing back  information.
+        turing  subpatterns, and is not available for passing back information.
-        The  length passed in ovecsize should always be a multiple of three. If
+        The length passed in ovecsize should always be a multiple of three.  If
         it is not, it is rounded down.
-        When a match is successful, information about  captured  substrings  is
+        When  a  match  is successful, information about captured substrings is
-        returned  in  pairs  of integers, starting at the beginning of ovector,
+        returned in pairs of integers, starting at the  beginning  of  ovector,
-        and continuing up to two-thirds of its length at the  most.  The  first
+        and  continuing  up  to two-thirds of its length at the most. The first
         element of a pair is set to the offset of the first character in a sub-
-        string, and the second is set to the  offset  of  the  first  character
+        string,  and  the  second  is  set to the offset of the first character
-        after  the  end  of  a  substring. The first pair, ovector[0] and ovec-
+        after the end of a substring. The  first  pair,  ovector[0]  and  ovec-
-        tor[1], identify the portion of  the  subject  string  matched  by  the
+        tor[1],  identify  the  portion  of  the  subject string matched by the
-        entire  pattern.  The next pair is used for the first capturing subpat-
+        entire pattern. The next pair is used for the first  capturing  subpat-
         tern, and so on. The value returned by pcre_exec() is one more than the
         highest numbered pair that has been set. For example, if two substrings
-        have been captured, the returned value is 3. If there are no  capturing
+        have  been captured, the returned value is 3. If there are no capturing
-        subpatterns,  the return value from a successful match is 1, indicating
+        subpatterns, the return value from a successful match is 1,  indicating
         that just the first pair of offsets has been set.
         If a capturing subpattern is matched repeatedly, it is the last portion
         of the string that it matched that is returned.
-        If  the vector is too small to hold all the captured substring offsets,
+        If the vector is too small to hold all the captured substring  offsets,
         it is used as far as possible (up to two-thirds of its length), and the
-        function  returns a value of zero. In particular, if the substring off-
+        function returns a value of zero. In particular, if the substring  off-
         sets are not of interest, pcre_exec() may be called with ovector passed
-        as  NULL  and  ovecsize  as zero. However, if the pattern contains back
+        as NULL and ovecsize as zero. However, if  the  pattern  contains  back
-        references and the ovector is not big enough to  remember  the  related
+        references  and  the  ovector is not big enough to remember the related
-        substrings,  PCRE has to get additional memory for use during matching.
+        substrings, PCRE has to get additional memory for use during  matching.
         Thus it is usually advisable to supply an ovector.
-        The pcre_info() function can be used to find  out  how  many  capturing
+        The  pcre_info()  function  can  be used to find out how many capturing
-        subpatterns  there  are  in  a  compiled pattern. The smallest size for
+        subpatterns there are in a compiled  pattern.  The  smallest  size  for
-        ovector that will allow for n captured substrings, in addition  to  the
+        ovector  that  will allow for n captured substrings, in addition to the
         offsets of the substring matched by the whole pattern, is (n+1)*3.
-        It  is  possible for capturing subpattern number n+1 to match some part
+        It is possible for capturing subpattern number n+1 to match  some  part
         of the subject when subpattern n has not been used at all. For example,
-        if  the  string  "abc"  is  matched against the pattern (a|(z))(bc) the
+        if the string "abc" is matched  against  the  pattern  (a|(z))(bc)  the
         return from the function is 4, and subpatterns 1 and 3 are matched, but
- is  not.  When  this happens, both values in the offset pairs corre-
+is not. When this happens, both values in  the  offset  pairs  corre-
         sponding to unused subpatterns are set to -1.
-        Offset values that correspond to unused subpatterns at the end  of  the
+        Offset  values  that correspond to unused subpatterns at the end of the
-        expression  are  also  set  to  -1. For example, if the string "abc" is
+        expression are also set to -1. For example,  if  the  string  "abc"  is
-        matched against the pattern (abc)(x(yz)?)? subpatterns 2 and 3 are  not
+        matched  against the pattern (abc)(x(yz)?)? subpatterns 2 and 3 are not
-        matched.  The  return  from the function is 2, because the highest used
+        matched. The return from the function is 2, because  the  highest  used
         capturing subpattern number is 1. However, you can refer to the offsets
-        for  the  second  and third capturing subpatterns if you wish (assuming
+        for the second and third capturing subpatterns if  you  wish  (assuming
         the vector is large enough, of course).
-        Some convenience functions are provided  for  extracting  the  captured
+        Some  convenience  functions  are  provided for extracting the captured
         substrings as separate strings. These are described below.
     Error return values from pcre_exec()
-        If  pcre_exec()  fails, it returns a negative number. The following are
+        If pcre_exec() fails, it returns a negative number. The  following  are
         defined in the header file:
           PCRE_ERROR_NOMATCH        (-1)
-Line 1937 
 MATCHING A PATTERN: THE TRADITIONAL FUNC
+Line 2120 
 MATCHING A PATTERN: THE TRADITIONAL FUNC
           PCRE_ERROR_NULL           (-2)
-        Either code or subject was passed as NULL,  or  ovector  was  NULL  and
+        Either  code  or  subject  was  passed as NULL, or ovector was NULL and
         ovecsize was not zero.
           PCRE_ERROR_BADOPTION      (-3)
-Line 1946 
 MATCHING A PATTERN: THE TRADITIONAL FUNC
+Line 2129 
 MATCHING A PATTERN: THE TRADITIONAL FUNC
           PCRE_ERROR_BADMAGIC       (-4)
-        PCRE  stores a 4-byte "magic number" at the start of the compiled code,
+        PCRE stores a 4-byte "magic number" at the start of the compiled  code,
         to catch the case when it is passed a junk pointer and to detect when a
         pattern that was compiled in an environment of one endianness is run in
-        an environment with the other endianness. This is the error  that  PCRE
+        an  environment  with the other endianness. This is the error that PCRE
         gives when the magic number is not present.
           PCRE_ERROR_UNKNOWN_OPCODE (-5)
         While running the pattern match, an unknown item was encountered in the
-        compiled pattern. This error could be caused by a bug  in  PCRE  or  by
+        compiled  pattern.  This  error  could be caused by a bug in PCRE or by
         overwriting of the compiled pattern.
           PCRE_ERROR_NOMEMORY       (-6)
-        If  a  pattern contains back references, but the ovector that is passed
+        If a pattern contains back references, but the ovector that  is  passed
         to pcre_exec() is not big enough to remember the referenced substrings,
-        PCRE  gets  a  block of memory at the start of matching to use for this
+        PCRE gets a block of memory at the start of matching to  use  for  this
-        purpose. If the call via pcre_malloc() fails, this error is given.  The
+        purpose.  If the call via pcre_malloc() fails, this error is given. The
         memory is automatically freed at the end of matching.
           PCRE_ERROR_NOSUBSTRING    (-7)
-        This  error is used by the pcre_copy_substring(), pcre_get_substring(),
+        This error is used by the pcre_copy_substring(),  pcre_get_substring(),
         and  pcre_get_substring_list()  functions  (see  below).  It  is  never
         returned by pcre_exec().
           PCRE_ERROR_MATCHLIMIT     (-8)
-        The  backtracking  limit,  as  specified  by the match_limit field in a
+        The backtracking limit, as specified by  the  match_limit  field  in  a
-        pcre_extra structure (or defaulted) was reached.  See  the  description
+        pcre_extra  structure  (or  defaulted) was reached. See the description
         above.
           PCRE_ERROR_CALLOUT        (-9)
         This error is never generated by pcre_exec() itself. It is provided for
-        use by callout functions that want to yield a distinctive  error  code.
+        use  by  callout functions that want to yield a distinctive error code.
         See the pcrecallout documentation for details.
           PCRE_ERROR_BADUTF8        (-10)
-        A  string  that contains an invalid UTF-8 byte sequence was passed as a
+        A string that contains an invalid UTF-8 byte sequence was passed  as  a
         subject.
           PCRE_ERROR_BADUTF8_OFFSET (-11)
         The UTF-8 byte sequence that was passed as a subject was valid, but the
-        value  of startoffset did not point to the beginning of a UTF-8 charac-
+        value of startoffset did not point to the beginning of a UTF-8  charac-
         ter.
           PCRE_ERROR_PARTIAL        (-12)
-        The subject string did not match, but it did match partially.  See  the
+        The  subject  string did not match, but it did match partially. See the
         pcrepartial documentation for details of partial matching.
           PCRE_ERROR_BADPARTIAL     (-13)
-        The  PCRE_PARTIAL  option  was  used with a compiled pattern containing
+        The PCRE_PARTIAL option was used with  a  compiled  pattern  containing
-        items that are not supported for partial matching. See the  pcrepartial
+        items  that are not supported for partial matching. See the pcrepartial
         documentation for details of partial matching.
           PCRE_ERROR_INTERNAL       (-14)
-        An  unexpected  internal error has occurred. This error could be caused
+        An unexpected internal error has occurred. This error could  be  caused
         by a bug in PCRE or by overwriting of the compiled pattern.
