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-revision 73 by nigel,
Sat Feb 24 21:40:30 2007 UTC
+revision 75 by nigel,
Sat Feb 24 21:40:37 2007 UTC
 Line 1
+ -----------------------------------------------------------------------------
  This file contains a concatenation of the PCRE man pages, converted to plain
  text format for ease of searching with a text editor, or for use on systems
  that do not have a man page processor. The small individual files that give
-Line 12 
 PCRE(3)
+Line 13 
 PCRE(3)
  NAME
         PCRE - Perl-compatible regular expressions
- DESCRIPTION
+ INTRODUCTION
         The  PCRE  library is a set of functions that implement regular expres-
         sion pattern matching using the same syntax and semantics as Perl, with
         just  a  few  differences.  The current implementation of PCRE (release
 .x) corresponds approximately with Perl  5.8,  including  support  for
-        UTF-8  encoded  strings.   However,  this  support has to be explicitly
+        UTF-8 encoded strings and Unicode general category properties. However,
-        enabled; it is not the default.
+        this support has to be explicitly enabled; it is not the default.
-        PCRE is written in C and released as a C library. However, a number  of
+        PCRE is written in C and released as a C library. A  number  of  people
-        people  have  written  wrappers  and interfaces of various kinds. A C++
+        have  written  wrappers and interfaces of various kinds. A C++ class is
-        class is included in these contributions, which can  be  found  in  the
+        included in these contributions, which can  be  found  in  the  Contrib
-        Contrib directory at the primary FTP site, which is:
+        directory at the primary FTP site, which is:
         ftp://ftp.csx.cam.ac.uk/pub/software/programming/pcre
-Line 34 
 DESCRIPTION
+Line 35 
 DESCRIPTION
         Some  features  of  PCRE can be included, excluded, or changed when the
         library is built. The pcre_config() function makes it  possible  for  a
-        client  to  discover  which features are available. Documentation about
+        client  to  discover  which  features are available. The features them-
-        building PCRE for various operating systems can be found in the  README
+        selves are described in the pcrebuild page. Documentation about  build-
-        file in the source distribution.
+        ing  PCRE for various operating systems can be found in the README file
+        in the source distribution.
  USER DOCUMENTATION
-        The user documentation for PCRE has been split up into a number of dif-
+        The user documentation for PCRE comprises a number  of  different  sec-
-        ferent sections. In the "man" format, each of these is a separate  "man
+        tions.  In the "man" format, each of these is a separate "man page". In
-        page".  In  the  HTML  format, each is a separate page, linked from the
+        the HTML format, each is a separate page, linked from the  index  page.
-        index page. In the plain text format, all  the  sections  are  concate-
+        In  the  plain text format, all the sections are concatenated, for ease
-        nated, for ease of searching. The sections are as follows:
+        of searching. The sections are as follows:
           pcre              this document
           pcreapi           details of PCRE's native API
-Line 53 
 USER DOCUMENTATION
+Line 55 
 USER DOCUMENTATION
           pcrecallout       details of the callout feature
           pcrecompat        discussion of Perl compatibility
           pcregrep          description of the pcregrep command
+          pcrepartial       details of the partial matching facility
           pcrepattern       syntax and semantics of supported
                               regular expressions
           pcreperform       discussion of performance issues
           pcreposix         the POSIX-compatible API
+          pcreprecompile    details of saving and re-using precompiled patterns
           pcresample        discussion of the sample program
-          pcretest          the pcretest testing command
+          pcretest          description of the pcretest testing command
         In  addition,  in the "man" and HTML formats, there is a short page for
         each library function, listing its arguments and results.
-Line 74 
 LIMITATIONS
+Line 78 
 LIMITATIONS
         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
         the  source  distribution and the pcrebuild documentation for details).
-        If these cases the limit is substantially larger.  However,  the  speed
+        In these cases the limit is substantially larger.  However,  the  speed
         of execution will be slower.
         All values in repeating quantifiers must be less than 65536.  The maxi-
-Line 92 
 LIMITATIONS
+Line 96 
 LIMITATIONS
         processed by certain patterns.
- UTF-8 SUPPORT
+ UTF-8 AND UNICODE PROPERTY SUPPORT
-        Starting  at  release  3.3,  PCRE  has  had  some support for character
+        From  release  3.3,  PCRE  has  had  some support for character strings
-        strings encoded in the UTF-8 format. For  release  4.0  this  has  been
+        encoded in the UTF-8 format. For release 4.0 this was greatly  extended
-        greatly extended to cover most common requirements.
+        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
-        support in the code, and, in addition,  you  must  call  pcre_compile()
+        In order process UTF-8 strings, you must build PCRE  to  include  UTF-8
-        with  the PCRE_UTF8 option flag. When you do this, both the pattern and
+        support  in  the  code,  and, in addition, you must call pcre_compile()
-        any subject strings that are matched against it are  treated  as  UTF-8
+        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
         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 in several places, so should
+        is limited to testing the PCRE_UTF8 flag in several places,  so  should
         not be very large.
+        If PCRE is built with Unicode character property support (which implies
+        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
+        for  a decimal number. A full list is given in the pcrepattern documen-
+        tation. The PCRE library is increased in size by about 90K when Unicode
+        property support is included.
         The following comments apply when PCRE is running in UTF-8 mode:
-. When you set the PCRE_UTF8 flag, the strings passed as patterns  and
+.  When you set the PCRE_UTF8 flag, the strings passed as patterns and
-        subjects  are  checked for validity on entry to the relevant functions.
+        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
+        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,
+        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)
+        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
+        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
+        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
+        PCRE_NO_UTF8_CHECK is set, the results are undefined. Your program  may
         crash.
 . In a pattern, the escape sequence \x{...}, where the contents of the
-        braces  is  a  string  of hexadecimal digits, is interpreted as a UTF-8
+        braces is a string of hexadecimal digits, is  interpreted  as  a  UTF-8
-        character whose code number is the given hexadecimal number, for  exam-
+        character  whose code number is the given hexadecimal number, for exam-
-        ple:  \x{1234}.  If a non-hexadecimal digit appears between the braces,
+        ple: \x{1234}. If a non-hexadecimal digit appears between  the  braces,
         the item is not recognized.  This escape sequence can be used either as
         a literal, or within a character class.
-.  The  original hexadecimal escape sequence, \xhh, matches a two-byte
+. The original hexadecimal escape sequence, \xhh, matches  a  two-byte
         UTF-8 character if the value is greater than 127.
-. 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
+. The dot metacharacter matches one UTF-8 character instead of a  sin-
-        single byte.
+        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.
-.  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.
+        before, all with values less than 256. This remains true even when PCRE
+        includes Unicode property support, because to do otherwise  would  slow
-. Case-insensitive matching applies only to  characters  whose  values
+        down  PCRE in many common cases. If you really want to test for a wider
-        are  less  than  256.  PCRE  does  not support the notion of "case" for
+        sense of, say, "digit", you must use Unicode  property  tests  such  as
-        higher-valued characters.
+        \p{Nd}.
-. PCRE does not support the use of Unicode tables  and  properties  or
+.  Similarly,  characters that match the POSIX named character classes
-        the Perl escapes \p, \P, and \X.
+        are all low-valued characters.
+. 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.
  AUTHOR
-Line 162 
 AUTHOR
+Line 182 
 AUTHOR
         Cambridge CB2 3QG, England.
         Phone: +44 1223 334714
- Last updated: 20 August 2003
+ Last updated: 09 September 2004
- Copyright (c) 1997-2003 University of Cambridge.
+ Copyright (c) 1997-2004 University of Cambridge.
  -----------------------------------------------------------------------------
  PCRE(3)                                                                PCRE(3)
-Line 177 
 PCRE BUILD-TIME OPTIONS
+Line 197 
 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-
-        lected,  by  providing  options  to  the  configure script which is run
+        lected, by providing options to the configure script that is run before
-        before the make command. The complete list  of  options  for  configure
+        the make command. The complete list of  options  for  configure  (which
-        (which  includes the standard ones such as the selection of the instal-
+        includes  the  standard  ones such as the selection of the installation
-        lation directory) can be obtained by running
+        directory) can be obtained by running
           ./configure --help
-Line 204 
 UTF-8 SUPPORT
+Line 224 
 UTF-8 SUPPORT
         function.
+ UNICODE CHARACTER PROPERTY SUPPORT
+        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-
+        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
+        refer to Unicode character properties, you must add
+          --enable-unicode-properties
+        to the configure command. This implies UTF-8 support, even if you  have
+        not explicitly requested it.
+        Including  Unicode  property  support  adds around 90K of tables to the
+        PCRE library, approximately doubling its size. Only the  general  cate-
+        gory  properties  such as Lu and Nd are supported. Details are given in
+        the pcrepattern documentation.
  CODE VALUE OF NEWLINE
         By default, PCRE treats character 10 (linefeed) as the newline  charac-
-Line 231 
 BUILDING SHARED AND STATIC LIBRARIES
+Line 270 
 BUILDING SHARED AND STATIC LIBRARIES
  POSIX MALLOC USAGE
-        When PCRE is called through the  POSIX  interface  (see  the  pcreposix
+        When PCRE is called through the POSIX interface (see the pcreposix doc-
-        documentation),  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
         number of expected substrings is small, the wrapper function uses space
         on the stack, because this is faster than using malloc() for each call.
-Line 247 
 POSIX MALLOC USAGE
+Line 286 
 POSIX MALLOC USAGE
  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 (possibly recursively) when performing a  matching  operation.  By
+        edly (possibly recursively) when matching a pattern. By controlling the
-        limiting  the  number of times this function may be called, a limit can
+        maximum  number  of  times  this function may be called during a single
-        be placed on the resources used by a single call  to  pcre_exec().  The
+        matching operation, a limit can be placed on the resources  used  by  a
-        limit  can be changed at run time, as described in the pcreapi documen-
+        single  call  to  pcre_exec(). The limit can be changed at run time, as
-        tation. The default is 10 million, but this can be changed by adding  a
+        described in the pcreapi documentation. The default is 10 million,  but
-        setting such as
+        this can be changed by adding a setting such as
           --with-match-limit=500000
-Line 264 
 HANDLING VERY LARGE PATTERNS
+Line 303 
 HANDLING VERY LARGE PATTERNS
         Within  a  compiled  pattern,  offset values are used to point from one
         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
 K.  This  is sufficient to handle all but the most gigantic patterns.
         Nevertheless, some people do want to process enormous patterns,  so  it
-Line 297 
 AVOIDING EXCESSIVE STACK USAGE
+Line 336 
 AVOIDING EXCESSIVE STACK USAGE
           --disable-stack-for-recursion
         to the configure command. With this configuration, PCRE  will  use  the
-        pcre_stack_malloc   and   pcre_stack_free   variables  to  call  memory
+        pcre_stack_malloc  and pcre_stack_free variables to call memory manage-
-        management functions. Separate functions are provided because the usage
+        ment functions. Separate functions are provided because  the  usage  is
-        is very predictable: the block sizes requested are always the same, and
+        very  predictable:  the  block sizes requested are always the same, and
         the blocks are always freed in reverse order. A calling  program  might
         be  able  to implement optimized functions that perform better than the
         standard malloc() and  free()  functions.  PCRE  runs  noticeably  more
-Line 309 
 AVOIDING EXCESSIVE STACK USAGE
+Line 348 
 AVOIDING EXCESSIVE STACK USAGE
  USING EBCDIC CODE
         PCRE  assumes  by  default that it will run in an environment where the
-        character code is ASCII (or UTF-8, which is a superset of ASCII).  PCRE
+        character code is ASCII (or Unicode, which is  a  superset  of  ASCII).
-        can, however, be compiled to run in an EBCDIC environment by adding
+        PCRE  can,  however,  be  compiled  to  run in an EBCDIC environment by
+        adding
           --enable-ebcdic
         to the configure command.
- Last updated: 09 December 2003
+ Last updated: 09 September 2004
- Copyright (c) 1997-2003 University of Cambridge.
+ Copyright (c) 1997-2004 University of Cambridge.
  -----------------------------------------------------------------------------
  PCRE(3)                                                                PCRE(3)
-Line 327 
 PCRE(3)
+Line 367 
 PCRE(3)
  NAME
         PCRE - Perl-compatible regular expressions
- SYNOPSIS OF PCRE API
+ PCRE NATIVE API
         #include <pcre.h>
-Line 392 
 SYNOPSIS OF PCRE API
+Line 432 
 SYNOPSIS OF PCRE API
         int (*pcre_callout)(pcre_callout_block *);
- PCRE API
+ PCRE API OVERVIEW
         PCRE has its own native API, which is described in this document. There
         is also a set of wrapper functions that correspond to the POSIX regular
         expression API.  These are described in the pcreposix documentation.
         The  native  API  function  prototypes  are  defined in the header file
-        pcre.h, and on Unix systems the library itself is called libpcre.a,  so
+        pcre.h, and on Unix systems the library itself is  called  libpcre.  It
-        can be accessed by adding -lpcre to the command for linking an applica-
+        can normally be accessed by adding -lpcre to the command for linking an
-        tion which calls it. The header file defines the macros PCRE_MAJOR  and
+        application  that  uses  PCRE.  The  header  file  defines  the  macros
-        PCRE_MINOR  to  contain  the  major  and  minor release numbers for the
+        PCRE_MAJOR  and  PCRE_MINOR to contain the major and minor release num-
-        library. Applications can use these to include  support  for  different
+        bers for the library.  Applications can use these  to  include  support
-        releases.
+        for different releases of PCRE.