           PCRE_ERROR_BADCOUNT       (-15)
-        This error is given if the value of the ovecsize argument is  negative.
+        This  error is given if the value of the ovecsize argument is negative.
           PCRE_ERROR_RECURSIONLIMIT (-21)
         The internal recursion limit, as specified by the match_limit_recursion
-        field in a pcre_extra structure (or defaulted)  was  reached.  See  the
+        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 2049 
 EXTRACTING CAPTURED SUBSTRINGS BY NUMBER
+Line 2224 
 EXTRACTING CAPTURED SUBSTRINGS BY NUMBER
         int pcre_get_substring_list(const char *subject,
              int *ovector, int stringcount, const char ***listptr);
-        Captured  substrings  can  be  accessed  directly  by using the offsets
+        Captured substrings can be  accessed  directly  by  using  the  offsets
-        returned by pcre_exec() in  ovector.  For  convenience,  the  functions
+        returned  by  pcre_exec()  in  ovector.  For convenience, the functions
         pcre_copy_substring(),    pcre_get_substring(),    and    pcre_get_sub-
-        string_list() are provided for extracting captured substrings  as  new,
+        string_list()  are  provided for extracting captured substrings as new,
-        separate,  zero-terminated strings. These functions identify substrings
+        separate, zero-terminated strings. These functions identify  substrings
-        by number. The next section describes functions  for  extracting  named
+        by  number.  The  next section describes functions for extracting named
         substrings.
-        A  substring that contains a binary zero is correctly extracted and has
+        A substring that contains a binary zero is correctly extracted and  has
-        a further zero added on the end, but the result is not, of course, a  C
+        a  further zero added on the end, but the result is not, of course, a C
-        string.   However,  you  can  process such a string by referring to the
+        string.  However, you can process such a string  by  referring  to  the
-        length that is  returned  by  pcre_copy_substring()  and  pcre_get_sub-
+        length  that  is  returned  by  pcre_copy_substring() and pcre_get_sub-
         string().  Unfortunately, the interface to pcre_get_substring_list() is
-        not adequate for handling strings containing binary zeros, because  the
+        not  adequate for handling strings containing binary zeros, because the
         end of the final string is not independently indicated.
-        The  first  three  arguments  are the same for all three of these func-
+        The first three arguments are the same for all  three  of  these  func-
-        tions: subject is the subject string that has  just  been  successfully
+        tions:  subject  is  the subject string that has just been successfully
         matched, ovector is a pointer to the vector of integer offsets that was
         passed to pcre_exec(), and stringcount is the number of substrings that
-        were  captured  by  the match, including the substring that matched the
+        were captured by the match, including the substring  that  matched  the
         entire regular expression. This is the value returned by pcre_exec() if
-        it  is greater than zero. If pcre_exec() returned zero, indicating that
+        it is greater than zero. If pcre_exec() returned zero, indicating  that
-        it ran out of space in ovector, the value passed as stringcount  should
+        it  ran out of space in ovector, the value passed as stringcount should
         be the number of elements in the vector divided by three.
-        The  functions pcre_copy_substring() and pcre_get_substring() extract a
+        The functions pcre_copy_substring() and pcre_get_substring() extract  a
-        single substring, whose number is given as  stringnumber.  A  value  of
+        single  substring,  whose  number  is given as stringnumber. A value of
-        zero  extracts  the  substring that matched the entire pattern, whereas
+        zero extracts the substring that matched the  entire  pattern,  whereas
-        higher values  extract  the  captured  substrings.  For  pcre_copy_sub-
+        higher  values  extract  the  captured  substrings.  For pcre_copy_sub-
-        string(),  the  string  is  placed  in buffer, whose length is given by
+        string(), the string is placed in buffer,  whose  length  is  given  by
-        buffersize, while for pcre_get_substring() a new  block  of  memory  is
+        buffersize,  while  for  pcre_get_substring()  a new block of memory is
-        obtained  via  pcre_malloc,  and its address is returned via stringptr.
+        obtained via pcre_malloc, and its address is  returned  via  stringptr.
-        The yield of the function is the length of the  string,  not  including
+        The  yield  of  the function is the length of the string, not including
         the terminating zero, or one of these error codes:
           PCRE_ERROR_NOMEMORY       (-6)
-        The  buffer  was too small for pcre_copy_substring(), or the attempt to
+        The buffer was too small for pcre_copy_substring(), or the  attempt  to
         get memory failed for pcre_get_substring().
           PCRE_ERROR_NOSUBSTRING    (-7)
         There is no substring whose number is stringnumber.
-        The pcre_get_substring_list()  function  extracts  all  available  sub-
+        The  pcre_get_substring_list()  function  extracts  all  available sub-
-        strings  and  builds  a list of pointers to them. All this is done in a
+        strings and builds a list of pointers to them. All this is  done  in  a
         single block of memory that is obtained via pcre_malloc. The address of
-        the  memory  block  is returned via listptr, which is also the start of
+        the memory block is returned via listptr, which is also  the  start  of
-        the list of string pointers. The end of the list is marked  by  a  NULL
+        the  list  of  string pointers. The end of the list is marked by a NULL
-        pointer.  The  yield  of  the function is zero if all went well, or the
+        pointer. The yield of the function is zero if all  went  well,  or  the
         error code
           PCRE_ERROR_NOMEMORY       (-6)
         if the attempt to get the memory block failed.
-        When any of these functions encounter a substring that is unset,  which
+        When  any of these functions encounter a substring that is unset, which
-        can  happen  when  capturing subpattern number n+1 matches some part of
+        can happen when capturing subpattern number n+1 matches  some  part  of
-        the subject, but subpattern n has not been used at all, they return  an
+        the  subject, but subpattern n has not been used at all, they return an
         empty string. This can be distinguished from a genuine zero-length sub-
-        string by inspecting the appropriate offset in ovector, which is  nega-
+        string  by inspecting the appropriate offset in ovector, which is nega-
         tive for unset substrings.
-        The  two convenience functions pcre_free_substring() and pcre_free_sub-
+        The two convenience functions pcre_free_substring() and  pcre_free_sub-
-        string_list() can be used to free the memory  returned  by  a  previous
+        string_list()  can  be  used  to free the memory returned by a previous
         call  of  pcre_get_substring()  or  pcre_get_substring_list(),  respec-
-        tively. They do nothing more than  call  the  function  pointed  to  by
+        tively.  They  do  nothing  more  than  call the function pointed to by
-        pcre_free,  which  of course could be called directly from a C program.
+        pcre_free, which of course could be called directly from a  C  program.
-        However, PCRE is used in some situations where it is linked via a  spe-
+        However,  PCRE is used in some situations where it is linked via a spe-
-        cial   interface  to  another  programming  language  that  cannot  use
+        cial  interface  to  another  programming  language  that  cannot   use
-        pcre_free directly; it is for these cases that the functions  are  pro-
+        pcre_free  directly;  it is for these cases that the functions are pro-
         vided.
-Line 2139 
 EXTRACTING CAPTURED SUBSTRINGS BY NAME
+Line 2314 
 EXTRACTING CAPTURED SUBSTRINGS BY NAME
              int stringcount, const char *stringname,
              const char **stringptr);
-        To  extract a substring by name, you first have to find associated num-
+        To extract a substring by name, you first have to find associated  num-
         ber.  For example, for this pattern
           (a+)b(?<xxx>\d+)...
-Line 2148 
 EXTRACTING CAPTURED SUBSTRINGS BY NAME
+Line 2323 
 EXTRACTING CAPTURED SUBSTRINGS BY NAME
         be unique (PCRE_DUPNAMES was not set), you can find the number from the
         name by calling pcre_get_stringnumber(). The first argument is the com-
         piled pattern, and the second is the name. The yield of the function is
-        the subpattern number, or PCRE_ERROR_NOSUBSTRING (-7) if  there  is  no
+        the  subpattern  number,  or PCRE_ERROR_NOSUBSTRING (-7) if there is no
         subpattern of that name.
         Given the number, you can extract the substring directly, or use one of
         the functions described in the previous section. For convenience, there
         are also two functions that do the whole job.
-        Most    of    the    arguments   of   pcre_copy_named_substring()   and
+        Most   of   the   arguments    of    pcre_copy_named_substring()    and
-        pcre_get_named_substring() are the same  as  those  for  the  similarly
+        pcre_get_named_substring()  are  the  same  as  those for the similarly
-        named  functions  that extract by number. As these are described in the
+        named functions that extract by number. As these are described  in  the
-        previous section, they are not re-described here. There  are  just  two
+        previous  section,  they  are not re-described here. There are just two
         differences:
-        First,  instead  of a substring number, a substring name is given. Sec-
+        First, instead of a substring number, a substring name is  given.  Sec-
         ond, there is an extra argument, given at the start, which is a pointer
-        to  the compiled pattern. This is needed in order to gain access to the
+        to the compiled pattern. This is needed in order to gain access to  the
         name-to-number translation table.
-        These functions call pcre_get_stringnumber(), and if it succeeds,  they
+        These  functions call pcre_get_stringnumber(), and if it succeeds, they
-        then  call  pcre_copy_substring() or pcre_get_substring(), as appropri-
+        then call pcre_copy_substring() or pcre_get_substring(),  as  appropri-
-        ate. NOTE: If PCRE_DUPNAMES is set and there are duplicate  names,  the
+        ate.  NOTE:  If PCRE_DUPNAMES is set and there are duplicate names, the
         behaviour may not be what you want (see the next section).
-Line 2177 
 DUPLICATE SUBPATTERN NAMES
+Line 2352 
 DUPLICATE SUBPATTERN NAMES
         int pcre_get_stringtable_entries(const pcre *code,
              const char *name, char **first, char **last);
-        When  a  pattern  is  compiled with the PCRE_DUPNAMES option, names for
+        When a pattern is compiled with the  PCRE_DUPNAMES  option,  names  for
-        subpatterns are not required to  be  unique.  Normally,  patterns  with
+        subpatterns  are  not  required  to  be unique. Normally, patterns with
-        duplicate  names  are such that in any one match, only one of the named
+        duplicate names are such that in any one match, only one of  the  named
-        subpatterns participates. An example is shown in the pcrepattern  docu-
+        subpatterns  participates. An example is shown in the pcrepattern docu-
-        mentation. When duplicates are present, pcre_copy_named_substring() and
+        mentation.
-        pcre_get_named_substring() return the first substring corresponding  to
-        the  given  name  that  is  set.  If  none  are set, an empty string is
-        returned.  The pcre_get_stringnumber() function returns one of the num-
-        bers  that are associated with the name, but it is not defined which it
-        is.
-        If you want to get full details of all captured substrings for a  given
+        When   duplicates   are   present,   pcre_copy_named_substring()    and
-        name,  you  must  use  the pcre_get_stringtable_entries() function. The
+        pcre_get_named_substring()  return the first substring corresponding to
+        the given name that is set. If  none  are  set,  PCRE_ERROR_NOSUBSTRING
+        (-7)  is  returned;  no  data  is returned. The pcre_get_stringnumber()
+        function returns one of the numbers that are associated with the  name,
+        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
         first argument is the compiled pattern, and the second is the name. The
-        third  and  fourth  are  pointers to variables which are updated by the
+        third and fourth are pointers to variables which  are  updated  by  the
         function. After it has run, they point to the first and last entries in
-        the  name-to-number  table  for  the  given  name.  The function itself
+        the name-to-number table  for  the  given  name.  The  function  itself
-        returns the length of each entry,  or  PCRE_ERROR_NOSUBSTRING  (-7)  if
+        returns  the  length  of  each entry, or PCRE_ERROR_NOSUBSTRING (-7) if
-        there  are none. The format of the table is described above in the sec-
+        there are none. The format of the table is described above in the  sec-
-        tion entitled Information about a  pattern.   Given  all  the  relevant
+        tion  entitled  Information  about  a  pattern.  Given all the relevant
-        entries  for the name, you can extract each of their numbers, and hence
+        entries for the name, you can extract each of their numbers, and  hence
         the captured data, if any.
  FINDING ALL POSSIBLE MATCHES
-        The traditional matching function uses a  similar  algorithm  to  Perl,
+        The  traditional  matching  function  uses a similar algorithm to Perl,
         which stops when it finds the first match, starting at a given point in
-        the subject. If you want to find all possible matches, or  the  longest
+        the  subject.  If you want to find all possible matches, or the longest
-        possible  match,  consider using the alternative matching function (see
+        possible match, consider using the alternative matching  function  (see
-        below) instead. If you cannot use the alternative function,  but  still
+        below)  instead.  If you cannot use the alternative function, but still
-        need  to  find all possible matches, you can kludge it up by making use
+        need to find all possible matches, you can kludge it up by  making  use
         of the callout facility, which is described in the pcrecallout documen-
         tation.
         What you have to do is to insert a callout right at the end of the pat-
-        tern.  When your callout function is called, extract and save the  cur-
+        tern.   When your callout function is called, extract and save the cur-
-        rent  matched  substring.  Then  return  1, which forces pcre_exec() to
+        rent matched substring. Then return  1,  which  forces  pcre_exec()  to
-        backtrack and try other alternatives. Ultimately, when it runs  out  of
+        backtrack  and  try other alternatives. Ultimately, when it runs out of
         matches, pcre_exec() will yield PCRE_ERROR_NOMATCH.
-Line 2226 
 MATCHING A PATTERN: THE ALTERNATIVE FUNC
+Line 2403 
 MATCHING A PATTERN: THE ALTERNATIVE FUNC
              int options, int *ovector, int ovecsize,
              int *workspace, int wscount);
-        The  function  pcre_dfa_exec()  is  called  to  match  a subject string
+        The function pcre_dfa_exec()  is  called  to  match  a  subject  string
-        against a compiled pattern, using a matching algorithm that  scans  the
+        against  a  compiled pattern, using a matching algorithm that scans the
-        subject  string  just  once, and does not backtrack. This has different
+        subject string just once, and does not backtrack.  This  has  different
-        characteristics to the normal algorithm, and  is  not  compatible  with
+        characteristics  to  the  normal  algorithm, and is not compatible with
-        Perl.  Some  of the features of PCRE patterns are not supported. Never-
+        Perl. Some of the features of PCRE patterns are not  supported.  Never-
-        theless, there are times when this kind of matching can be useful.  For
+        theless,  there are times when this kind of matching can be useful. For
         a discussion of the two matching algorithms, see the pcrematching docu-
         mentation.
-        The arguments for the pcre_dfa_exec() function  are  the  same  as  for
+        The  arguments  for  the  pcre_dfa_exec()  function are the same as for
         pcre_exec(), plus two extras. The ovector argument is used in a differ-
-        ent way, and this is described below. The other  common  arguments  are
+        ent  way,  and  this is described below. The other common arguments are
-        used  in  the  same way as for pcre_exec(), so their description is not
+        used in the same way as for pcre_exec(), so their  description  is  not
         repeated here.
-        The two additional arguments provide workspace for  the  function.  The
+        The  two  additional  arguments provide workspace for the function. The
-        workspace  vector  should  contain at least 20 elements. It is used for
+        workspace vector should contain at least 20 elements. It  is  used  for
         keeping  track  of  multiple  paths  through  the  pattern  tree.  More
-        workspace  will  be  needed for patterns and subjects where there are a
+        workspace will be needed for patterns and subjects where  there  are  a
         lot of potential matches.
         Here is an example of a simple call to pcre_dfa_exec():
-Line 2266 
 MATCHING A PATTERN: THE ALTERNATIVE FUNC
+Line 2443 
 MATCHING A PATTERN: THE ALTERNATIVE FUNC
     Option bits for pcre_dfa_exec()
-        The unused bits of the options argument  for  pcre_dfa_exec()  must  be
+        The  unused  bits  of  the options argument for pcre_dfa_exec() must be
-        zero.  The  only  bits  that  may  be  set are PCRE_ANCHORED, PCRE_NEW-
+        zero. The only bits  that  may  be  set  are  PCRE_ANCHORED,  PCRE_NEW-
-        LINE_xxx, PCRE_NOTBOL, PCRE_NOTEOL, PCRE_NOTEMPTY,  PCRE_NO_UTF8_CHECK,
+        LINE_xxx,  PCRE_NOTBOL, PCRE_NOTEOL, PCRE_NOTEMPTY, PCRE_NO_UTF8_CHECK,
         PCRE_PARTIAL, PCRE_DFA_SHORTEST, and PCRE_DFA_RESTART. All but the last
         three of these are the same as for pcre_exec(), so their description is
         not repeated here.
           PCRE_PARTIAL
-        This  has  the  same general effect as it does for pcre_exec(), but the
+        This has the same general effect as it does for  pcre_exec(),  but  the
-        details  are  slightly  different.  When  PCRE_PARTIAL   is   set   for
+        details   are   slightly   different.  When  PCRE_PARTIAL  is  set  for
-        pcre_dfa_exec(),  the  return code PCRE_ERROR_NOMATCH is converted into
+        pcre_dfa_exec(), the return code PCRE_ERROR_NOMATCH is  converted  into
-        PCRE_ERROR_PARTIAL if the end of the subject  is  reached,  there  have
+        PCRE_ERROR_PARTIAL  if  the  end  of the subject is reached, there have
         been no complete matches, but there is still at least one matching pos-
-        sibility. The portion of the string that provided the partial match  is
+        sibility.  The portion of the string that provided the partial match is
         set as the first matching string.
           PCRE_DFA_SHORTEST
-        Setting  the  PCRE_DFA_SHORTEST option causes the matching algorithm to
+        Setting the PCRE_DFA_SHORTEST option causes the matching  algorithm  to
         stop as soon as it has found one match. Because of the way the alterna-
-        tive  algorithm  works, this is necessarily the shortest possible match
+        tive algorithm works, this is necessarily the shortest  possible  match
         at the first possible matching point in the subject string.