         The  functions  pcre_compile(),  pcre_study(), and pcre_exec() are used
         for compiling and matching regular expressions. A sample  program  that
-        demonstrates  the simplest way of using them is given in the file pcre-
+        demonstrates  the  simplest  way  of using them is provided in the file
-        demo.c. The pcresample documentation describes how to run it.
+        called pcredemo.c in the source distribution. The pcresample documenta-
+        tion describes how to run it.
-        There are convenience functions for extracting captured substrings from
-        a matched subject string. They are:
+        In  addition  to  the  main compiling and matching functions, there are
+        convenience functions for extracting captured substrings from a matched
+        subject string.  They are:
           pcre_copy_substring()
           pcre_copy_named_substring()
           pcre_get_substring()
           pcre_get_named_substring()
           pcre_get_substring_list()
+          pcre_get_stringnumber()
         pcre_free_substring() and pcre_free_substring_list() are also provided,
         to free the memory used for extracted strings.
-        The function pcre_maketables() is used (optionally) to build a  set  of
+        The function pcre_maketables() is used to  build  a  set  of  character
-        character tables in the current locale for passing to pcre_compile().
+        tables   in  the  current  locale  for  passing  to  pcre_compile()  or
+        pcre_exec().  This is an optional facility that is  provided  for  spe-
-        The  function  pcre_fullinfo()  is used to find out information about a
+        cialist use. Most commonly, no special tables are passed, in which case
-        compiled pattern; pcre_info() is an obsolete version which returns only
+        internal tables that are generated when PCRE is built are used.
-        some  of  the available information, but is retained for backwards com-
-        patibility.  The function pcre_version() returns a pointer to a  string
+        The function pcre_fullinfo() is used to find out  information  about  a
+        compiled  pattern; pcre_info() is an obsolete version that returns only
+        some of the available information, but is retained for  backwards  com-
+        patibility.   The function pcre_version() returns a pointer to a string
         containing the version of PCRE and its date of release.
-        The  global  variables  pcre_malloc and pcre_free initially contain the
+        The global variables pcre_malloc and pcre_free  initially  contain  the
-        entry points of the standard  malloc()  and  free()  functions  respec-
+        entry  points  of  the  standard malloc() and free() functions, respec-
         tively. PCRE calls the memory management functions via these variables,
-        so a calling program can replace them if it  wishes  to  intercept  the
+        so  a  calling  program  can replace them if it wishes to intercept the
         calls. This should be done before calling any PCRE functions.
-        The  global  variables  pcre_stack_malloc  and pcre_stack_free are also
+        The global variables pcre_stack_malloc  and  pcre_stack_free  are  also
-        indirections to memory management functions.  These  special  functions
+        indirections  to  memory  management functions. These special functions
-        are  used  only  when  PCRE is compiled to use the heap for remembering
+        are used only when PCRE is compiled to use  the  heap  for  remembering
-        data, instead of recursive function calls. This is a  non-standard  way
+        data,  instead  of recursive function calls. This is a non-standard way
-        of  building  PCRE,  for  use in environments that have limited stacks.
+        of building PCRE, for use in environments  that  have  limited  stacks.
-        Because of the greater use of memory management, it runs  more  slowly.
+        Because  of  the greater use of memory management, it runs more slowly.
-        Separate  functions  are provided so that special-purpose external code
+        Separate functions are provided so that special-purpose  external  code
         can be used for this case. When used, these functions are always called
-        in  a  stack-like  manner  (last obtained, first freed), and always for
+        in a stack-like manner (last obtained, first  freed),  and  always  for
         memory blocks of the same size.
         The global variable pcre_callout initially contains NULL. It can be set
-        by  the  caller  to  a "callout" function, which PCRE will then call at
+        by the caller to a "callout" function, which PCRE  will  then  call  at
-        specified points during a matching operation. Details are given in  the
+        specified  points during a matching operation. Details are given in the
         pcrecallout documentation.
  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.
+ 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
+        than the one on which  it  was  compiled.  Details  are  given  in  the
+        pcreprecompile documentation.
  CHECKING BUILD-TIME OPTIONS
         int pcre_config(int what, void *where);
-Line 486 
 CHECKING BUILD-TIME OPTIONS
+Line 540 
 CHECKING BUILD-TIME OPTIONS
         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
+        character properties is available; otherwise it is set to zero.
           PCRE_CONFIG_NEWLINE
-        The output is an integer that is set to the value of the code  that  is
+        The  output  is an integer that is set to the value of the code that is
-        used  for the newline character. It is either linefeed (10) or carriage
+        used for the newline character. It is either linefeed (10) or  carriage
-        return (13), and should normally be the  standard  character  for  your
+        return  (13),  and  should  normally be the standard character for your
         operating system.
           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_STACKRECURSE
-        The output is an integer that is set to one if  internal  recursion  is
+        The  output  is  an integer that is set to one if internal recursion is
-        implemented  by recursive function calls that use the stack to remember
+        implemented by recursive function calls that use 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
+        zero if PCRE was compiled to use blocks of data on the heap instead  of
-        recursive  function  calls.  In  this   case,   pcre_stack_malloc   and
+        recursive   function   calls.   In  this  case,  pcre_stack_malloc  and
-        pcre_stack_free  are  called  to manage memory blocks on the heap, thus
+        pcre_stack_free are called to manage memory blocks on  the  heap,  thus
         avoiding the use of the stack.
-Line 531 
 COMPILING A PATTERN
+Line 590 
 COMPILING A PATTERN
              const char **errptr, int *erroffset,
              const unsigned char *tableptr);
+        The  function  pcre_compile()  is  called  to compile a pattern into an
-        The function pcre_compile() is called to  compile  a  pattern  into  an
+        internal form. The pattern is a C string terminated by a  binary  zero,
-        internal  form.  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
-        and is passed in the argument pattern. A pointer to a single  block  of
+        memory that is obtained via pcre_malloc is returned. This contains  the
-        memory  that is obtained via pcre_malloc is returned. This contains the
+        compiled  code  and  related  data.  The  pcre  type is defined for 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
-        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 when
-        not externally defined. It is up to the caller to free the memory  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 contains a copy of the tableptr argument,
+        fully relocatable, because it may contain a copy of the tableptr  argu-
-        which is an address (see below).
+        ment, which is an address (see below).
         The options argument contains independent bits that affect the compila-
-        tion.  It  should  be  zero  if  no  options  are required. Some of the
+        tion. It should be zero if  no  options  are  required.  The  available
-        options, in particular, those that are compatible with Perl,  can  also
+        options  are  described  below. Some of them, in particular, those that
-        be  set and unset from within the pattern (see the detailed description
+        are compatible with Perl, can also be set and  unset  from  within  the
-        of regular expressions in the  pcrepattern  documentation).  For  these
+        pattern  (see  the  detailed  description in the pcrepattern documenta-
-        options,  the  contents of the options argument specifies their initial
+        tion). For these options, the contents of the options  argument  speci-
-        settings at the start of compilation and execution.  The  PCRE_ANCHORED
+        fies  their initial settings at the start of compilation and execution.
-        option can be set at the time of matching as well as at compile time.
+        The PCRE_ANCHORED option 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
-Line 564 
 COMPILING A PATTERN
+Line 623 
 COMPILING A PATTERN
         given.
         If  the  final  argument, tableptr, is NULL, PCRE uses a default set of
-        character tables which are built when it is compiled, using the default
+        character tables that are  built  when  PCRE  is  compiled,  using  the
-        C  locale.  Otherwise,  tableptr  must  be  the  result  of  a  call to
+        default  C  locale.  Otherwise, tableptr must be an address that is the
-        pcre_maketables(). See the section on locale support below.
+        result of a call to pcre_maketables(). This value is  stored  with  the
+        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 581 
 COMPILING A PATTERN
+Line 643 
 COMPILING A PATTERN
             &erroffset,       /* for error offset */
             NULL);            /* use default character tables */
-        The following option bits are defined:
+        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
-        which 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
         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
+        callout facility, see the pcrecallout documentation.
           PCRE_CASELESS
         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
-        changed within a pattern by a (?i) option setting.
+        changed  within  a  pattern  by  a (?i) option setting. When running in
+        UTF-8 mode, case support for high-valued characters is  available  only
+        when PCRE is built with Unicode character property support.
           PCRE_DOLLAR_ENDONLY
-Line 645 
 COMPILING A PATTERN
+Line 716 
 COMPILING A PATTERN
           PCRE_MULTILINE
         By default, PCRE treats the subject string as consisting  of  a  single
-        "line"  of  characters (even if it actually contains several newlines).
+        line  of characters (even if it actually contains newlines). The "start
-        The "start of line" metacharacter (^) matches only at the start of  the
+        of line" metacharacter (^) matches only at the  start  of  the  string,
-        string,  while  the "end of line" metacharacter ($) matches only at the
+        while  the  "end  of line" metacharacter ($) matches only at the end of
-        end of the string, or before a terminating  newline  (unless  PCRE_DOL-
+        the string, or before a terminating newline (unless PCRE_DOLLAR_ENDONLY
-        LAR_ENDONLY is set). This is the same as Perl.
+        is set). This is the same as Perl.
         When  PCRE_MULTILINE  it  is set, the "start of line" and "end of line"
         constructs match immediately following or immediately before  any  new-
-Line 678 
 COMPILING A PATTERN
+Line 749 
 COMPILING A PATTERN
         This option causes PCRE to regard both the pattern and the  subject  as
         strings  of  UTF-8 characters instead of single-byte character strings.
-        However, it is available only if PCRE has been built to  include  UTF-8
+        However, it is available only when PCRE is built to include UTF-8  sup-
-        support.  If  not, the use of this option provokes an error. Details of
+        port.  If not, the use of this option provokes an error. Details of how
-        how this option changes the behaviour of PCRE are given in the  section
+        this option changes the behaviour of PCRE are given in the  section  on
-        on UTF-8 support in the main pcre page.
+        UTF-8 support in the main pcre page.
           PCRE_NO_UTF8_CHECK
-Line 691 
 COMPILING A PATTERN
+Line 762 
 COMPILING A PATTERN
         is valid, and you want to skip this check for performance reasons,  you
         can  set  the  PCRE_NO_UTF8_CHECK option. When it is set, the effect of
         passing an invalid UTF-8 string as a pattern is undefined. It may cause
-        your  program  to  crash.  Note that there is a similar option for sup-
+        your  program  to  crash.   Note that this option can also be passed to
-        pressing the checking of subject strings passed to pcre_exec().
+        pcre_exec(),  to  suppress  the  UTF-8  validity  checking  of  subject
+        strings.
  STUDYING A PATTERN
-Line 701 
 STUDYING A PATTERN
+Line 772 
 STUDYING A PATTERN
         pcre_extra *pcre_study(const pcre *code, int options,
              const char **errptr);
-        When a pattern is going to be used several times, it is worth  spending
+        If  a  compiled  pattern is going to be used several times, it is worth
-        more  time  analyzing it in order to speed up the time taken for match-
+        spending more time analyzing it in order to speed up the time taken for
-        ing. The function pcre_study() takes a pointer to a compiled pattern as
+        matching.  The function pcre_study() takes a pointer to a compiled pat-
-        its first argument. If studing the pattern produces additional informa-
+        tern as its first argument. If studying the pattern produces additional
-        tion that will help speed up matching, pcre_study() returns  a  pointer
+        information  that  will  help speed up matching, pcre_study() returns a
-        to  a  pcre_extra  block,  in  which the study_data field points to the
+        pointer to a pcre_extra block, in which the study_data field points  to
-        results of the study.
+        the results of the study.
-        The returned value from  a  pcre_study()  can  be  passed  directly  to
+        The  returned  value  from  pcre_study()  can  be  passed  directly  to
-        pcre_exec().  However,  the 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.  If  studying  the pattern does not produce any addi-
+        described below in the section on matching a pattern.
-        tional information, pcre_study() returns NULL. In that circumstance, if
-        the  calling  program  wants  to  pass  some  of  the  other  fields to
+        If studying the pattern does not produce  any  additional  information,
-        pcre_exec(), it must set up its own pcre_extra block.
+        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
-        The second argument contains option bits. At present,  no  options  are
+        its own pcre_extra block.
-        defined for pcre_study(), and this argument should always be zero.
+        The  second  argument of pcre_study() contains option bits. At present,
-        The  third argument for pcre_study() is a pointer for an error message.
+        no options are defined, and this argument should always be zero.
-        If studying succeeds (even if no data is  returned),  the  variable  it
-        points  to  is set to NULL. Otherwise it points to a textual error mes-
+        The third argument for pcre_study() is a pointer for an error  message.
-        sage. You should therefore test the error pointer for NULL after  call-
+        If  studying  succeeds  (even  if no data is returned), the variable it
+        points to is set to NULL. Otherwise it points to a textual  error  mes-
+        sage.  You should therefore test the error pointer for NULL after call-
         ing pcre_study(), to be sure that it has run successfully.
         This is a typical call to pcre_study():
-Line 735 
 STUDYING A PATTERN
+Line 808 
 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 characters is created.
+        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.  When
+        letters,  digits, or whatever, by reference to a set of tables, indexed
-        running  in UTF-8 mode, this applies only to characters with codes less
+        by character value. (When running in UTF-8 mode, this applies  only  to
-        than 256. The library contains a default set of tables that is  created
+        characters  with  codes  less than 128. Higher-valued codes never match
-        in  the  default  C locale when PCRE is compiled. This is used when the
+        escapes such as \w or \d, but can be tested with \p if  PCRE  is  built
-        final argument of pcre_compile() is NULL, and is  sufficient  for  many
+        with Unicode character property support.)