           PCRE_DFA_RESTART
-        When pcre_dfa_exec()  is  called  with  the  PCRE_PARTIAL  option,  and
+        When  pcre_dfa_exec()  is  called  with  the  PCRE_PARTIAL  option, and
-        returns  a  partial  match, it is possible to call it again, with addi-
+        returns a partial match, it is possible to call it  again,  with  addi-
-        tional subject characters, and have it continue with  the  same  match.
+        tional  subject  characters,  and have it continue with the same match.
-        The  PCRE_DFA_RESTART  option requests this action; when it is set, the
+        The PCRE_DFA_RESTART option requests this action; when it is  set,  the
-        workspace and wscount options must reference the same vector as  before
+        workspace  and wscount options must reference the same vector as before
-        because  data  about  the  match so far is left in them after a partial
+        because data about the match so far is left in  them  after  a  partial
-        match. There is more discussion of this  facility  in  the  pcrepartial
+        match.  There  is  more  discussion of this facility in the pcrepartial
         documentation.
     Successful returns from pcre_dfa_exec()
-        When  pcre_dfa_exec()  succeeds, it may have matched more than one sub-
+        When pcre_dfa_exec() succeeds, it may have matched more than  one  sub-
         string in the subject. Note, however, that all the matches from one run
-        of  the  function  start  at the same point in the subject. The shorter
+        of the function start at the same point in  the  subject.  The  shorter
-        matches are all initial substrings of the longer matches. For  example,
+        matches  are all initial substrings of the longer matches. For example,
         if the pattern
           <.*>
-Line 2321 
 MATCHING A PATTERN: THE ALTERNATIVE FUNC
+Line 2498 
 MATCHING A PATTERN: THE ALTERNATIVE FUNC
           <something> <something else>
           <something> <something else> <something further>
-        On  success,  the  yield of the function is a number greater than zero,
+        On success, the yield of the function is a number  greater  than  zero,
-        which is the number of matched substrings.  The  substrings  themselves
+        which  is  the  number of matched substrings. The substrings themselves
-        are  returned  in  ovector. Each string uses two elements; the first is
+        are returned in ovector. Each string uses two elements;  the  first  is
-        the offset to the start, and the second is the offset to  the  end.  In
+        the  offset  to  the start, and the second is the offset to the end. In
-        fact,  all  the  strings  have the same start offset. (Space could have
+        fact, all the strings have the same start  offset.  (Space  could  have
-        been saved by giving this only once, but it was decided to retain  some
+        been  saved by giving this only once, but it was decided to retain some
-        compatibility  with  the  way pcre_exec() returns data, even though the
+        compatibility with the way pcre_exec() returns data,  even  though  the
         meaning of the strings is different.)
         The strings are returned in reverse order of length; that is, the long-
-        est  matching  string is given first. If there were too many matches to
+        est matching string is given first. If there were too many  matches  to
-        fit into ovector, the yield of the function is zero, and the vector  is
+        fit  into ovector, the yield of the function is zero, and the vector is
         filled with the longest matches.
     Error returns from pcre_dfa_exec()
-        The  pcre_dfa_exec()  function returns a negative number when it fails.
+        The pcre_dfa_exec() function returns a negative number when  it  fails.
-        Many of the errors are the same  as  for  pcre_exec(),  and  these  are
+        Many  of  the  errors  are  the  same as for pcre_exec(), and these are
-        described  above.   There are in addition the following errors that are
+        described above.  There are in addition the following errors  that  are
         specific to pcre_dfa_exec():
           PCRE_ERROR_DFA_UITEM      (-16)
-        This return is given if pcre_dfa_exec() encounters an item in the  pat-
+        This  return is given if pcre_dfa_exec() encounters an item in the pat-
-        tern  that  it  does not support, for instance, the use of \C or a back
+        tern that it does not support, for instance, the use of \C  or  a  back
         reference.
           PCRE_ERROR_DFA_UCOND      (-17)
-        This return is given if pcre_dfa_exec()  encounters  a  condition  item
+        This  return  is  given  if pcre_dfa_exec() encounters a condition item
-        that  uses  a back reference for the condition, or a test for recursion
+        that uses a back reference for the condition, or a test  for  recursion
         in a specific group. These are not supported.
           PCRE_ERROR_DFA_UMLIMIT    (-18)
-        This return is given if pcre_dfa_exec() is called with an  extra  block
+        This  return  is given if pcre_dfa_exec() is called with an extra block
         that contains a setting of the match_limit field. This is not supported
         (it is meaningless).
           PCRE_ERROR_DFA_WSSIZE     (-19)
-        This return is given if  pcre_dfa_exec()  runs  out  of  space  in  the
+        This  return  is  given  if  pcre_dfa_exec()  runs  out of space in the
         workspace vector.
           PCRE_ERROR_DFA_RECURSE    (-20)
-        When  a  recursive subpattern is processed, the matching function calls
+        When a recursive subpattern is processed, the matching  function  calls
-        itself recursively, using private vectors for  ovector  and  workspace.
+        itself  recursively,  using  private vectors for ovector and workspace.
-        This  error  is  given  if  the output vector is not large enough. This
+        This error is given if the output vector  is  not  large  enough.  This
         should be extremely rare, as a vector of size 1000 is used.
  SEE ALSO
-        pcrebuild(3), pcrecallout(3), pcrecpp(3)(3), pcrematching(3),  pcrepar-
+        pcrebuild(3),  pcrecallout(3), pcrecpp(3)(3), pcrematching(3), pcrepar-
-        tial(3),  pcreposix(3), pcreprecompile(3), pcresample(3), pcrestack(3).
+        tial(3), pcreposix(3), pcreprecompile(3), pcresample(3),  pcrestack(3).
  AUTHOR
-Line 2388 
 AUTHOR
+Line 2565 
 AUTHOR
  REVISION
-        Last updated: 24 April 2007
+        Last updated: 26 December 2007
         Copyright (c) 1997-2007 University of Cambridge.
  ------------------------------------------------------------------------------
-Line 2491 
 THE CALLOUT INTERFACE
+Line 2668 
 THE CALLOUT INTERFACE
         The subject and subject_length fields contain copies of the values that
         were passed to pcre_exec().
-        The start_match field contains the offset within the subject  at  which
+        The start_match field normally contains the offset within  the  subject
-        the  current match attempt started. If the pattern is not anchored, the
+        at  which  the  current  match  attempt started. However, if the escape
-        callout function may be called several times from the same point in the
+        sequence \K has been encountered, this value is changed to reflect  the
-        pattern for different starting points in the subject.
+        modified  starting  point.  If the pattern is not anchored, the callout
+        function may be called several times from the same point in the pattern
+        for different starting points in the subject.
         The  current_position  field  contains the offset within the subject of
         the current match pointer.
-Line 2557 
 AUTHOR
+Line 2736 
 AUTHOR
  REVISION
-        Last updated: 06 March 2007
+        Last updated: 29 May 2007
         Copyright (c) 1997-2007 University of Cambridge.
  ------------------------------------------------------------------------------
-Line 2573 
 DIFFERENCES BETWEEN PCRE AND PERL
+Line 2752 
 DIFFERENCES BETWEEN PCRE AND PERL
         This  document describes the differences in the ways that PCRE and Perl
         handle regular expressions. The differences described here  are  mainly
-        with  respect  to  Perl 5.8, though PCRE version 7.0 contains some fea-
+        with  respect  to  Perl 5.8, though PCRE versions 7.0 and later contain
-        tures that are expected to be in the forthcoming Perl 5.10.
+        some features that are expected to be in the forthcoming Perl 5.10.
 . PCRE has only a subset of Perl's UTF-8 and Unicode support.  Details
         of  what  it does have are given in the section on UTF-8 support in the
-Line 2639 
 DIFFERENCES BETWEEN PCRE AND PERL
+Line 2818 
 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 2652 
 DIFFERENCES BETWEEN PCRE AND PERL
+Line 2837 
 DIFFERENCES BETWEEN PCRE AND PERL
         meta-character matches only at the very end of the string.
         (c) If PCRE_EXTRA is set, a backslash followed by a letter with no spe-
-        cial  meaning  is  faulted.  Otherwise,  like  Perl,  the  backslash is
+        cial meaning is faulted. Otherwise, like Perl, the backslash is quietly
-        ignored. (Perl can be made to issue a warning.)
+        ignored.  (Perl can be made to issue a warning.)
         (d) If PCRE_UNGREEDY is set, the greediness of the  repetition  quanti-
         fiers is inverted, that is, by default they are not greedy, but if fol-
-Line 2665 
 DIFFERENCES BETWEEN PCRE AND PERL
+Line 2850 
 DIFFERENCES BETWEEN PCRE AND PERL
         (f)  The PCRE_NOTBOL, PCRE_NOTEOL, PCRE_NOTEMPTY, and PCRE_NO_AUTO_CAP-
         TURE options for pcre_exec() have no Perl equivalents.