-        applications.
+        An  internal set of tables is created in the default C locale when PCRE
-        An alternative set of tables can, however, be supplied. Such tables are
+        is built. This is used when the final  argument  of  pcre_compile()  is
-        built by calling the pcre_maketables() function,  which  has  no  argu-
+        NULL,  and  is  sufficient for many applications. An alternative set of
-        ments,  in  the  relevant  locale.  The  result  can  then be passed to
+        tables can, however, be supplied. These may be created in  a  different
-        pcre_compile() as often as necessary. For example,  to  build  and  use
+        locale  from the default. As more and more applications change to using
-        tables that are appropriate for the French locale (where accented char-
+        Unicode, the need for this locale support is expected to die away.
-        acters with codes greater than 128 are treated as letters), the follow-
-        ing code could be used:
+        External tables are built by calling  the  pcre_maketables()  function,
+        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
+        example,  to  build  and use tables that are appropriate for the French
+        locale (where accented characters with  values  greater  than  128  are
+        treated as letters), the following code could be used:
-          setlocale(LC_CTYPE, "fr");
+          setlocale(LC_CTYPE, "fr_FR");
           tables = pcre_maketables();
           re = pcre_compile(..., tables);
-        The  tables  are  built in memory that is obtained via pcre_malloc. The
+        When  pcre_maketables()  runs,  the  tables are built in memory that is
-        pointer that is passed to pcre_compile is saved with the compiled  pat-
+        obtained via pcre_malloc. It is the caller's responsibility  to  ensure
-        tern, and the same tables are used via this pointer by pcre_study() and
+        that  the memory containing the tables remains available for as long as
-        pcre_exec(). Thus, for any single pattern,  compilation,  studying  and
+        it is needed.
-        matching  all  happen in the same locale, but different patterns can be
-        compiled in different locales. It is  the  caller's  responsibility  to
+        The pointer that is passed to pcre_compile() is saved with the compiled
-        ensure  that  the memory containing the tables remains available for as
+        pattern,  and the same tables are used via this pointer by pcre_study()
-        long as it is needed.
+        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
+        the  internal  tables)  to  pcre_exec(). Although not intended for this
+        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.
  INFORMATION ABOUT A PATTERN
-Line 792 
 INFORMATION ABOUT A PATTERN
+Line 878 
 INFORMATION ABOUT A PATTERN
           PCRE_ERROR_BADMAGIC   the "magic number" was not found
           PCRE_ERROR_BADOPTION  the value of what was invalid
-        Here  is a typical call of pcre_fullinfo(), to obtain the length of the
+        The  "magic  number" is placed at the start of each compiled pattern as
-        compiled pattern:
+        an simple check against passing an arbitrary memory pointer. Here is  a
+        typical  call  of pcre_fullinfo(), to obtain the length of the compiled
+        pattern:
           int rc;
           unsigned long int length;
-Line 817 
 INFORMATION ABOUT A PATTERN
+Line 905 
 INFORMATION ABOUT A PATTERN
         Return  the  number of capturing subpatterns in the pattern. The fourth
         argument should point to an int variable.
+          PCRE_INFO_DEFAULTTABLES
+        Return a pointer to the internal default character tables within  PCRE.
+        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
+        passing a NULL table pointer.
           PCRE_INFO_FIRSTBYTE
         Return information about the first byte of any matched  string,  for  a
-Line 824 
 INFORMATION ABOUT A PATTERN
+Line 920 
 INFORMATION ABOUT A PATTERN
         PCRE_INFO_FIRSTCHAR; the old name is  still  recognized  for  backwards
         compatibility.)
-        If  there  is  a  fixed  first  byte,  e.g.  from  a  pattern  such  as
+        If  there  is  a  fixed first byte, for example, from a pattern such as
         (cat|cow|coyote), it is returned in the integer pointed  to  by  where.
         Otherwise, if either
-Line 862 
 INFORMATION ABOUT A PATTERN
+Line 958 
 INFORMATION ABOUT A PATTERN
         PCRE  supports the use of named as well as numbered capturing parenthe-
         ses. The names are just an additional way of identifying the  parenthe-
-        ses,  which still acquire a number. A caller that wants to extract data
+        ses,  which  still  acquire  numbers.  A  convenience  function  called
-        from a named subpattern must convert the name to a number in  order  to
+        pcre_get_named_substring() is provided  for  extracting  an  individual
-        access  the  correct  pointers  in  the  output  vector (described with
+        captured  substring  by  name.  It is also possible to extract the data
-        pcre_exec() below). In order to do this, it must first use these  three
+        directly, by first converting the name to a number in order  to  access
-        values to obtain the name-to-number mapping table for the pattern.
+        the  correct  pointers in the output vector (described with pcre_exec()
+        below). To do the conversion, you need to use the  name-to-number  map,
+        which is described by these three values.
         The map consists of a number of fixed-size entries. PCRE_INFO_NAMECOUNT
         gives the number of entries, and PCRE_INFO_NAMEENTRYSIZE gives the size
-Line 884 
 INFORMATION ABOUT A PATTERN
+Line 982 
 INFORMATION ABOUT A PATTERN
         There are four named subpatterns, so the table has  four  entries,  and
         each  entry  in the table is eight bytes long. The table is as follows,
-        with non-printing bytes shows in hex, and undefined bytes shown as ??:
+        with non-printing bytes shows in hexadecimal, and undefined bytes shown
+        as ??:
 01 d  a  t  e  00 ??
 05 d  a  y  00 ?? ??
 04 m  o  n  t  h  00
 02 y  e  a  r  00 ??
-        When writing code to extract data from named subpatterns, remember that
+        When  writing  code  to  extract  data from named subpatterns using the
-        the length of each entry may be different for each compiled pattern.
+        name-to-number map, remember that the length of each entry is likely to
+        be different for each compiled pattern.
           PCRE_INFO_OPTIONS
-Line 922 
 INFORMATION ABOUT A PATTERN
+Line 1022 
 INFORMATION ABOUT A PATTERN
           PCRE_INFO_STUDYSIZE
-        Returns  the  size of the data block pointed to by the study_data field
+        Return the size of the data block pointed to by the study_data field in
-        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
         variable.
-Line 958 
 MATCHING A PATTERN
+Line 1058 
 MATCHING A PATTERN
              int options, int *ovector, int ovecsize);
         The  function pcre_exec() is called to match a subject string against a
-        pre-compiled pattern, which is passed in the code argument. If the pat-
+        compiled pattern, which is passed in the code argument. If the  pattern
-        tern  has been studied, the result of the study should be passed in the
+        has been studied, the result of the study should be passed in the extra
-        extra argument.
+        argument.
+        In most applications, the pattern will have been compiled (and  option-
+        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
+        discussion about this, see the pcreprecompile documentation.
         Here is an example of a simple call to pcre_exec():
-Line 973 
 MATCHING A PATTERN
+Line 1079 
 MATCHING A PATTERN
 ,             /* the length of the subject string */
 ,              /* start at offset 0 in the subject */
 ,              /* default options */
-            ovector,        /* vector for substring information */
+            ovector,        /* vector of integers for substring information */
-);            /* number of elements in the vector */
+);            /* number of elements in the vector  (NOT  size  in
+        bytes) */
-        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
+    Extra data for pcre_exec()
-        return NULL), but you can also create one for yourself, and pass  addi-
-        tional information in it. The fields in the block are as follows:
+        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
+        return  NULL), but you can also create one for yourself, and pass addi-
+        tional information in it. The fields in a pcre_extra block are as  fol-
+        lows:
           unsigned long int flags;
           void *study_data;
           unsigned long int match_limit;
           void *callout_data;
+          const unsigned char *tables;
         The  flags  field  is a bitmap that specifies which of the other fields
         are set. The flag bits are:
-Line 992 
 MATCHING A PATTERN
+Line 1103 
 MATCHING A PATTERN
           PCRE_EXTRA_STUDY_DATA
           PCRE_EXTRA_MATCH_LIMIT
           PCRE_EXTRA_CALLOUT_DATA
+          PCRE_EXTRA_TABLES
         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 appropriate flag bit. You should not set this yourself, but you can
+        the appropriate flag bit. You should not set this yourself, but you may
-        add to the block by setting the other fields.
+        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
+        repeats.
-        repeatedly (sometimes recursively). The limit is imposed on the  number
-        of  times  this function is called during a match, which has the effect
+        Internally, PCRE uses a function called match() which it calls  repeat-
-        of limiting the amount of recursion  and  backtracking  that  can  take
+        edly  (sometimes  recursively).  The  limit is imposed on the number of
-        place.  For  patterns that are not anchored, the count starts from zero
+        times this function is called during a match, which has the  effect  of
-        for each position in the subject string.
+        limiting  the amount of recursion and backtracking that can take place.
+        For patterns that are not anchored, the count starts from zero for each
-        The default limit for the library can be set when PCRE  is  built;  the
+        position in the subject string.
-        default  default  is 10 million, which handles all but the most extreme
-        cases. You can reduce  the  default  by  suppling  pcre_exec()  with  a
+        The  default  limit  for the library can be set when PCRE is built; the
-        pcre_extra  block  in  which match_limit is set to a smaller value, and
+        default default is 10 million, which handles all but the  most  extreme
-        PCRE_EXTRA_MATCH_LIMIT is set in the  flags  field.  If  the  limit  is
+        cases.  You  can  reduce  the  default  by  suppling pcre_exec() with a
+        pcre_extra block in which match_limit is set to a  smaller  value,  and
+        PCRE_EXTRA_MATCH_LIMIT  is  set  in  the  flags  field. If the limit is
         exceeded, pcre_exec() returns PCRE_ERROR_MATCHLIMIT.
-        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 PCRE_ANCHORED option can be passed in the options  argument,  whose
+        The  tables  field  is  used  to  pass  a  character  tables pointer to
-        unused  bits  must  be zero. This limits pcre_exec() to matching at the
+        pcre_exec(); this overrides the value that is stored with the  compiled
-        first matching position.  However,  if  a  pattern  was  compiled  with
+        pattern.  A  non-NULL value is stored with the compiled pattern only if
-        PCRE_ANCHORED,  or turned out to be anchored by virtue of its contents,
+        custom tables were supplied to pcre_compile() via  its  tableptr  argu-
-        it cannot be made unachored at matching time.
+        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-
-        When PCRE_UTF8 was set at compile time, the validity of the subject  as
+        using  patterns  that  have been saved after compiling with an external
-        a  UTF-8  string is automatically checked, and the value of startoffset
+        set of tables, because the external tables  might  be  at  a  different
-        is also checked to ensure that it points to the start of a UTF-8  char-
+        address  when  pcre_exec() is called. See the pcreprecompile documenta-
-        acter.  If  an  invalid  UTF-8  sequence of bytes is found, pcre_exec()
+        tion for a discussion of saving compiled patterns for later use.
-        returns  the  error  PCRE_ERROR_BADUTF8.  If  startoffset  contains  an
-        invalid value, PCRE_ERROR_BADUTF8_OFFSET is returned.
+    Option bits for pcre_exec()
+        The unused bits of the options argument for pcre_exec() must  be  zero.
+        The   only  bits  that  may  be  set  are  PCRE_ANCHORED,  PCRE_NOTBOL,
+        PCRE_NOTEOL, PCRE_NOTEMPTY, PCRE_NO_UTF8_CHECK and PCRE_PARTIAL.
-        If  you  already  know that your subject is valid, and you want to skip
+          PCRE_ANCHORED
-        these   checks   for   performance   reasons,   you   can    set    the
-        PCRE_NO_UTF8_CHECK  option  when calling pcre_exec(). You might want to
-        do this for the second and subsequent calls to pcre_exec() if  you  are
-        making  repeated  calls  to  find  all  the matches in a single subject
-        string. However, you should be  sure  that  the  value  of  startoffset
-        points  to  the  start of a UTF-8 character. When PCRE_NO_UTF8_CHECK is
-        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.
-        There are also three further options that can be set only  at  matching
+        The PCRE_ANCHORED option limits pcre_exec() to matching  at  the  first
-        time:
+        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
+        unachored at matching time.
           PCRE_NOTBOL
-        The  first  character  of the string is not the beginning of a line, so
+        This option specifies that first character of the subject string is not
-        the circumflex metacharacter should not match before it.  Setting  this
+        the beginning of a line, so the  circumflex  metacharacter  should  not
-        without  PCRE_MULTILINE  (at  compile  time) causes circumflex never to
+        match  before it. Setting this without PCRE_MULTILINE (at compile time)
-        match.
+        causes  circumflex  never  to  match.  This  option  affects  only  the
+        behaviour of the circumflex metacharacter. It does not affect \A.
           PCRE_NOTEOL
-        The end of the string is not the end of a line, so the dollar metachar-
+        This option specifies that the end of the subject string is not the end
-        acter  should  not  match  it  nor (except in multiline mode) a newline
+        of a line, so the dollar metacharacter should not match it nor  (except
-        immediately before it. Setting this without PCRE_MULTILINE (at  compile
+        in  multiline mode) a newline immediately before it. Setting this with-
-        time) causes dollar never to match.
+        out PCRE_MULTILINE (at compile time) causes dollar never to match. This
+        option  affects only the behaviour of the dollar metacharacter. It does
+        not affect \Z or \z.
           PCRE_NOTEMPTY
         An empty string is not considered to be a valid match if this option is
-        set. If there are alternatives in the pattern, they are tried.  If  all
+        set.  If  there are alternatives in the pattern, they are tried. If all
-        the  alternatives  match  the empty string, the entire match fails. For
+        the alternatives match the empty string, the entire  match  fails.  For
         example, if the pattern
           a?b?
-        is applied to a string not beginning with "a" or "b",  it  matches  the
+        is  applied  to  a string not beginning with "a" or "b", it matches the
-        empty  string at the start of the subject. With PCRE_NOTEMPTY set, this
+        empty string at the start of the subject. With PCRE_NOTEMPTY set,  this
         match is not valid, so PCRE searches further into the string for occur-
         rences of "a" or "b".
         Perl has no direct equivalent of PCRE_NOTEMPTY, but it does make a spe-
-        cial case of a pattern match of the empty  string  within  its  split()
+        cial  case  of  a  pattern match of the empty string within its split()
-        function,  and  when  using  the /g modifier. It is possible to emulate
+        function, and when using the /g modifier. It  is  possible  to  emulate
         Perl's behaviour after matching a null string by first trying the match
-        again at the same offset with PCRE_NOTEMPTY set, and then if that fails
+        again at the same offset with PCRE_NOTEMPTY and PCRE_ANCHORED, and then
-        by advancing the starting offset (see below)  and  trying  an  ordinary
+        if  that  fails by advancing the starting offset (see below) and trying
-        match again.
+        an ordinary match again. There is some code that demonstrates how to do
+        this in the pcredemo.c sample program.
+          PCRE_NO_UTF8_CHECK
+        When PCRE_UTF8 is set at compile time, the validity of the subject as a
+        UTF-8 string is automatically checked when pcre_exec() is  subsequently
+        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
+        of bytes is found, pcre_exec() returns the error PCRE_ERROR_BADUTF8. If
+        startoffset contains 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
+        PCRE_NO_UTF8_CHECK  option  when calling pcre_exec(). You might want to
+        do this for the second and subsequent calls to pcre_exec() if  you  are
+        making  repeated  calls  to  find  all  the matches in a single subject
+        string. However, you should be  sure  that  the  value  of  startoffset
+        points  to  the  start of a UTF-8 character. When PCRE_NO_UTF8_CHECK is
+        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
+        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
+        partially  matches  the  pattern and the failure to match occurred only
+        because there were not enough subject characters), pcre_exec()  returns
+        PCRE_ERROR_PARTIAL  instead of PCRE_ERROR_NOMATCH. When PCRE_PARTIAL is
+        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
-        length in length, and a starting byte offset in startoffset. Unlike the
+        length in length, and a starting byte offset in startoffset.  In  UTF-8
-        pattern  string,  the  subject  may contain binary zero bytes. When the
+        mode,  the  byte  offset  must point to the start of a UTF-8 character.
-        starting offset is zero, the search for a match starts at the beginning
+        Unlike the pattern string, the subject may contain binary  zero  bytes.
-        of the subject, and this is by far the most common case.
+        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.
-        If the pattern was compiled with the PCRE_UTF8 option, the subject must
-        be a sequence of bytes that is a valid UTF-8 string, and  the  starting
+        A non-zero starting offset is useful when searching for  another  match
-        offset  must point to the beginning of a UTF-8 character. If an invalid
+        in  the same subject by calling pcre_exec() again after a previous suc-
-        UTF-8 string or offset is passed, an error  (either  PCRE_ERROR_BADUTF8
+        cess.  Setting startoffset differs from just passing over  a  shortened
-        or   PCRE_ERROR_BADUTF8_OFFSET)   is   returned,   unless   the  option
+        string  and  setting  PCRE_NOTBOL  in the case of a pattern that begins
-        PCRE_NO_UTF8_CHECK is set,  in  which  case  PCRE's  behaviour  is  not
-        defined.
-        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-
-        cess.   Setting  startoffset differs from just passing over a shortened
-        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
+        string again, but with startoffset set to 4, it finds the second occur-
-        occurrence  of  "iss"  because  it  is able to look behind the starting
+        rence of "iss" because it is able to look behind the starting point  to
-        point to discover that it is preceded by a letter.
+        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 tried. This can only suc-
+        one attempt to match at the given offset is made. This can only succeed
-        ceed if the pattern does not require the match to be at  the  start  of
+        if  the  pattern  does  not require the match to be at the start of the
-        the subject.
+        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. The first two-thirds of the vector is
+        the vector is passed in ovecsize, which must be a non-negative  number.
-        used to pass back captured substrings, each substring using a  pair  of
+        Note: this argument is NOT the size of ovector in bytes.
-        integers.  The  remaining  third  of the vector is used as workspace by
-        pcre_exec() while matching capturing subpatterns, and is not  available
+        The  first  two-thirds of the vector is used to pass back captured sub-
-        for  passing  back  information.  The  length passed in ovecsize should
+        strings, each substring using a pair of integers. The  remaining  third
-        always be a multiple of three. If it is not, it is rounded down.
+        of  the  vector is used as workspace by pcre_exec() while matching cap-
+        turing subpatterns, and is not available for passing back  information.
+        The  length passed in ovecsize should always be a multiple of three. If
+        it is not, it is rounded down.
-        When a match has been successful, information about captured substrings
+        When a match is successful, information about  captured  substrings  is
-        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
         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
-Line 1161 
 MATCHING A PATTERN
+Line 1309 
 MATCHING A PATTERN
         offset values corresponding to the unused subpattern are set to -1.
         If a capturing subpattern is matched repeatedly, it is the last portion
-        of the string that it matched that gets returned.
+        of the string that it matched that is returned.
-        If the vector is too small to hold all the captured substrings,  it  is
+        If the vector is too small to hold all the captured substring  offsets,
-        used as far as possible (up to two-thirds of its length), and the func-
+        it is used as far as possible (up to two-thirds of its length), and the
-        tion returns a value of zero. In particular, if the  substring  offsets
+        function returns a value of zero. In particular, if the substring  off-
-        are  not  of interest, pcre_exec() may be called with ovector passed as
+        sets are not of interest, pcre_exec() may be called with ovector passed
-        NULL and ovecsize as zero. However, if the pattern contains back refer-
+        as NULL and ovecsize as zero. However, if  the  pattern  contains  back
-        ences  and  the  ovector  isn't big enough to remember the related sub-
+        references  and  the  ovector is not big enough to remember the related
-        strings, 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.
         Note  that  pcre_info() can be used to find out how many capturing sub-
-Line 1177 
 MATCHING A PATTERN
+Line 1325 
 MATCHING A PATTERN
         that  will  allow for n captured substrings, in addition to the offsets
         of the substring matched by the whole pattern, is (n+1)*3.
+    Return values from pcre_exec()
         If pcre_exec() fails, it returns a negative number. The  following  are
         defined in the header file:
-Line 1196 
 MATCHING A PATTERN
+Line 1346 
 MATCHING A PATTERN
           PCRE_ERROR_BADMAGIC       (-4)
         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. This is the error
+        to catch the case when it is passed a junk pointer and to detect when a
-        it gives when the magic number isn't present.
+        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
+        gives when the magic number is not present.
           PCRE_ERROR_UNKNOWN_NODE   (-5)
-Line 1211 
 MATCHING A PATTERN
+Line 1363 
 MATCHING A PATTERN
         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
         purpose.  If the call via pcre_malloc() fails, this error is given. The
-        memory is freed at the end of matching.
+        memory is automatically freed at the end of matching.
           PCRE_ERROR_NOSUBSTRING    (-7)
-Line 1242 
 MATCHING A PATTERN
+Line 1394 
 MATCHING A PATTERN
         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
+        pcrepartial documentation for details of partial matching.
+          PCRE_ERROR_BAD_PARTIAL (-13)
+        The PCRE_PARTIAL option was used with  a  compiled  pattern  containing
+        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
+        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.
  EXTRACTING CAPTURED SUBSTRINGS BY NUMBER
-Line 1256 
 EXTRACTING CAPTURED SUBSTRINGS BY NUMBER
+Line 1428 
 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
+        substrings. A substring  that  contains  a  binary  zero  is  correctly
-        extracted and has a further zero added on the end, but  the  result  is
+        extracted  and  has  a further zero added on the end, but the result is
         not, of course, a C string.
-        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 which 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
+        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 size of the vector divided by three.
+        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, while
+        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
           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 which is obtained via pcre_malloc.  The  address
+        single block of memory that is obtained via pcre_malloc. The address of
-        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
           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
+        The  two convenience functions pcre_free_substring() and pcre_free_sub-
-        pcre_free_substring_list() can be used to free the memory returned by a
+        string_list() can be used to free the memory  returned  by  a  previous
-        previous call  of  pcre_get_substring()  or  pcre_get_substring_list(),
+        call  of  pcre_get_substring()  or  pcre_get_substring_list(),  respec-
-        respectively. 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  which  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
-        vided.
+        provided.
  EXTRACTING CAPTURED SUBSTRINGS BY NAME
+        int pcre_get_stringnumber(const pcre *code,
+             const char *name);
         int pcre_copy_named_substring(const pcre *code,
              const char *subject, int *ovector,
              int stringcount, const char *stringname,
              char *buffer, int buffersize);
-        int pcre_get_stringnumber(const pcre *code,
-             const char *name);
         int pcre_get_named_substring(const pcre *code,
              const char *subject, int *ovector,
              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.  This  can  be  done by calling pcre_get_stringnumber(). The first
+        ber.  For example, for this pattern
-        argument is the compiled pattern, and the second is the name. For exam-
-        ple, for this pattern
+          (a+)b(?<xxx>\d+)...
-          ab(?<xxx>\d+)...
+        the number of the subpattern called "xxx" is 2. You can find the number
+        from the name by calling pcre_get_stringnumber(). The first argument is
-        the  number  of the subpattern called "xxx" is 1. Given the number, you
+        the compiled pattern, and the second is the  name.  The  yield  of  the
-        can then extract the substring directly, or use one  of  the  functions
+        function  is  the  subpattern number, or PCRE_ERROR_NOSUBSTRING (-7) if
-        described  in the previous section. For convenience, there are also two
+        there is no subpattern of that name.
-        functions that do the whole job.
+        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
-        pcre_get_named_substring() are the same as those for the functions that
+        pcre_get_named_substring()  are  the  same  as  those for the similarly
-        extract by number, and so are not re-described here. There are just two
+        named functions that extract by number. As these are described  in  the
-        differences.
+        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.
- Last updated: 09 December 2003
+ Last updated: 09 September 2004
- Copyright (c) 1997-2003 University of Cambridge.
+ Copyright (c) 1997-2004 University of Cambridge.
  -----------------------------------------------------------------------------
  PCRE(3)                                                                PCRE(3)
-Line 1392 
 PCRE CALLOUTS
+Line 1568 
 PCRE CALLOUTS
         default value is zero.  For  example,  this  pattern  has  two  callout
         points:
-          (?C1)abc(?C2)def
+          (?C1)eabc(?C2)def
-        During matching, when PCRE reaches a callout point (and pcre_callout is
+        If  the  PCRE_AUTO_CALLOUT  option  bit  is  set when pcre_compile() is
-        set), the external function is called. Its only argument is  a  pointer
+        called, PCRE automatically  inserts  callouts,  all  with  number  255,
-        to a pcre_callout block. This contains the following variables:
+        before  each  item in the pattern. For example, if PCRE_AUTO_CALLOUT is
+        used with the pattern
+          A(\d{2}|--)
+        it is processed as if it were
+        (?C255)A(?C255)((?C255)\d{2}(?C255)|(?C255)-(?C255)-(?C255))(?C255)
+        Notice that there is a callout before and after  each  parenthesis  and
+        alternation  bar.  Automatic  callouts  can  be  used  for tracking the
+        progress of pattern matching. The pcretest command has an  option  that
+        sets  automatic callouts; when it is used, the output indicates how the
+        pattern is matched. This is useful information when you are  trying  to
+        optimize the performance of a particular pattern.
+ MISSING CALLOUTS
+        You  should  be  aware  that,  because of optimizations in the way PCRE
+        matches patterns, callouts sometimes do not happen. For example, if the
+        pattern is
+          ab(?C4)cd
+        PCRE knows that any matching string must contain the letter "d". If the
+        subject string is "abyz", the lack of "d" means that  matching  doesn't
+        ever  start,  and  the  callout is never reached. However, with "abyd",
+        though the result is still no match, the callout is obeyed.
+ THE CALLOUT INTERFACE
+        During matching, when PCRE reaches a callout point, the external  func-
+        tion  defined  by pcre_callout is called (if it is set). The only argu-
+        ment is a pointer to a pcre_callout block. This structure contains  the
+        following fields:
           int          version;
           int          callout_number;
-Line 1408 
 PCRE CALLOUTS
+Line 1620 
 PCRE CALLOUTS
           int          capture_top;
           int          capture_last;
           void        *callout_data;
+          int          pattern_position;
+          int          next_item_length;
         The  version  field  is an integer containing the version number of the
-        block format. The current version  is  zero.  The  version  number  may
+        block format. The initial version was 0; the current version is 1.  The
-        change  in  future if additional fields are added, but the intention is
+        version  number  will  change  again in future if additional fields are
-        never to remove any of the existing fields.
+        added, but the intention is never to remove any of the existing fields.
-        The callout_number field contains the number of the  callout,  as  com-
+        The  callout_number  field  contains the number of the callout, as com-
-        piled into the pattern (that is, the number after ?C).
+        piled into the pattern (that is, the number after ?C for  manual  call-
+        outs, and 255 for automatically generated callouts).
         The  offset_vector field is a pointer to the vector of offsets that was
         passed by the caller to pcre_exec(). The contents can be  inspected  in
         order  to extract substrings that have been matched so far, in the same
         way as for extracting substrings after a match has completed.