-        (g) The callout facility is PCRE-specific.
+        (g) The \R escape sequence can be restricted to match only CR,  LF,  or
+        CRLF by the PCRE_BSR_ANYCRLF option.
+        (h) The callout facility is PCRE-specific.
-        (h) The partial matching facility is PCRE-specific.
+        (i) The partial matching facility is PCRE-specific.
-        (i) Patterns compiled by PCRE can be saved and re-used at a later time,
+        (j) Patterns compiled by PCRE can be saved and re-used at a later time,
         even on different hosts that have the other endianness.
-        (j)  The  alternative  matching function (pcre_dfa_exec()) matches in a
+        (k) The alternative matching function (pcre_dfa_exec())  matches  in  a
         different way and is not Perl-compatible.
+        (l)  PCRE  recognizes some special sequences such as (*CR) at the start
+        of a pattern that set overall options that cannot be changed within the
+        pattern.
  AUTHOR
-Line 2685 
 AUTHOR
+Line 2877 
 AUTHOR
  REVISION
-        Last updated: 06 March 2007
+        Last updated: 11 September 2007
         Copyright (c) 1997-2007 University of Cambridge.
  ------------------------------------------------------------------------------
-Line 2699 
 NAME
+Line 2891 
 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 2718 
 PCRE REGULAR EXPRESSION DETAILS
+Line 2912 
 PCRE REGULAR EXPRESSION DETAILS
         ported  by  PCRE when its main matching function, pcre_exec(), is used.
         From  release  6.0,   PCRE   offers   a   second   matching   function,
         pcre_dfa_exec(),  which matches using a different algorithm that is not
-        Perl-compatible. The advantages and disadvantages  of  the  alternative
+        Perl-compatible. Some of the features discussed below are not available
-        function, and how it differs from the normal function, are discussed in
+        when  pcre_dfa_exec()  is used. The advantages and disadvantages of the
-        the pcrematching page.
+        alternative function, and how it differs from the normal function,  are
+        discussed in the pcrematching page.
+ NEWLINE CONVENTIONS
+        PCRE  supports five different conventions for indicating line breaks in
+        strings: a single CR (carriage return) character, a  single  LF  (line-
+        feed) character, the two-character sequence CRLF, any of the three pre-
+        ceding, or any Unicode newline sequence. The pcreapi page  has  further
+        discussion  about newlines, and shows how to set the newline convention
+        in the options arguments for the compiling and matching functions.
+        It is also possible to specify a newline convention by starting a  pat-
+        tern string with one of the following five sequences:
+          (*CR)        carriage return
+          (*LF)        linefeed
+          (*CRLF)      carriage return, followed by linefeed
+          (*ANYCRLF)   any of the three above
+          (*ANY)       all Unicode newline sequences
+        These override the default and the options given to pcre_compile(). For
+        example, on a Unix system where LF is the default newline sequence, the
+        pattern
+          (*CR)a.b
+        changes the convention to CR. That pattern matches "a\nb" because LF is
+        no longer a newline. Note that these special settings,  which  are  not
+        Perl-compatible,  are  recognized  only at the very start of a pattern,
+        and that they must be in upper case.  If  more  than  one  of  them  is
+        present, the last one is used.
+        The  newline  convention  does  not  affect what the \R escape sequence
+        matches. By default, this is any Unicode  newline  sequence,  for  Perl
+        compatibility.  However, this can be changed; see the description of \R
+        in the section entitled "Newline sequences" below. A change of \R  set-
+        ting can be combined with a change of newline convention.
  CHARACTERS AND METACHARACTERS
-        A regular expression is a pattern that is  matched  against  a  subject
+        A  regular  expression  is  a pattern that is matched against a subject
-        string  from  left  to right. Most characters stand for themselves in a
+        string from left to right. Most characters stand for  themselves  in  a
-        pattern, and match the corresponding characters in the  subject.  As  a
+        pattern,  and  match  the corresponding characters in the subject. As a
         trivial example, the pattern
           The quick brown fox
         matches a portion of a subject string that is identical to itself. When
-        caseless matching is specified (the PCRE_CASELESS option), letters  are
+        caseless  matching is specified (the PCRE_CASELESS option), letters are
-        matched  independently  of case. In UTF-8 mode, PCRE always understands
+        matched independently of case. In UTF-8 mode, PCRE  always  understands
-        the concept of case for characters whose values are less than  128,  so
+        the  concept  of case for characters whose values are less than 128, so
-        caseless  matching  is always possible. For characters with higher val-
+        caseless matching is always possible. For characters with  higher  val-
-        ues, the concept of case is supported if PCRE is compiled with  Unicode
+        ues,  the concept of case is supported if PCRE is compiled with Unicode
-        property  support,  but  not  otherwise.   If  you want to use caseless
+        property support, but not otherwise.   If  you  want  to  use  caseless
-        matching for characters 128 and above, you must  ensure  that  PCRE  is
+        matching  for  characters  128  and above, you must ensure that PCRE is
         compiled with Unicode property support as well as with UTF-8 support.
-        The  power  of  regular  expressions  comes from the ability to include
+        The power of regular expressions comes  from  the  ability  to  include
-        alternatives and repetitions in the pattern. These are encoded  in  the
+        alternatives  and  repetitions in the pattern. These are encoded in the
         pattern by the use of metacharacters, which do not stand for themselves
         but instead are interpreted in some special way.
-        There are two different sets of metacharacters: those that  are  recog-
+        There  are  two different sets of metacharacters: those that are recog-
-        nized  anywhere in the pattern except within square brackets, and those
+        nized anywhere in the pattern except within square brackets, and  those
-        that are recognized within square brackets.  Outside  square  brackets,
+        that  are  recognized  within square brackets. Outside square brackets,
         the metacharacters are as follows:
           \      general escape character with several uses
-Line 2768 
 CHARACTERS AND METACHARACTERS
+Line 3000 
 CHARACTERS AND METACHARACTERS
                  also "possessive quantifier"
           {      start min/max quantifier
-        Part  of  a  pattern  that is in square brackets is called a "character
+        Part of a pattern that is in square brackets  is  called  a  "character
         class". In a character class the only metacharacters are:
           \      general escape character
-Line 2778 
 CHARACTERS AND METACHARACTERS
+Line 3010 
 CHARACTERS AND METACHARACTERS
                    syntax)
           ]      terminates the character class
-        The following sections describe the use of each of the  metacharacters.
+        The  following sections describe the use of each of the metacharacters.
  BACKSLASH
         The backslash character has several uses. Firstly, if it is followed by
-        a non-alphanumeric character, it takes away any  special  meaning  that
+        a  non-alphanumeric  character,  it takes away any special meaning that
-        character  may  have.  This  use  of  backslash  as an escape character
+        character may have. This  use  of  backslash  as  an  escape  character
         applies both inside and outside character classes.
-        For example, if you want to match a * character, you write  \*  in  the
+        For  example,  if  you want to match a * character, you write \* in the
-        pattern.   This  escaping  action  applies whether or not the following
+        pattern.  This escaping action applies whether  or  not  the  following
-        character would otherwise be interpreted as a metacharacter, so  it  is
+        character  would  otherwise be interpreted as a metacharacter, so it is
-        always  safe  to  precede  a non-alphanumeric with backslash to specify
+        always safe to precede a non-alphanumeric  with  backslash  to  specify
-        that it stands for itself. In particular, if you want to match a  back-
+        that  it stands for itself. In particular, if you want to match a back-
         slash, you write \\.
-        If  a  pattern is compiled with the PCRE_EXTENDED option, whitespace in
+        If a pattern is compiled with the PCRE_EXTENDED option,  whitespace  in
-        the pattern (other than in a character class) and characters between  a
+        the  pattern (other than in a character class) and characters between a
         # outside a character class and the next newline are ignored. An escap-
-        ing backslash can be used to include a whitespace  or  #  character  as
+        ing  backslash  can  be  used to include a whitespace or # character as
         part of the pattern.
-        If  you  want  to remove the special meaning from a sequence of charac-
+        If you want to remove the special meaning from a  sequence  of  charac-
-        ters, you can do so by putting them between \Q and \E. This is  differ-
+        ters,  you can do so by putting them between \Q and \E. This is differ-
-        ent  from  Perl  in  that  $  and  @ are handled as literals in \Q...\E
+        ent from Perl in that $ and  @  are  handled  as  literals  in  \Q...\E
-        sequences in PCRE, whereas in Perl, $ and @ cause  variable  interpola-
+        sequences  in  PCRE, whereas in Perl, $ and @ cause variable interpola-
         tion. Note the following examples:
           Pattern            PCRE matches   Perl matches
-Line 2814 
 BACKSLASH
+Line 3046 
 BACKSLASH
           \Qabc\$xyz\E       abc\$xyz       abc\$xyz
           \Qabc\E\$\Qxyz\E   abc$xyz        abc$xyz
-        The  \Q...\E  sequence  is recognized both inside and outside character
+        The \Q...\E sequence is recognized both inside  and  outside  character
         classes.