-        The subject and subject_length fields contain copies  the  values  that
+        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 current match attempt started. If the pattern is not anchored,  the
-        callout  function  may  be  called several times for different starting
+        callout function may be called several times from the same point in the
-        points.
+        pattern for different starting points in the subject.
         The current_position field contains the offset within  the  subject  of
         the current match pointer.
         The  capture_top field contains one more than the number of the highest
-        numbered  captured  substring  so  far.  If  no  substrings  have  been
+        numbered captured substring so far. If no  substrings  have  been  cap-
-        captured, the value of capture_top is one.
+        tured, the value of capture_top is one.
         The  capture_last  field  contains the number of the most recently cap-
-        tured substring.
+        tured substring. If no substrings have been captured, its value is  -1.
-        The callout_data field contains a value that is passed  to  pcre_exec()
+        The  callout_data  field contains a value that is passed to pcre_exec()
-        by  the  caller specifically so that it can be passed back in callouts.
+        by the caller specifically so that it can be passed back  in  callouts.
-        It is passed in the pcre_callout field of the  pcre_extra  data  struc-
+        It  is  passed  in the pcre_callout field of the pcre_extra data struc-
-        ture.  If  no  such  data  was  passed,  the value of callout_data in a
+        ture. If no such data was  passed,  the  value  of  callout_data  in  a
-        pcre_callout block is NULL. There is a description  of  the  pcre_extra
+        pcre_callout  block  is  NULL. There is a description of the pcre_extra
         structure in the pcreapi documentation.
+        The pattern_position field is present from version 1 of the  pcre_call-
+        out structure. It contains the offset to the next item to be matched in
+        the pattern string.
+        The next_item_length field is present from version 1 of the  pcre_call-
+        out structure. It contains the length of the next item to be matched in
+        the pattern string. When the callout immediately precedes  an  alterna-
+        tion  bar, a closing parenthesis, or the end of the pattern, the length
+        is zero. When the callout precedes an opening parenthesis,  the  length
+        is that of the entire subpattern.
+        The  pattern_position  and next_item_length fields are intended to help
+        in distinguishing between different automatic callouts, which all  have
+        the same callout number. However, they are set for all callouts.
  RETURN VALUES
-        The callout function returns an integer. If the value is zero, matching
+        The  external callout function returns an integer to PCRE. If the value
-        proceeds as normal. If the value is greater than zero,  matching  fails
+        is zero, matching proceeds as normal. If  the  value  is  greater  than
-        at the current point, but backtracking to test other possibilities goes
+        zero,  matching  fails  at  the current point, but backtracking to test
-        ahead, just as if a lookahead assertion had failed.  If  the  value  is
+        other matching possibilities goes ahead, just as if a lookahead  asser-
-        less  than  zero,  the  match is abandoned, and pcre_exec() returns the
+        tion  had  failed.  If  the value is less than zero, the match is aban-
-        value.
+        doned, and pcre_exec() returns the negative value.
         Negative  values  should  normally  be   chosen   from   the   set   of
         PCRE_ERROR_xxx values. In particular, PCRE_ERROR_NOMATCH forces a stan-
-Line 1464 
 RETURN VALUES
+Line 1693 
 RETURN VALUES
         reserved  for  use  by callout functions; it will never be used by PCRE
         itself.
- Last updated: 21 January 2003
+ Last updated: 09 September 2004
- Copyright (c) 1997-2003 University of Cambridge.
+ Copyright (c) 1997-2004 University of Cambridge.
  -----------------------------------------------------------------------------
  PCRE(3)                                                                PCRE(3)
-Line 1475 
 PCRE(3)
+Line 1704 
 PCRE(3)
  NAME
         PCRE - Perl-compatible regular expressions
- DIFFERENCES FROM PERL
+ 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  with
-Line 1498 
 DIFFERENCES FROM PERL
+Line 1727 
 DIFFERENCES FROM PERL
 . Though binary zero characters are supported in the  subject  string,
         they are not allowed in a pattern string because it is passed as a nor-
-        mal C string, terminated by zero. The escape sequence "\0" can be  used
+        mal C string, terminated by zero. The escape sequence \0 can be used in
-        in the pattern to represent a binary zero.
+        the pattern to represent a binary zero.
 .  The  following Perl escape sequences are not supported: \l, \u, \L,
-        \U, \P, \p, \N, and \X. In fact these are implemented by Perl's general
+        \U, and \N. In fact these are implemented by Perl's general string-han-
-        string-handling and are not part of its pattern matching engine. If any
+        dling  and are not part of its pattern matching engine. If any of these
-        of these are encountered by PCRE, an error is generated.
+        are encountered by PCRE, an error is generated.
-. PCRE does support the \Q...\E escape for quoting substrings. Charac-
+. The Perl escape sequences \p, \P, and \X are supported only if  PCRE
-        ters  in  between  are  treated as literals. This is slightly different
+        is  built  with Unicode character property support. The properties that
-        from Perl in that $ and @ are  also  handled  as  literals  inside  the
+        can be tested with \p and \P are limited to the general category  prop-
-        quotes.  In Perl, they cause variable interpolation (but of course PCRE
+        erties such as Lu and Nd.
+. PCRE does support the \Q...\E escape for quoting substrings. Charac-
+        ters in between are treated as literals.  This  is  slightly  different
+        from  Perl  in  that  $  and  @ are also handled as literals inside the
+        quotes. In Perl, they cause variable interpolation (but of course  PCRE
         does not have variables). Note the following examples:
             Pattern            PCRE matches      Perl matches
-Line 1519 
 DIFFERENCES FROM PERL
+Line 1753 
 DIFFERENCES FROM PERL
             \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.
 . Fairly obviously, PCRE does not support the (?{code}) and (?p{code})
-        constructions. However, there is some experimental support  for  recur-
+        constructions.  However,  there is support for recursive patterns using
-        sive  patterns  using the non-Perl items (?R), (?number) and (?P>name).
+        the non-Perl items (?R),  (?number),  and  (?P>name).  Also,  the  PCRE
-        Also, the PCRE "callout" feature allows  an  external  function  to  be
+        "callout"  feature allows an external function to be called during pat-
-        called during pattern matching.
+        tern matching. See the pcrecallout documentation for details.
-.  There  are some differences that are concerned with the settings of
+. There are some differences that are concerned with the  settings  of
-        captured strings when part of  a  pattern  is  repeated.  For  example,
+        captured  strings  when  part  of  a  pattern is repeated. For example,
-        matching  "aba"  against  the  pattern  /^(a(b)?)+$/  in Perl leaves $2
+        matching "aba" against the  pattern  /^(a(b)?)+$/  in  Perl  leaves  $2
         unset, but in PCRE it is set to "b".
-. PCRE  provides  some  extensions  to  the  Perl  regular  expression
+. PCRE provides some extensions to the Perl regular expression facil-
-        facilities:
+        ities:
-        (a)  Although  lookbehind  assertions  must match fixed length strings,
+        (a) Although lookbehind assertions must  match  fixed  length  strings,
         each alternative branch of a lookbehind assertion can match a different
         length of string. Perl requires them all to have the same length.
-        (b)  If PCRE_DOLLAR_ENDONLY is set and PCRE_MULTILINE is not set, the $
+        (b) If PCRE_DOLLAR_ENDONLY is set and PCRE_MULTILINE is not set, the  $
         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.
-        (d)  If  PCRE_UNGREEDY is set, the greediness of the repetition quanti-
+        (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-
         lowed by a question mark they are.
-        (e)  PCRE_ANCHORED  can  be used to force a pattern to be tried only at
+        (e) PCRE_ANCHORED can be used at matching time to force a pattern to be
-        the first matching position in the subject string.
+        tried only at the first matching position in the subject string.
-        (f) The PCRE_NOTBOL, PCRE_NOTEOL, PCRE_NOTEMPTY, and  PCRE_NO_AUTO_CAP-
+        (f)  The PCRE_NOTBOL, PCRE_NOTEOL, PCRE_NOTEMPTY, and PCRE_NO_AUTO_CAP-
         TURE options for pcre_exec() have no Perl equivalents.
-        (g)  The (?R), (?number), and (?P>name) constructs allows for recursive
+        (g) The (?R), (?number), and (?P>name) constructs allows for  recursive
-        pattern matching (Perl can do  this  using  the  (?p{code})  construct,
+        pattern  matching  (Perl  can  do  this using the (?p{code}) construct,
         which PCRE cannot support.)
-        (h)  PCRE supports named capturing substrings, using the Python syntax.
+        (h) PCRE supports named capturing substrings, using the Python  syntax.
-        (i) PCRE supports the possessive quantifier  "++"  syntax,  taken  from
+        (i)  PCRE  supports  the  possessive quantifier "++" syntax, taken from
         Sun's Java package.
         (j) The (R) condition, for testing recursion, is a PCRE extension.
         (k) The callout facility is PCRE-specific.
- Last updated: 09 December 2003
+        (l) The partial matching facility is PCRE-specific.
- Copyright (c) 1997-2003 University of Cambridge.
+        (m) Patterns compiled by PCRE can be saved and re-used at a later time,
+        even on different hosts that have the other endianness.
+ Last updated: 09 September 2004
+ Copyright (c) 1997-2004 University of Cambridge.
  -----------------------------------------------------------------------------
  PCRE(3)                                                                PCRE(3)
-Line 1584 
 PCRE REGULAR EXPRESSION DETAILS
+Line 1823 
 PCRE REGULAR EXPRESSION DETAILS
         The  syntax  and semantics of the regular expressions supported by PCRE
         are described below. Regular expressions are also described in the Perl
-        documentation  and in a number of other books, some of which have copi-
+        documentation  and  in  a  number  of books, some of which have copious
-        ous examples. Jeffrey Friedl's "Mastering  Regular  Expressions",  pub-
+        examples.  Jeffrey Friedl's "Mastering Regular Expressions",  published
-        lished  by  O'Reilly, covers them in great detail. The description here
+        by  O'Reilly, covers regular expressions in great detail. This descrip-
-        is intended as reference documentation.
+        tion of PCRE's regular expressions is intended as reference material.
-        The basic operation of PCRE is on strings of bytes. However,  there  is
+        The original operation of PCRE was on strings of  one-byte  characters.
-        also  support for UTF-8 character strings. To use this support you must
+        However,  there is now also support for UTF-8 character strings. To use
-        build PCRE to include UTF-8 support, and then call pcre_compile()  with
+        this, you must build PCRE to  include  UTF-8  support,  and  then  call
-        the  PCRE_UTF8  option.  How  this affects the pattern matching is men-
+        pcre_compile()  with  the  PCRE_UTF8  option.  How this affects pattern
-        tioned in several places below. There is also a summary of  UTF-8  fea-
+        matching is mentioned in several places below. There is also a  summary
-        tures in the section on UTF-8 support in the main pcre page.
+        of  UTF-8  features  in  the  section on UTF-8 support in the main pcre
+        page.
-        A  regular  expression  is  a pattern that is matched against a subject
-        string from left to right. Most characters stand for  themselves  in  a
+        A regular expression is a pattern that is  matched  against  a  subject
-        pattern,  and  match  the corresponding characters in the subject. As a
+        string  from  left  to right. Most characters stand for themselves in 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.  The
+        matches  a portion of a subject string that is identical to itself. The
         power of regular expressions comes from the ability to include alterna-
-        tives and repetitions in the pattern. These are encoded in the  pattern
+        tives  and repetitions in the pattern. These are encoded in the pattern
-        by  the  use  of meta-characters, which do not stand for themselves but
+        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 meta-characters: 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 in square brackets. Outside  square  brackets,  the
+        that  are  recognized  in square brackets. Outside square brackets, the
-        meta-characters are as follows:
+        metacharacters are as follows:
           \      general escape character with several uses
           ^      assert start of string (or line, in multiline mode)
-Line 1630 
 PCRE REGULAR EXPRESSION DETAILS
+Line 1870 
 PCRE REGULAR EXPRESSION DETAILS
                  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 meta-characters are:
+        class". In a character class the only metacharacters are:
           \      general escape character
           ^      negate the class, but only if the first character
-Line 1640 
 PCRE REGULAR EXPRESSION DETAILS
+Line 1880 
 PCRE REGULAR EXPRESSION DETAILS
                    syntax)
           ]      terminates the character class
-        The following sections describe the use of each of the meta-characters.
+        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-alphameric 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 meta-character, so it  is
+        character  would  otherwise be interpreted as a metacharacter, so it is
-        always  safe to precede a non-alphameric with backslash to specify that
+        always safe to precede a non-alphanumeric  with  backslash  to  specify
-        it stands for itself. In particular, if you want to match a  backslash,
+        that  it stands for itself. In particular, if you want to match a back-
-        you write \\.
+        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 character are ignored.
-        An escaping backslash can be used to include a whitespace or #  charac-
+        An  escaping backslash can be used to include a whitespace or # charac-
         ter 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 1676 
 BACKSLASH
+Line 1916 
 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)
-Line 1697 
 BACKSLASH
+Line 1939 
 BACKSLASH
           \xhh      character with hex code hh
           \x{hhh..} character with hex code hhh... (UTF-8 mode only)
-        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). In UTF-8 mode, any number of hexadecimal dig-
+        in upper or lower case). In UTF-8 mode, any number of hexadecimal  dig-
-        its may appear between \x{ and }, but the value of the  character  code
+        its  may  appear between \x{ and }, but the value of the character code
-        must  be  less  than  2**31  (that is, the maximum hexadecimal value is
+        must be less than 2**31 (that is,  the  maximum  hexadecimal  value  is
-FFFFFFF). If characters other than hexadecimal digits  appear  between
+FFFFFFF).  If  characters other than hexadecimal digits appear between
-        \x{  and }, or if there is no terminating }, this form of escape is not
+        \x{ and }, or if there is no terminating }, this form of escape is  not
         recognized. Instead, the initial \x will be interpreted as a basic hex-
-        adecimal escape, with no following digits, giving a byte whose value is
+        adecimal escape, with no following digits,  giving  a  character  whose
-        zero.
+        value is zero.
         Characters whose value is less than 256 can be defined by either of the
-        two  syntaxes for \x when PCRE is in UTF-8 mode. There is no difference
+        two syntaxes for \x when PCRE is in UTF-8 mode. There is no  difference
-        in the way they are handled. For example, \xdc is exactly the  same  as
+        in  the  way they are handled. For example, \xdc is exactly the same as
         \x{dc}.
-        After  \0  up  to  two further octal digits are read. In both cases, if
+        After \0 up to two further octal digits are read.  In  both  cases,  if
-        there are fewer than two digits, just those that are present are  used.
+        there  are fewer than two digits, just those that are present are used.
-        Thus  the sequence \0\x\07 specifies two binary zeros followed by a BEL
+        Thus the sequence \0\x\07 specifies two binary zeros followed by a  BEL
-        character (code value 7). Make sure you supply  two  digits  after  the
+        character  (code  value  7).  Make sure you supply two digits after the
-        initial zero if the character that follows is itself an octal digit.
+        initial zero if the pattern character that follows is itself  an  octal
+        digit.
         The handling of a backslash followed by a digit other than 0 is compli-
         cated.  Outside a character class, PCRE reads it and any following dig-
-Line 1758 
 BACKSLASH
+Line 2001 
 BACKSLASH
         All the sequences that define a single byte value  or  a  single  UTF-8
         character (in UTF-8 mode) can be used both inside and outside character
         classes. In addition, inside a character  class,  the  sequence  \b  is
-        interpreted  as  the  backspace character (hex 08). Outside a character
+        interpreted as the backspace character (hex 08), and the sequence \X is
-        class it has a different meaning (see below).
+        interpreted as the character "X".  Outside  a  character  class,  these
+        sequences have different meanings (see below).
+    Generic character types
-        The third use of backslash is for specifying generic character types:
+        The  third  use of backslash is for specifying generic character types.
+        The following are always recognized:
           \d     any decimal digit
           \D     any character that is not a decimal digit
-Line 1774 
 BACKSLASH
+Line 2021 
 BACKSLASH
         into  two disjoint sets. Any given character matches one, and only one,
         of each pair.
-        In UTF-8 mode, characters with values greater than 255 never match  \d,
+        These character type sequences can appear both inside and outside char-
-        \s, or \w, and always match \D, \S, and \W.
+        acter  classes.  They each match one character of the appropriate type.
+        If the current matching point is at the end of the subject string,  all
+        of them fail, since there is no character to match.
         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).
-        A  "word" character is any letter or digit or the underscore character,
+        A "word" character is an underscore or any character less than 256 that
-        that is, any character which can be part of a Perl "word". The  defini-
+        is a letter or digit. The definition of  letters  and  digits  is  con-
-        tion  of  letters  and digits is controlled by PCRE's character tables,
+        trolled  by PCRE's low-valued character tables, and may vary if locale-
-        and may vary if locale- specific matching is taking place (see  "Locale
+        specific matching is taking place (see "Locale support" in the  pcreapi
-        support"  in  the  pcreapi  page).  For  example,  in the "fr" (French)
+        page).  For  example,  in  the  "fr_FR" (French) locale, some character
-        locale, some character codes greater than 128  are  used  for  accented
+        codes greater than 128 are used for accented  letters,  and  these  are
-        letters, and these are matched by \w.
+        matched by \w.
+        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.
+    Unicode character properties
+        When PCRE is built with Unicode character property support, three addi-
+        tional escape sequences to match generic character types are  available
+        when UTF-8 mode is selected. They 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
+        general category properties. Each character has exactly one such  prop-
+        erty,  specified  by  a two-letter abbreviation. For compatibility with
+        Perl, negation can be 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
+        properties that start with that letter. In this case, in the absence of
+        negation, the curly brackets in the escape sequence are optional; these
+        two examples have the same effect:
+          \p{L}
+          \pL
+        The following property codes are supported:
+          C     Other
+          Cc    Control
+          Cf    Format
+          Cn    Unassigned
+          Co    Private use
+          Cs    Surrogate
+          L     Letter
+          Ll    Lower case letter
+          Lm    Modifier letter
+          Lo    Other letter
+          Lt    Title case letter
+          Lu    Upper case letter
+          M     Mark
+          Mc    Spacing mark
+          Me    Enclosing mark
+          Mn    Non-spacing mark
+          N     Number
+          Nd    Decimal number
+          Nl    Letter number
+          No    Other number
+          P     Punctuation
+          Pc    Connector punctuation
+          Pd    Dash punctuation
+          Pe    Close punctuation
+          Pf    Final punctuation
+          Pi    Initial punctuation
+          Po    Other punctuation
+          Ps    Open punctuation
+          S     Symbol
+          Sc    Currency symbol
+          Sk    Modifier symbol
+          Sm    Mathematical symbol
+          So    Other symbol
+          Z     Separator
+          Zl    Line separator
+          Zp    Paragraph separator
+          Zs    Space separator
+        Extended  properties such as "Greek" or "InMusicalSymbols" are not sup-
+        ported by PCRE.
+        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
+        extended Unicode sequence. \X is equivalent to
+          (?>\PM\pM*)
+        That is, it matches a character without the "mark"  property,  followed
+        by  zero  or  more  characters with the "mark" property, and treats the
+        sequence as an atomic group (see below).  Characters  with  the  "mark"
+        property are typically accents that affect the preceding character.
+        Matching  characters  by Unicode property is not fast, because PCRE has
+        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.
-        These character type sequences can appear both inside and outside char-
+    Simple assertions
-        acter classes. They each match one character of the  appropriate  type.
-        If  the current matching point is at the end of the subject string, all
-        of them fail, since there is no character to match.
         The fourth use of backslash is for certain simple assertions. An asser-
         tion  specifies a condition that has to be met at a particular point in
         a match, without consuming any characters from the subject string.  The
         use  of subpatterns for more complicated assertions is described below.
-        The backslashed assertions are
+        The backslashed assertions are:
           \b     matches at a word boundary
           \B     matches when not at a word boundary
-Line 1817 
 BACKSLASH
+Line 2159 
 BACKSLASH
         string if the first or last character matches \w, respectively.
         The  \A,  \Z,  and \z assertions differ from the traditional circumflex
-        and dollar (described below) in that they only ever match at  the  very
+        and dollar (described in the next section) in that they only ever match
-        start  and  end  of the subject string, whatever options are set. Thus,
+        at  the  very start and end of the subject string, whatever options are
-        they are independent of multiline mode.
+        set. Thus, they are independent of multiline mode. These  three  asser-
+        tions are not affected by the PCRE_NOTBOL or PCRE_NOTEOL options, which
-        They are not affected by the PCRE_NOTBOL or PCRE_NOTEOL options. If the
+        affect only the behaviour of the circumflex and dollar  metacharacters.
-        startoffset argument of pcre_exec() is non-zero, indicating that match-
+        However,  if the startoffset argument of pcre_exec() is non-zero, indi-
-        ing is to start at a point other than the beginning of the subject,  \A
+        cating that matching is to start at a point other than the beginning of
-        can  never  match.  The difference between \Z and \z is that \Z matches
+        the  subject,  \A  can never match. The difference between \Z and \z is
-        before a newline that is the last character of the string as well as at
+        that \Z matches before a newline that is  the  last  character  of  the
-        the end of the string, whereas \z matches only at the end.
+        string  as well as at the end of the string, whereas \z matches only at
+        the end.
-        The  \G assertion is true only when the current matching position is at
-        the start point of the match, as specified by the startoffset  argument
+        The \G assertion is true only when the current matching position is  at
-        of  pcre_exec().  It  differs  from \A when the value of startoffset is
+        the  start point of the match, as specified by the startoffset argument
-        non-zero. By calling pcre_exec() multiple times with appropriate  argu-
+        of pcre_exec(). It differs from \A when the  value  of  startoffset  is
+        non-zero.  By calling pcre_exec() multiple times with appropriate argu-
         ments, you can mimic Perl's /g option, and it is in this kind of imple-
         mentation where \G can be useful.
-        Note, however, that PCRE's interpretation of \G, as the  start  of  the
+        Note,  however,  that  PCRE's interpretation of \G, as the start of the
         current match, is subtly different from Perl's, which defines it as the
-        end of the previous match. In Perl, these can  be  different  when  the
+        end  of  the  previous  match. In Perl, these can be different when the
-        previously  matched  string was empty. Because PCRE does just one match
+        previously matched string was empty. Because PCRE does just  one  match
         at a time, it cannot reproduce this behaviour.
-        If all the alternatives of a pattern begin with \G, the  expression  is
+        If  all  the alternatives of a pattern begin with \G, the expression is
         anchored to the starting match position, and the "anchored" flag is set
         in the compiled regular expression.
-Line 1849 
 BACKSLASH
+Line 2192 
 BACKSLASH
  CIRCUMFLEX AND DOLLAR
         Outside a character class, in the default matching mode, the circumflex
-        character  is  an  assertion which is true only if the current matching
+        character is an assertion that is true only  if  the  current  matching
-        point is at the start of the subject string. If the  startoffset  argu-
+        point  is  at the start of the subject string. If the startoffset argu-
-        ment  of  pcre_exec()  is  non-zero,  circumflex can never match if the
+        ment of pcre_exec() is non-zero, circumflex  can  never  match  if  the
-        PCRE_MULTILINE option is unset. Inside a  character  class,  circumflex
+        PCRE_MULTILINE  option  is  unset. Inside a character class, circumflex
         has an entirely different meaning (see below).
-        Circumflex  need  not be the first character of the pattern if a number
+        Circumflex need not be the first character of the pattern if  a  number
-        of alternatives are involved, but it should be the first thing in  each
+        of  alternatives are involved, but it should be the first thing in each
-        alternative  in  which  it appears if the pattern is ever to match that
+        alternative in which it appears if the pattern is ever  to  match  that
-        branch. If all possible alternatives start with a circumflex, that  is,
+        branch.  If all possible alternatives start with a circumflex, that is,
-        if  the  pattern  is constrained to match only at the start of the sub-
+        if the pattern is constrained to match only at the start  of  the  sub-
-        ject, it is said to be an "anchored" pattern.  (There  are  also  other
+        ject,  it  is  said  to be an "anchored" pattern. (There are also other
         constructs that can cause a pattern to be anchored.)
-        A  dollar  character  is an assertion which is true only if the current
+        A dollar character is an assertion that is true  only  if  the  current
-        matching point is at the end of  the  subject  string,  or  immediately
+        matching  point  is  at  the  end of the subject string, or immediately
         before a newline character that is the last character in the string (by
-        default). Dollar need not be the last character of  the  pattern  if  a
+        default).  Dollar  need  not  be the last character of the pattern if a
-        number  of alternatives are involved, but it should be the last item in
+        number of alternatives are involved, but it should be the last item  in
-        any branch in which it appears.  Dollar has no  special  meaning  in  a
+        any  branch  in  which  it appears.  Dollar has no special meaning in a
         character class.
-        The  meaning  of  dollar  can be changed so that it matches only at the
+        The meaning of dollar can be changed so that it  matches  only  at  the
-        very end of the string, by setting the  PCRE_DOLLAR_ENDONLY  option  at
+        very  end  of  the string, by setting the PCRE_DOLLAR_ENDONLY option at
         compile time. This does not affect the \Z assertion.
         The meanings of the circumflex and dollar characters are changed if the
         PCRE_MULTILINE option is set. When this is the case, they match immedi-
-        ately  after  and  immediately  before  an  internal newline character,
+        ately after and  immediately  before  an  internal  newline  character,
-        respectively, in addition to matching at the start and end of the  sub-
+        respectively,  in addition to matching at the start and end of the sub-
-        ject  string.  For  example,  the  pattern  /^abc$/ matches the subject
+        ject string. For example,  the  pattern  /^abc$/  matches  the  subject
-        string "def\nabc" in multiline mode, but not  otherwise.  Consequently,
+        string  "def\nabc"  (where \n represents a newline character) in multi-
-        patterns  that  are  anchored  in single line mode because all branches
+        line mode, but not otherwise.  Consequently, patterns that are anchored
-        start with ^ are not anchored in multiline mode, and a match  for  cir-
+        in  single line mode because all branches start with ^ are not anchored
-        cumflex  is  possible  when  the startoffset argument of pcre_exec() is
+        in multiline mode, and a match for  circumflex  is  possible  when  the
-        non-zero. The PCRE_DOLLAR_ENDONLY option is ignored  if  PCRE_MULTILINE
+        startoffset   argument   of  pcre_exec()  is  non-zero.  The  PCRE_DOL-
-        is set.
+        LAR_ENDONLY option is ignored if PCRE_MULTILINE is set.
-        Note  that  the sequences \A, \Z, and \z can be used to match the start
+        Note that the sequences \A, \Z, and \z can be used to match  the  start
-        and end of the subject in both modes, and if all branches of a  pattern
+        and  end of the subject in both modes, and if all branches of a pattern
-        start  with  \A it is always anchored, whether PCRE_MULTILINE is set or
+        start with \A it is always anchored, whether PCRE_MULTILINE is  set  or
         not.