     Non-printing characters
         A second use of backslash provides a way of encoding non-printing char-
-        acters  in patterns in a visible manner. There is no restriction on the
+        acters in patterns in a visible manner. There is no restriction on  the
-        appearance of non-printing characters, apart from the binary zero  that
+        appearance  of non-printing characters, apart from the binary zero that
-        terminates  a  pattern,  but  when  a pattern is being prepared by text
+        terminates a pattern, but when a pattern  is  being  prepared  by  text
-        editing, it is usually easier  to  use  one  of  the  following  escape
+        editing,  it  is  usually  easier  to  use  one of the following escape
         sequences than the binary character it represents:
           \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)
+          \n        linefeed (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..
-        The  precise  effect of \cx is as follows: if x is a lower case letter,
+        The precise effect of \cx is as follows: if x is a lower  case  letter,
-        it is converted to upper case. Then bit 6 of the character (hex 40)  is
+        it  is converted to upper case. Then bit 6 of the character (hex 40) is
-        inverted.   Thus  \cz becomes hex 1A, but \c{ becomes hex 3B, while \c;
+        inverted.  Thus \cz becomes hex 1A, but \c{ becomes hex 3B,  while  \c;
         becomes hex 7B.
-        After \x, from zero to two hexadecimal digits are read (letters can  be
+        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
+        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
+        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-
-Line 2905 
 BACKSLASH
+Line 3140 
 BACKSLASH
     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. Back
+        ally  enclosed  in braces, is an absolute or relative back reference. A
-        references are discussed later, following the discussion  of  parenthe-
+        named back reference can be coded as \g{name}. Back references are dis-
-        sized subpatterns.
+        cussed later, following the discussion of parenthesized subpatterns.
     Generic character types
-Line 2917 
 BACKSLASH
+Line 3152 
 BACKSLASH
           \d     any decimal digit
           \D     any character that is not a decimal digit
+          \h     any horizontal whitespace character
+          \H     any character that is not a horizontal whitespace character
           \s     any whitespace character
           \S     any character that is not a whitespace character
+          \v     any vertical whitespace character
+          \V     any character that is not a vertical whitespace character
           \w     any "word" character
           \W     any "non-word" character
-Line 2933 
 BACKSLASH
+Line 3172 
 BACKSLASH
         For  compatibility  with Perl, \s does not match the VT character (code
 ).  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.)
+        ter. In PCRE, it never does.
+        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
+        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
+        UTF-8 mode.  The horizontal space characters are:
+          U+0009     Horizontal tab
+          U+0020     Space
+          U+00A0     Non-break space
+          U+1680     Ogham space mark
+          U+180E     Mongolian vowel separator
+          U+2000     En quad
+          U+2001     Em quad
+          U+2002     En space
+          U+2003     Em space
+          U+2004     Three-per-em space
+          U+2005     Four-per-em space
+          U+2006     Six-per-em space
+          U+2007     Figure space
+          U+2008     Punctuation space
+          U+2009     Thin space
+          U+200A     Hair space
+          U+202F     Narrow no-break space
+          U+205F     Medium mathematical space
+          U+3000     Ideographic space
+        The vertical space characters are:
+          U+000A     Linefeed
+          U+000B     Vertical tab
+          U+000C     Formfeed
+          U+000D     Carriage return
+          U+0085     Next line
+          U+2028     Line separator
+          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-
-Line 2943 
 BACKSLASH
+Line 3222 
 BACKSLASH
         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
         systems, or "french" in Windows, some character codes greater than  128
-        are used for accented letters, and these are matched by \w.
+        are  used for accented letters, and these are matched by \w. The use of
+        locales with Unicode is discouraged.
-        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. 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, by default, the escape sequence  \R  matches
-        newline sequence. This is an extension to Perl. In non-UTF-8 mode \R is
+        any Unicode newline sequence. This is a Perl 5.10 feature. In non-UTF-8
-        equivalent to the following:
+        mode \R is equivalent to the following:
           (?>\r\n|\n|\x0b|\f|\r|\x85)
-Line 2970 
 BACKSLASH
+Line 3245 
 BACKSLASH
         rator,  U+2029).   Unicode character property support is not needed for
         these characters to be recognized.
+        It is possible to restrict \R to match only CR, LF, or CRLF (instead of
+        the  complete  set  of  Unicode  line  endings)  by  setting the option
+        PCRE_BSR_ANYCRLF either at compile time or when the pattern is matched.
+        (BSR is an abbrevation for "backslash R".) This can be made the default
+        when PCRE is built; if this is the case, the  other  behaviour  can  be
+        requested  via  the  PCRE_BSR_UNICODE  option.   It is also possible to
+        specify these settings by starting a pattern string  with  one  of  the
+        following sequences:
+          (*BSR_ANYCRLF)   CR, LF, or CRLF only
+          (*BSR_UNICODE)   any Unicode newline sequence
+        These override the default and the options given to pcre_compile(), but
+        they can be overridden by options given to pcre_exec(). Note that these
+        special settings, which are not Perl-compatible, are recognized only at
+        the very start of a pattern, and that they must be in  upper  case.  If
+        more  than  one  of  them is present, the last one is used. They can be
+        combined with a change of newline convention, for  example,  a  pattern
+        can start with:
+          (*ANY)(*BSR_ANYCRLF)
         Inside a character class, \R matches the letter "R".
     Unicode character properties
         When PCRE is built with Unicode character property support, three addi-
-        tional  escape  sequences  to  match character properties are available
+        tional escape sequences that match characters with specific  properties
-        when UTF-8 mode is selected. They are:
+        are  available.   When not in UTF-8 mode, these sequences are of course
+        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 3067 
 BACKSLASH
+Line 3366 
 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
+        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
+        sequence. For example, the pattern:
+          foo\Kbar
+        matches "foobar", but reports that it has matched "bar".  This  feature
+        is  similar  to  a lookbehind assertion (described below).  However, in
+        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
+        not interfere with the setting of captured  substrings.   For  example,
+        when the pattern
+          (foo)\Kbar
+        matches "foobar", the first substring is still set to "foo".
     Simple assertions
         The  final use of backslash is for certain simple assertions. An asser-
-Line 3396 
 VERTICAL BAR
+Line 3722 
 VERTICAL BAR
  INTERNAL OPTION SETTING
         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 (which are Perl-compatible) can be  changed  from
-        sequence  of  Perl  option  letters  enclosed between "(?" and ")". The
+        within  the  pattern  by  a  sequence  of  Perl option letters enclosed
-        option letters are
+        between "(?" and ")".  The option letters are
           i  for PCRE_CASELESS
           m  for PCRE_MULTILINE
-Line 3412 
 INTERNAL OPTION SETTING
+Line 3738 
 INTERNAL OPTION SETTING
         is also permitted. If a  letter  appears  both  before  and  after  the
         hyphen, the option is unset.
+        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
+        the characters J, U and X respectively.
         When  an option change occurs at top level (that is, not inside subpat-
         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,
-Line 3437 
 INTERNAL OPTION SETTING
+Line 3767 
 INTERNAL OPTION SETTING
         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
+        Note: There are other PCRE-specific options that  can  be  set  by  the
-        can  be changed in the same way as the Perl-compatible options by using
+        application  when  the  compile  or match functions are called. In some
-        the characters J, U and X respectively.
+        cases the pattern can contain special  leading  sequences  to  override
+        what  the  application  has set or what has been defaulted. Details are
+        given in the section entitled "Newline sequences" above.
  SUBPATTERNS
-Line 3497 
 SUBPATTERNS
+Line 3829 
 SUBPATTERNS
         "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
+        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-
+        turing  parentheses  are  numbered one. Thus, when the pattern matches,
+        you can look at captured substring number  one,  whichever  alternative
+        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
+        each branch. The numbers of any capturing buffers that follow the  sub-
+        pattern  start after the highest number used in any branch. The follow-
+        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
+        refers to the first one in the pattern with the given number.
+        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
-Line 3536 
 NAMED SUBPATTERNS
+Line 3899 
 NAMED SUBPATTERNS
           (?<DN>Sat)(?:urday)?
         There  are  five capturing substrings, but only one is ever set after a
-        match.  The convenience  function  for  extracting  the  data  by  name
+        match.  (An alternative way of solving this problem is to use a "branch
-        returns  the  substring  for  the first (and in this example, the only)
+        reset" subpattern, as described in the previous section.)
-        subpattern of that name that matched.  This  saves  searching  to  find
-        which  numbered  subpattern  it  was. If you make a reference to a non-
+        The  convenience  function  for extracting the data by name returns the
-        unique named subpattern from elsewhere in the  pattern,  the  one  that
+        substring for the first (and in this example, the only)  subpattern  of
-        corresponds  to  the  lowest number is used. For further details of the
+        that  name  that  matched.  This saves searching to find which numbered
-        interfaces for handling named subpatterns, see the  pcreapi  documenta-
+        subpattern it was. If you make a reference to a non-unique  named  sub-
-        tion.