  FULL STOP (PERIOD, DOT)
         Outside a character class, a dot in the pattern matches any one charac-
-        ter  in  the  subject,  including a non-printing character, but not (by
+        ter in the subject, including a non-printing  character,  but  not  (by
-        default) newline.  In UTF-8 mode, a dot matches  any  UTF-8  character,
+        default)  newline.   In  UTF-8 mode, a dot matches any UTF-8 character,
-        which  might  be  more than one byte long, except (by default) for new-
+        which might be more than one byte long, except (by default) newline. If
-        line. If the PCRE_DOTALL option is set, dots match  newlines  as  well.
+        the  PCRE_DOTALL  option  is set, dots match newlines as well. The han-
-        The  handling of dot is entirely independent of the handling of circum-
+        dling of dot is entirely independent of the handling of circumflex  and
-        flex and dollar, the only relationship being  that  they  both  involve
+        dollar,  the  only  relationship  being  that they both involve newline
-        newline characters. Dot has no special meaning in a character class.
+        characters. Dot has no special meaning in a character class.
  MATCHING A SINGLE BYTE
         Outside a character class, the escape sequence \C matches any one byte,
-        both in and out of UTF-8 mode. Unlike a dot, it always matches  a  new-
+        both  in  and  out of UTF-8 mode. Unlike a dot, it can match a newline.
-        line.  The  feature  is  provided  in Perl in order to match individual
+        The feature is provided in Perl in order to match individual  bytes  in
-        bytes in UTF-8 mode.  Because it breaks up UTF-8 characters into  indi-
+        UTF-8  mode.  Because  it  breaks  up  UTF-8 characters into individual
-        vidual  bytes,  what  remains  in  the  string may be a malformed UTF-8
+        bytes, what remains in the string may be a malformed UTF-8 string.  For
-        string. For this reason it is best avoided.
+        this reason, the \C escape sequence is best avoided.
-        PCRE does not allow \C to appear in lookbehind assertions (see  below),
+        PCRE  does  not  allow \C to appear in lookbehind assertions (described
-        because in UTF-8 mode it makes it impossible to calculate the length of
+        below), because in UTF-8 mode this would make it impossible  to  calcu-
-        the lookbehind.
+        late the length of the lookbehind.
- SQUARE BRACKETS
+ SQUARE BRACKETS AND CHARACTER CLASSES
         An opening square bracket introduces a character class, terminated by a
         closing square bracket. A closing square bracket on its own is not spe-
         cial. If a closing square bracket is required as a member of the class,
-        it  should  be  the first data character in the class (after an initial
+        it should be the first data character in the class  (after  an  initial
         circumflex, if present) or escaped with a backslash.
-        A character class matches a single character in the subject.  In  UTF-8
+        A  character  class matches a single character in the subject. In UTF-8
-        mode,  the character may occupy more than one byte. A matched character
+        mode, the character may occupy more than one byte. A matched  character
         must be in the set of characters defined by the class, unless the first
-        character  in  the  class definition is a circumflex, in which case the
+        character in the class definition is a circumflex, in  which  case  the
-        subject character must not be in the set defined by  the  class.  If  a
+        subject  character  must  not  be in the set defined by the class. If a
-        circumflex  is actually required as a member of the class, ensure it is
+        circumflex is actually required as a member of the class, ensure it  is
         not the first character, or escape it with a backslash.
-        For example, the character class [aeiou] matches any lower case  vowel,
+        For  example, the character class [aeiou] matches any lower case vowel,
-        while  [^aeiou]  matches  any character that is not a lower case vowel.
+        while [^aeiou] matches any character that is not a  lower  case  vowel.
         Note that a circumflex is just a convenient notation for specifying the
-        characters which are in the class by enumerating those that are not. It
+        characters that are in the class by enumerating those that are  not.  A
-        is not an assertion: it still consumes a  character  from  the  subject
+        class  that starts with a circumflex is not an assertion: it still con-
-        string, and fails if the current pointer is at the end of the string.
+        sumes a character from the subject string, and therefore  it  fails  if
+        the current pointer is at the end of the string.
         In  UTF-8 mode, characters with values greater than 255 can be included
         in a class as a literal string of bytes, or by using the  \x{  escaping
-Line 1949 
 SQUARE BRACKETS
+Line 2293 
 SQUARE BRACKETS
         When  caseless  matching  is set, any letters in a class represent both
         their upper case and lower case versions, so for  example,  a  caseless
         [aeiou]  matches  "A"  as well as "a", and a caseless [^aeiou] does not
-        match "A", whereas a caseful version would. PCRE does not  support  the
+        match "A", whereas a caseful version would. When running in UTF-8 mode,
-        concept of case for characters with values greater than 255.
+        PCRE  supports  the  concept of case for characters with values greater
+        than 128 only when it is compiled with Unicode property support.
-        The  newline character is never treated in any special way in character
+        The newline character is never treated in any special way in  character
-        classes, whatever the setting  of  the  PCRE_DOTALL  or  PCRE_MULTILINE
+        classes,  whatever  the  setting  of  the PCRE_DOTALL or PCRE_MULTILINE
         options is. A class such as [^a] will always match a newline.
-        The  minus (hyphen) character can be used to specify a range of charac-
+        The minus (hyphen) character can be used to specify a range of  charac-
-        ters in a character  class.  For  example,  [d-m]  matches  any  letter
+        ters  in  a  character  class.  For  example,  [d-m] matches any letter
-        between  d  and  m,  inclusive.  If  a minus character is required in a
+        between d and m, inclusive. If a  minus  character  is  required  in  a
-        class, it must be escaped with a backslash  or  appear  in  a  position
+        class,  it  must  be  escaped  with a backslash or appear in a position
-        where  it cannot be interpreted as indicating a range, typically as the
+        where it cannot be interpreted as indicating a range, typically as  the
         first or last character in the class.
         It is not possible to have the literal character "]" as the end charac-
-        ter  of a range. A pattern such as [W-]46] is interpreted as a class of
+        ter of a range. A pattern such as [W-]46] is interpreted as a class  of
-        two characters ("W" and "-") followed by a literal string "46]", so  it
+        two  characters ("W" and "-") followed by a literal string "46]", so it
-        would  match  "W46]"  or  "-46]". However, if the "]" is escaped with a
+        would match "W46]" or "-46]". However, if the "]"  is  escaped  with  a
-        backslash it is interpreted as the end of range, so [W-\]46] is  inter-
+        backslash  it is interpreted as the end of range, so [W-\]46] is inter-
-        preted  as  a  single class containing a range followed by two separate
+        preted as a class containing a range followed by two other  characters.
-        characters. The octal or hexadecimal representation of "]" can also  be
+        The  octal or hexadecimal representation of "]" can also be used to end
-        used to end a range.
+        a range.
-        Ranges  operate in the collating sequence of character values. They can
+        Ranges operate in the collating sequence of character values. They  can
-        also  be  used  for  characters  specified  numerically,  for   example
+        also   be  used  for  characters  specified  numerically,  for  example
-        [\000-\037].  In UTF-8 mode, ranges can include characters whose values
+        [\000-\037]. In UTF-8 mode, ranges can include characters whose  values
         are greater than 255, for example [\x{100}-\x{2ff}].
         If a range that includes letters is used when caseless matching is set,
         it matches the letters in either case. For example, [W-c] is equivalent
-        to [][\^_`wxyzabc], matched caselessly, and if character tables for the
+        to  [][\\^_`wxyzabc],  matched  caselessly,  and  in non-UTF-8 mode, if
-        "fr"  locale  are  in use, [\xc8-\xcb] matches accented E characters in
+        character tables for the "fr_FR" locale are in use, [\xc8-\xcb] matches
-        both cases.
+        accented  E  characters in both cases. In UTF-8 mode, PCRE supports the
+        concept of case for characters with values greater than 128  only  when
-        The character types \d, \D, \s, \S, \w, and \W may  also  appear  in  a
+        it is compiled with Unicode property support.
-        character  class,  and add the characters that they match to the class.
-        For example, [\dABCDEF] matches any hexadecimal digit. A circumflex can
+        The  character types \d, \D, \p, \P, \s, \S, \w, and \W may also appear
-        conveniently  be  used with the upper case character types to specify a
+        in a character class, and add the characters that  they  match  to  the
-        more restricted set of characters than the matching  lower  case  type.
+        class. For example, [\dABCDEF] matches any hexadecimal digit. A circum-
-        For  example,  the  class  [^\W_]  matches any letter or digit, but not
+        flex can conveniently be used with the upper case  character  types  to
-        underscore.
+        specify  a  more  restricted  set of characters than the matching lower
+        case type. For example, the class [^\W_] matches any letter  or  digit,
-        All non-alphameric characters other than \, -, ^ (at the start) and the
+        but not underscore.
-        terminating ] are non-special in character classes, but it does no harm
-        if they are escaped.
+        The  only  metacharacters  that are recognized in character classes are
+        backslash, hyphen (only where it can be  interpreted  as  specifying  a
+        range),  circumflex  (only  at the start), opening square bracket (only
+        when it can be interpreted as introducing a POSIX class name - see  the
+        next  section),  and  the  terminating closing square bracket. However,
+        escaping other non-alphanumeric characters does no harm.
  POSIX CHARACTER CLASSES
-        Perl supports the POSIX notation  for  character  classes,  which  uses
+        Perl supports the POSIX notation for character classes. This uses names
-        names  enclosed by [: and :] within the enclosing square brackets. PCRE
+        enclosed  by  [: and :] within the enclosing square brackets. PCRE also
-        also supports this notation. For example,
+        supports this notation. For example,
           [01[:alpha:]%]
-Line 2037 
 POSIX CHARACTER CLASSES
+Line 2387 
 POSIX CHARACTER CLASSES
         POSIX syntax [.ch.] and [=ch=] where "ch" is a "collating element", but
         these are not supported, and an error is given if they are encountered.
-        In UTF-8 mode, characters with values greater than 255 do not match any
+        In UTF-8 mode, characters with values greater than 128 do not match any
         of the POSIX character classes.
-Line 2104 
 INTERNAL OPTION SETTING
+Line 2454 
 INTERNAL OPTION SETTING
         in the same way as the Perl-compatible options by using the  characters
         U  and X respectively. The (?X) flag setting is special in that it must
         always occur earlier in the pattern than any of the additional features
-        it turns on, even when it is at top level. It is best put at the start.
+        it  turns on, even when it is at top level. It is best to put it at the
+        start.
  SUBPATTERNS
         Subpatterns are delimited by parentheses (round brackets), which can be
-        nested.  Marking part of a pattern as a subpattern does two things:
+        nested.  Turning part of a pattern into a subpattern does two things:
 . It localizes a set of alternatives. For example, the pattern
-Line 2120 
 SUBPATTERNS
+Line 2471 
 SUBPATTERNS
         the parentheses, it would match "cataract",  "erpillar"  or  the  empty
         string.
-.  It  sets  up  the  subpattern as a capturing subpattern (as defined
+.  It  sets  up  the  subpattern as a capturing subpattern. This means
-        above).  When the whole pattern matches, that portion  of  the  subject
+        that, when the whole pattern  matches,  that  portion  of  the  subject
         string that matched the subpattern is passed back to the caller via the
         ovector argument of pcre_exec(). Opening parentheses are  counted  from
-        left  to right (starting from 1) to obtain the numbers of the capturing
+        left  to  right  (starting  from 1) to obtain numbers for the capturing
         subpatterns.
         For example, if the string "the red king" is matched against  the  pat-
-Line 2169 
 NAMED SUBPATTERNS
+Line 2520 
 NAMED SUBPATTERNS
         Identifying  capturing  parentheses  by number is simple, but it can be
         very hard to keep track of the numbers in complicated  regular  expres-
         sions.  Furthermore,  if  an  expression  is  modified, the numbers may
-        change. To help with the difficulty, PCRE supports the naming  of  sub-
+        change. To help with this difficulty, PCRE supports the naming of  sub-
         patterns,  something  that  Perl  does  not  provide. The Python syntax
         (?P<name>...) is used. Names consist  of  alphanumeric  characters  and
         underscores, and must be unique within a pattern.
         Named  capturing  parentheses  are  still  allocated numbers as well as
         names. The PCRE API provides function calls for extracting the name-to-
-        number  translation  table from a compiled pattern. For further details
+        number  translation table from a compiled pattern. There is also a con-
-        see the pcreapi documentation.
+        venience function for extracting a captured substring by name. For fur-
+        ther details see the pcreapi documentation.