+        pattern  from elsewhere in the pattern, the one that corresponds to the
+        lowest number is used. For further details of the interfaces  for  han-
+        dling named subpatterns, see the pcreapi documentation.
  REPETITION
-Line 3748 
 ATOMIC GROUPING AND POSSESSIVE QUANTIFIE
+Line 4113 
 ATOMIC GROUPING AND POSSESSIVE QUANTIFIE
           \d++foo
-        Possessive  quantifiers  are  always  greedy;  the   setting   of   the
+        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
+        simpler  forms  of atomic group. However, there is no difference in the
-        meaning  of  a  possessive  quantifier and the equivalent atomic group,
+        meaning of a possessive quantifier and  the  equivalent  atomic  group,
-        though there may be a performance  difference;  possessive  quantifiers
+        though  there  may  be a performance difference; possessive quantifiers
         should be slightly faster.
-        The  possessive  quantifier syntax is an extension to the Perl 5.8 syn-
+        The possessive quantifier syntax is an extension to the Perl  5.8  syn-
-        tax.  Jeffrey Friedl originated the idea (and the name)  in  the  first
+        tax.   Jeffrey  Friedl  originated the idea (and the name) in the first
         edition of his book. Mike McCloskey liked it, so implemented it when he
-        built Sun's Java package, and PCRE copied it from there. It  ultimately
+        built  Sun's Java package, and PCRE copied it from there. It ultimately
         found its way into Perl at release 5.10.
         PCRE has an optimization that automatically "possessifies" certain sim-
-        ple pattern constructs. For example, the sequence  A+B  is  treated  as
+        ple  pattern  constructs.  For  example, the sequence A+B is treated as
-        A++B  because  there is no point in backtracking into a sequence of A's
+        A++B because there is no point in backtracking into a sequence  of  A's
         when B must follow.
-        When a pattern contains an unlimited repeat inside  a  subpattern  that
+        When  a  pattern  contains an unlimited repeat inside a subpattern that
-        can  itself  be  repeated  an  unlimited number of times, the use of an
+        can itself be repeated an unlimited number of  times,  the  use  of  an
-        atomic group is the only way to avoid some  failing  matches  taking  a
+        atomic  group  is  the  only way to avoid some failing matches taking a
         very long time indeed. The pattern
           (\D+|<\d+>)*[!?]
-        matches  an  unlimited number of substrings that either consist of non-
+        matches an unlimited number of substrings that either consist  of  non-
-        digits, or digits enclosed in <>, followed by either ! or  ?.  When  it
+        digits,  or  digits  enclosed in <>, followed by either ! or ?. When it
         matches, it runs quickly. However, if it is applied to
           aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
-        it  takes  a  long  time  before reporting failure. This is because the
+        it takes a long time before reporting  failure.  This  is  because  the
-        string can be divided between the internal \D+ repeat and the  external
+        string  can be divided between the internal \D+ repeat and the external
-        *  repeat  in  a  large  number of ways, and all have to be tried. (The
+        * repeat in a large number of ways, and all  have  to  be  tried.  (The
-        example uses [!?] rather than a single character at  the  end,  because
+        example  uses  [!?]  rather than a single character at the end, because
-        both  PCRE  and  Perl have an optimization that allows for fast failure
+        both PCRE and Perl have an optimization that allows  for  fast  failure
-        when a single character is used. They remember the last single  charac-
+        when  a single character is used. They remember the last single charac-
-        ter  that  is required for a match, and fail early if it is not present
+        ter that is required for a match, and fail early if it is  not  present
-        in the string.) If the pattern is changed so that  it  uses  an  atomic
+        in  the  string.)  If  the pattern is changed so that it uses an atomic
         group, like this:
           ((?>\D+)|<\d+>)*[!?]
-        sequences  of non-digits cannot be broken, and failure happens quickly.
+        sequences of non-digits cannot be broken, and failure happens  quickly.
  BACK REFERENCES
         Outside a character class, a backslash followed by a digit greater than
 (and possibly further digits) is a back reference to a capturing sub-
-        pattern earlier (that is, to its left) in the pattern,  provided  there
+        pattern  earlier  (that is, to its left) in the pattern, provided there
         have been that many previous capturing left parentheses.
         However, if the decimal number following the backslash is less than 10,
-        it is always taken as a back reference, and causes  an  error  only  if
+        it  is  always  taken  as a back reference, and causes an error only if
-        there  are  not that many capturing left parentheses in the entire pat-
+        there are not that many capturing left parentheses in the  entire  pat-
-        tern. In other words, the parentheses that are referenced need  not  be
+        tern.  In  other words, the parentheses that are referenced need not be
-        to  the left of the reference for numbers less than 10. A "forward back
+        to the left of the reference for numbers less than 10. A "forward  back
-        reference" of this type can make sense when a  repetition  is  involved
+        reference"  of  this  type can make sense when a repetition is involved
-        and  the  subpattern to the right has participated in an earlier itera-
+        and the subpattern to the right has participated in an  earlier  itera-
         tion.
-        It is not possible to have a numerical "forward back  reference"  to  a
+        It  is  not  possible to have a numerical "forward back reference" to a
-        subpattern  whose  number  is  10  or  more using this syntax because a
+        subpattern whose number is 10 or  more  using  this  syntax  because  a
-        sequence such as \50 is interpreted as a character  defined  in  octal.
+        sequence  such  as  \50 is interpreted as a character defined in octal.
         See the subsection entitled "Non-printing characters" above for further
-        details of the handling of digits following a backslash.  There  is  no
+        details  of  the  handling of digits following a backslash. There is no
-        such  problem  when named parentheses are used. A back reference to any
+        such problem when named parentheses are used. A back reference  to  any
         subpattern is possible using named parentheses (see below).
-        Another way of avoiding the ambiguity inherent in  the  use  of  digits
+        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:
           (abc(def)ghi)\g{-1}
         The sequence \g{-1} is a reference to the most recently started captur-
-        ing subpattern before \g, that is, is it equivalent to  \2.  Similarly,
+        ing  subpattern  before \g, that is, is it equivalent to \2. Similarly,
         \g{-2} would be equivalent to \1. The use of relative references can be
-        helpful in long patterns, and also in  patterns  that  are  created  by
+        helpful  in  long  patterns,  and  also in patterns that are created by
         joining together fragments that contain references within themselves.
-        A  back  reference matches whatever actually matched the capturing sub-
+        A back reference matches whatever actually matched the  capturing  sub-
-        pattern in the current subject string, rather  than  anything  matching
+        pattern  in  the  current subject string, rather than anything matching
         the subpattern itself (see "Subpatterns as subroutines" below for a way
         of doing that). So the pattern
           (sens|respons)e and \1ibility
-        matches "sense and sensibility" and "response and responsibility",  but
+        matches  "sense and sensibility" and "response and responsibility", but
-        not  "sense and responsibility". If caseful matching is in force at the
+        not "sense and responsibility". If caseful matching is in force at  the
-        time of the back reference, the case of letters is relevant. For  exam-
+        time  of the back reference, the case of letters is relevant. For exam-
         ple,
           ((?i)rah)\s+\1
-        matches  "rah  rah"  and  "RAH RAH", but not "RAH rah", even though the
+        matches "rah rah" and "RAH RAH", but not "RAH  rah",  even  though  the
         original capturing subpattern is matched caselessly.
-        Back references to named subpatterns use the Perl  syntax  \k<name>  or
+        There  are  several  different ways of writing back references to named
-        \k'name'  or  the  Python  syntax (?P=name). We could rewrite the above
+        subpatterns. The .NET syntax \k{name} and the Perl syntax  \k<name>  or
-        example in either of the following ways:
+        \k'name'  are supported, as is the Python syntax (?P=name). Perl 5.10's
+        unified back reference syntax, in which \g can be used for both numeric
+        and  named  references,  is  also supported. We could rewrite the above
+        example in any of the following ways:
           (?<p1>(?i)rah)\s+\k<p1>
+          (?'p1'(?i)rah)\s+\k{p1}
           (?P<p1>(?i)rah)\s+(?P=p1)
+          (?<p1>(?i)rah)\s+\g{p1}
         A subpattern that is referenced by  name  may  appear  in  the  pattern
         before or after the reference.
-Line 3978 
 ASSERTIONS
+Line 4353 
 ASSERTIONS
           (?<=abc|abde)
+        In some cases, the Perl 5.10 escape sequence \K (see above) can be used
+        instead  of  a lookbehind assertion; this is not restricted to a fixed-
+        length.
         The implementation of lookbehind assertions is, for  each  alternative,
         to  temporarily  move the current position back by the fixed length and
         then try to match. If there are insufficient characters before the cur-
-Line 4071 
 CONDITIONAL SUBPATTERNS
+Line 4450 
 CONDITIONAL SUBPATTERNS
         If  the  text between the parentheses consists of a sequence of digits,
         the condition is true if the capturing subpattern of  that  number  has
-        previously matched.
+        previously  matched.  An  alternative notation is to precede the digits
+        with a plus or minus sign. In this case, the subpattern number is rela-
+        tive rather than absolute.  The most recently opened parentheses can be
+        referenced by (?(-1), the next most recent by (?(-2),  and  so  on.  In
+        looping constructs it can also make sense to refer to subsequent groups
+        with constructs such as (?(+2).
-        Consider  the  following  pattern, which contains non-significant white
+        Consider the following pattern, which  contains  non-significant  white
         space to make it more readable (assume the PCRE_EXTENDED option) and to
         divide it into three parts for ease of discussion:
           ( \( )?    [^()]+    (?(1) \) )
-        The  first  part  matches  an optional opening parenthesis, and if that
+        The first part matches an optional opening  parenthesis,  and  if  that
         character is present, sets it as the first captured substring. The sec-
-        ond  part  matches one or more characters that are not parentheses. The
+        ond part matches one or more characters that are not  parentheses.  The
         third part is a conditional subpattern that tests whether the first set
         of parentheses matched or not. If they did, that is, if subject started
         with an opening parenthesis, the condition is true, and so the yes-pat-
-        tern  is  executed  and  a  closing parenthesis is required. Otherwise,
+        tern is executed and a  closing  parenthesis  is  required.  Otherwise,
-        since no-pattern is not present, the  subpattern  matches  nothing.  In
+        since  no-pattern  is  not  present, the subpattern matches nothing. In
-        other  words,  this  pattern  matches  a  sequence  of non-parentheses,
+        other words,  this  pattern  matches  a  sequence  of  non-parentheses,
         optionally enclosed in parentheses.
+        If  you  were  embedding  this pattern in a larger one, you could use a
+        relative reference:
+          ...other stuff... ( \( )?    [^()]+    (?(-1) \) ) ...
+        This makes the fragment independent of the parentheses  in  the  larger
+        pattern.
     Checking for a used subpattern by name
-        Perl uses the syntax (?(<name>)...) or (?('name')...)  to  test  for  a
+        Perl  uses  the  syntax  (?(<name>)...) or (?('name')...) to test for a
-        used  subpattern  by  name.  For compatibility with earlier versions of
+        used subpattern by name. For compatibility  with  earlier  versions  of
-        PCRE, which had this facility before Perl, the syntax  (?(name)...)  is
+        PCRE,  which  had this facility before Perl, the syntax (?(name)...) is
-        also  recognized. However, there is a possible ambiguity with this syn-
+        also recognized. However, there is a possible ambiguity with this  syn-
-        tax, because subpattern names may  consist  entirely  of  digits.  PCRE
+        tax,  because  subpattern  names  may  consist entirely of digits. PCRE
-        looks  first for a named subpattern; if it cannot find one and the name
+        looks first for a named subpattern; if it cannot find one and the  name
-        consists entirely of digits, PCRE looks for a subpattern of  that  num-
+        consists  entirely  of digits, PCRE looks for a subpattern of that num-
-        ber,  which must be greater than zero. Using subpattern names that con-
+        ber, which must be greater than zero. Using subpattern names that  con-
         sist entirely of digits is not recommended.
         Rewriting the above example to use a named subpattern gives this:
-Line 4110 
 CONDITIONAL SUBPATTERNS
+Line 4502 
 CONDITIONAL SUBPATTERNS
     Checking for pattern recursion
         If the condition is the string (R), and there is no subpattern with the
-        name  R, the condition is true if a recursive call to the whole pattern
+        name R, the condition is true if a recursive call to the whole  pattern
         or any subpattern has been made. If digits or a name preceded by amper-
         sand follow the letter R, for example:
           (?(R3)...) or (?(R&name)...)
-        the  condition is true if the most recent recursion is into the subpat-
+        the condition is true if the most recent recursion is into the  subpat-
-        tern whose number or name is given. This condition does not  check  the
+        tern  whose  number or name is given. This condition does not check the
         entire recursion stack.
-        At  "top  level", all these recursion test conditions are false. Recur-
+        At "top level", all these recursion test conditions are  false.  Recur-
         sive patterns are described below.
     Defining subpatterns for use by reference only
-        If the condition is the string (DEFINE), and  there  is  no  subpattern
+        If  the  condition  is  the string (DEFINE), and there is no subpattern
-        with  the  name  DEFINE,  the  condition is always false. In this case,
+        with the name DEFINE, the condition is  always  false.  In  this  case,
-        there may be only one alternative  in  the  subpattern.  It  is  always
+        there  may  be  only  one  alternative  in the subpattern. It is always
-        skipped  if  control  reaches  this  point  in the pattern; the idea of
+        skipped if control reaches this point  in  the  pattern;  the  idea  of
-        DEFINE is that it can be used to define "subroutines" that can be  ref-
+        DEFINE  is that it can be used to define "subroutines" that can be ref-
-        erenced  from elsewhere. (The use of "subroutines" is described below.)
+        erenced from elsewhere. (The use of "subroutines" is described  below.)
-        For example, a pattern to match an IPv4 address could be  written  like
+        For  example,  a pattern to match an IPv4 address could be written like
         this (ignore whitespace and line breaks):
           (?(DEFINE) (?<byte> 2[0-4]\d | 25[0-5] | 1\d\d | [1-9]?\d) )
           \b (?&byte) (\.(?&byte)){3} \b
-        The  first part of the pattern is a DEFINE group inside which a another
+        The first part of the pattern is a DEFINE group inside which a  another
-        group named "byte" is defined. This matches an individual component  of
+        group  named "byte" is defined. This matches an individual component of
-        an  IPv4  address  (a number less than 256). When matching takes place,
+        an IPv4 address (a number less than 256). When  matching  takes  place,
-        this part of the pattern is skipped because DEFINE acts  like  a  false
+        this  part  of  the pattern is skipped because DEFINE acts like a false
         condition.
         The rest of the pattern uses references to the named group to match the
-        four dot-separated components of an IPv4 address, insisting on  a  word
+        four  dot-separated  components of an IPv4 address, insisting on a word
         boundary at each end.
     Assertion conditions
-        If  the  condition  is  not  in any of the above formats, it must be an
+        If the condition is not in any of the above  formats,  it  must  be  an
-        assertion.  This may be a positive or negative lookahead or  lookbehind
+        assertion.   This may be a positive or negative lookahead or lookbehind
-        assertion.  Consider  this  pattern,  again  containing non-significant
+        assertion. Consider  this  pattern,  again  containing  non-significant
         white space, and with the two alternatives on the second line:
           (?(?=[^a-z]*[a-z])
           \d{2}-[a-z]{3}-\d{2}  |  \d{2}-\d{2}-\d{2} )
-        The condition  is  a  positive  lookahead  assertion  that  matches  an
+        The  condition  is  a  positive  lookahead  assertion  that  matches an
-        optional  sequence of non-letters followed by a letter. In other words,
+        optional sequence of non-letters followed by a letter. In other  words,
-        it tests for the presence of at least one letter in the subject.  If  a
+        it  tests  for the presence of at least one letter in the subject. If a
-        letter  is found, the subject is matched against the first alternative;
+        letter is found, the subject is matched against the first  alternative;
-        otherwise it is  matched  against  the  second.  This  pattern  matches
+        otherwise  it  is  matched  against  the  second.  This pattern matches
-        strings  in  one  of the two forms dd-aaa-dd or dd-dd-dd, where aaa are
+        strings in one of the two forms dd-aaa-dd or dd-dd-dd,  where  aaa  are
         letters and dd are digits.
  COMMENTS
-        The sequence (?# marks the start of a comment that continues up to  the
+        The  sequence (?# marks the start of a comment that continues up to the
-        next  closing  parenthesis.  Nested  parentheses are not permitted. The
+        next closing parenthesis. Nested parentheses  are  not  permitted.  The
-        characters that make up a comment play no part in the pattern  matching
+        characters  that make up a comment play no part in the pattern matching
         at all.
-        If  the PCRE_EXTENDED option is set, an unescaped # character outside a
+        If the PCRE_EXTENDED option is set, an unescaped # character outside  a
-        character class introduces a  comment  that  continues  to  immediately
+        character  class  introduces  a  comment  that continues to immediately
         after the next newline in the pattern.
  RECURSIVE PATTERNS
-        Consider  the problem of matching a string in parentheses, allowing for
+        Consider the problem of matching a string in parentheses, allowing  for
-        unlimited nested parentheses. Without the use of  recursion,  the  best
+        unlimited  nested  parentheses.  Without the use of recursion, the best
-        that  can  be  done  is  to use a pattern that matches up to some fixed
+        that can be done is to use a pattern that  matches  up  to  some  fixed
-        depth of nesting. It is not possible to  handle  an  arbitrary  nesting
+        depth  of  nesting.  It  is not possible to handle an arbitrary nesting