  REPETITION
-        Repetition is specified by quantifiers, which can  follow  any  of  the
+        Repetition  is  specified  by  quantifiers, which can follow any of the
         following items:
           a literal data character
           the . metacharacter
           the \C escape sequence
-          escapes such as \d that match single characters
+          the \X escape sequence (in UTF-8 mode with Unicode properties)
+          an escape such as \d that matches a single character
           a character class
           a back reference (see next section)
           a parenthesized subpattern (unless it is an assertion)
-        The  general repetition quantifier specifies a minimum and maximum num-
+        The general repetition quantifier specifies a minimum and maximum  num-
-        ber of permitted matches, by giving the two numbers in  curly  brackets
+        ber  of  permitted matches, by giving the two numbers in curly brackets
-        (braces),  separated  by  a comma. The numbers must be less than 65536,
+        (braces), separated by a comma. The numbers must be  less  than  65536,
         and the first must be less than or equal to the second. For example:
           z{2,4}
-        matches "zz", "zzz", or "zzzz". A closing brace on its  own  is  not  a
+        matches  "zz",  "zzz",  or  "zzzz". A closing brace on its own is not a
-        special  character.  If  the second number is omitted, but the comma is
+        special character. If the second number is omitted, but  the  comma  is
-        present, there is no upper limit; if the second number  and  the  comma
+        present,  there  is  no upper limit; if the second number and the comma
-        are  both omitted, the quantifier specifies an exact number of required
+        are both omitted, the quantifier specifies an exact number of  required
         matches. Thus
           [aeiou]{3,}
-Line 2212 
 REPETITION
+Line 2565 
 REPETITION
           \d{8}
-        matches exactly 8 digits. An opening curly bracket that  appears  in  a
+        matches  exactly  8  digits. An opening curly bracket that appears in a
-        position  where a quantifier is not allowed, or one that does not match
+        position where a quantifier is not allowed, or one that does not  match
-        the syntax of a quantifier, is taken as a literal character. For  exam-
+        the  syntax of a quantifier, is taken as a literal character. For exam-
         ple, {,6} is not a quantifier, but a literal string of four characters.
-        In UTF-8 mode, quantifiers apply to UTF-8  characters  rather  than  to
+        In  UTF-8  mode,  quantifiers  apply to UTF-8 characters rather than to
         individual bytes. Thus, for example, \x{100}{2} matches two UTF-8 char-
-        acters, each of which is represented by a two-byte sequence.
+        acters, each of which is represented by a two-byte sequence. Similarly,
+        when Unicode property support is available, \X{3} matches three Unicode
+        extended  sequences,  each of which may be several bytes long (and they
+        may be of different lengths).
         The quantifier {0} is permitted, causing the expression to behave as if
         the previous item and the quantifier were not present.
-Line 2247 
 REPETITION
+Line 2603 
 REPETITION
         as  possible  (up  to  the  maximum number of permitted times), without
         causing the rest of the pattern to fail. The classic example  of  where
         this gives problems is in trying to match comments in C programs. These
-        appear between the sequences /* and */ and within the  sequence,  indi-
+        appear between /* and */ and within the comment,  individual  *  and  /
-        vidual * and / characters may appear. An attempt to match C comments by
+        characters  may  appear. An attempt to match C comments by applying the
-        applying the pattern
+        pattern
           /\*.*\*/
         to the string
-          /* first command */  not comment  /* second comment */
+          /* first comment */  not comment  /* second comment */
         fails, because it matches the entire string owing to the greediness  of
         the .*  item.
-Line 2283 
 REPETITION
+Line 2639 
 REPETITION
         words, it inverts the default behaviour.
         When  a  parenthesized  subpattern  is quantified with a minimum repeat
-        count that is greater than 1 or with a limited maximum, more  store  is
+        count that is greater than 1 or with a limited maximum, more memory  is
         required  for  the  compiled  pattern, in proportion to the size of the
         minimum or maximum.
-Line 2374 
 ATOMIC GROUPING AND POSSESSIVE QUANTIFIE
+Line 2730 
 ATOMIC GROUPING AND POSSESSIVE QUANTIFIE
         consists  of  an  additional  + character following a quantifier. Using
         this notation, the previous example can be rewritten as
-          \d++bar
+          \d++foo
         Possessive  quantifiers  are  always  greedy;  the   setting   of   the
         PCRE_UNGREEDY option is ignored. They are a convenient notation for the
-Line 2399 
 ATOMIC GROUPING AND POSSESSIVE QUANTIFIE
+Line 2755 
 ATOMIC GROUPING AND POSSESSIVE QUANTIFIE
           aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
         it takes a long time before reporting  failure.  This  is  because  the
-        string  can  be  divided  between  the two repeats in a large number of
+        string  can be divided between the internal \D+ repeat and the external
-        ways, and all have to be tried. (The example used [!?]  rather  than  a
+        * repeat in a large number of ways, and all  have  to  be  tried.  (The
-        single  character  at the end, because both PCRE and Perl have an opti-
+        example  uses  [!?]  rather than a single character at the end, because
-        mization that allows for fast failure when a single character is  used.
+        both PCRE and Perl have an optimization that allows  for  fast  failure
-        They  remember  the last single character that is required for a match,
+        when  a single character is used. They remember the last single charac-
-        and fail early if it is not present in the string.)  If the pattern  is
+        ter that is required for a match, and fail early if it is  not  present
-        changed to
+        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. See the section
+        to the left of the reference for numbers less than 10. See the  subsec-
-        entitled "Backslash" above for further details of the handling of  dig-
+        tion  entitled  "Non-printing  characters" above for further details of
-        its following a backslash.
+        the handling of digits following a backslash.
-        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 Python  syntax  (?P=name).
+        Back  references  to named subpatterns use the Python syntax (?P=name).
         We could rewrite the above example as follows:
           (?<p1>(?i)rah)\s+(?P=p1)
-        There  may be more than one back reference to the same subpattern. If a
+        There may be more than one back reference to the same subpattern. If  a
-        subpattern has not actually been used in a particular match,  any  back
+        subpattern  has  not actually been used in a particular match, any back
         references to it always fail. For example, the pattern
           (a|(bc))\2
-        always  fails if it starts to match "a" rather than "bc". Because there
+        always fails if it starts to match "a" rather than "bc". Because  there
-        may be many capturing parentheses in a pattern,  all  digits  following
+        may  be  many  capturing parentheses in a pattern, all digits following
-        the  backslash  are taken as part of a potential back reference number.
+        the backslash are taken as part of a potential back  reference  number.
         If the pattern continues with a digit character, some delimiter must be
-        used  to  terminate  the back reference. If the PCRE_EXTENDED option is
+        used to terminate the back reference. If the  PCRE_EXTENDED  option  is
-        set, this can be whitespace.  Otherwise an empty comment can be used.
+        set,  this  can  be  whitespace.  Otherwise an empty comment (see "Com-
+        ments" below) can be used.
         A back reference that occurs inside the parentheses to which it  refers
         fails  when  the subpattern is first used, so, for example, (a\1) never
-Line 2482 
 ASSERTIONS
+Line 2840 
 ASSERTIONS
         An assertion is a test on the characters  following  or  preceding  the
         current  matching  point that does not actually consume any characters.
         The simple assertions coded as \b, \B, \A, \G, \Z,  \z,  ^  and  $  are
-        described above.  More complicated assertions are coded as subpatterns.
+        described above.
-        There are two kinds: those that look ahead of the current  position  in
-        the subject string, and those that look behind it.
+        More  complicated  assertions  are  coded as subpatterns. There are two
+        kinds: those that look ahead of the current  position  in  the  subject
-        An  assertion  subpattern  is matched in the normal way, except that it
+        string,  and  those  that  look  behind  it. An assertion subpattern is
-        does not cause the current matching position to be  changed.  Lookahead
+        matched in the normal way, except that it does not  cause  the  current
-        assertions  start with (?= for positive assertions and (?! for negative
+        matching position to be changed.
-        assertions. For example,
+        Assertion  subpatterns  are  not  capturing subpatterns, and may not be
+        repeated, because it makes no sense to assert the  same  thing  several
+        times.  If  any kind of assertion contains capturing subpatterns within
+        it, these are counted for the purposes of numbering the capturing  sub-
+        patterns in the whole pattern.  However, substring capturing is carried
+        out only for positive assertions, because it does not  make  sense  for
+        negative assertions.
+    Lookahead assertions
+        Lookahead assertions start with (?= for positive assertions and (?! for
+        negative assertions. For example,
           \w+(?=;)
-Line 2506 
 ASSERTIONS
+Line 2876 
 ASSERTIONS
         does not find an occurrence of "bar"  that  is  preceded  by  something
         other  than "foo"; it finds any occurrence of "bar" whatsoever, because
         the assertion (?!foo) is always true when the next three characters are
-        "bar". A lookbehind assertion is needed to achieve this effect.
+        "bar". A lookbehind assertion is needed to achieve the other effect.
         If you want to force a matching failure at some point in a pattern, the
         most convenient way to do it is  with  (?!)  because  an  empty  string
         always  matches, so an assertion that requires there not to be an empty
         string must always fail.
+    Lookbehind assertions
         Lookbehind assertions start with (?<= for positive assertions and  (?<!
         for negative assertions. For example,
-Line 2551 
 ASSERTIONS
+Line 2923 
 ASSERTIONS
         PCRE does not allow the \C escape (which matches a single byte in UTF-8
         mode)  to appear in lookbehind assertions, because it makes it impossi-
-        ble to calculate the length of the lookbehind.
+        ble to calculate the length of the lookbehind. The \X escape, which can
+        match different numbers of bytes, is also not permitted.
-        Atomic groups can be used in conjunction with lookbehind assertions  to
+        Atomic  groups can be used in conjunction with lookbehind assertions to
         specify efficient matching at the end of the subject string. Consider a
         simple pattern such as
           abcd$
-        when applied to a long string that does  not  match.  Because  matching
+        when  applied  to  a  long string that does not match. Because matching
         proceeds from left to right, PCRE will look for each "a" in the subject
-        and then see if what follows matches the rest of the  pattern.  If  the
+        and  then  see  if what follows matches the rest of the pattern. If the
         pattern is specified as
           ^.*abcd$
-        the  initial .* matches the entire string at first, but when this fails
+        the initial .* matches the entire string at first, but when this  fails
         (because there is no following "a"), it backtracks to match all but the
-        last  character,  then all but the last two characters, and so on. Once
+        last character, then all but the last two characters, and so  on.  Once
-        again the search for "a" covers the entire string, from right to  left,
+        again  the search for "a" covers the entire string, from right to left,
         so we are no better off. However, if the pattern is written as
           ^(?>.*)(?<=abcd)
-        or, equivalently,
+        or, equivalently, using the possessive quantifier syntax,
           ^.*+(?<=abcd)
-        there  can  be  no  backtracking for the .* item; it can match only the
+        there can be no backtracking for the .* item; it  can  match  only  the
-        entire string. The subsequent lookbehind assertion does a  single  test
+        entire  string.  The subsequent lookbehind assertion does a single test
-        on  the last four characters. If it fails, the match fails immediately.
+        on the last four characters. If it fails, the match fails  immediately.
-        For long strings, this approach makes a significant difference  to  the
+        For  long  strings, this approach makes a significant difference to the
         processing time.
+    Using multiple assertions
         Several assertions (of any sort) may occur in succession. For example,
           (?<=\d{3})(?<!999)foo
-        matches  "foo" preceded by three digits that are not "999". Notice that
+        matches "foo" preceded by three digits that are not "999". Notice  that
-        each of the assertions is applied independently at the  same  point  in
+        each  of  the  assertions is applied independently at the same point in
-        the  subject  string.  First  there  is a check that the previous three
+        the subject string. First there is a  check  that  the  previous  three
-        characters are all digits, and then there is  a  check  that  the  same
+        characters  are  all  digits,  and  then there is a check that the same
         three characters are not "999".  This pattern does not match "foo" pre-
-        ceded by six characters, the first of which are  digits  and  the  last
+        ceded  by  six  characters,  the first of which are digits and the last
-        three  of  which  are not "999". For example, it doesn't match "123abc-
+        three of which are not "999". For example, it  doesn't  match  "123abc-
         foo". A pattern to do that is
           (?<=\d{3}...)(?<!999)foo
-        This time the first assertion looks at the  preceding  six  characters,
+        This  time  the  first assertion looks at the preceding six characters,
         checking that the first three are digits, and then the second assertion
         checks that the preceding three characters are not "999".
-Line 2607 
 ASSERTIONS
+Line 2982 
 ASSERTIONS
           (?<=(?<!foo)bar)baz
-        matches an occurrence of "baz" that is preceded by "bar" which in  turn
+        matches  an occurrence of "baz" that is preceded by "bar" which in turn
         is not preceded by "foo", while
           (?<=\d{3}(?!999)...)foo
-        is another pattern which matches "foo" preceded by three digits and any
+        is another pattern that matches "foo" preceded by three digits and  any
         three characters that are not "999".
-        Assertion subpatterns are not capturing subpatterns,  and  may  not  be
-        repeated,  because  it  makes no sense to assert the same thing several
-        times. If any kind of assertion contains capturing  subpatterns  within
-        it,  these are counted for the purposes of numbering the capturing sub-
-        patterns in the whole pattern.  However, substring capturing is carried
-        out  only  for  positive assertions, because it does not make sense for
-        negative assertions.
  CONDITIONAL SUBPATTERNS
-        It is possible to cause the matching process to obey a subpattern  con-
+        It  is possible to cause the matching process to obey a subpattern con-
-        ditionally  or to choose between two alternative subpatterns, depending
+        ditionally or to choose between two alternative subpatterns,  depending
-        on the  result  of  an  assertion,  or  whether  a  previous  capturing
+        on  the result of an assertion, or whether a previous capturing subpat-
-        subpattern  matched  or not. The two possible forms of conditional sub-
+        tern matched or not. The two possible forms of  conditional  subpattern
-        pattern are
+        are
           (?(condition)yes-pattern)
           (?(condition)yes-pattern|no-pattern)
-        If the condition is satisfied, the yes-pattern is used;  otherwise  the
+        If  the  condition is satisfied, the yes-pattern is used; otherwise the
-        no-pattern  (if  present)  is used. If there are more than two alterna-
+        no-pattern (if present) is used. If there are more  than  two  alterna-
         tives in the subpattern, a compile-time error occurs.
         There are three kinds of condition. If the text between the parentheses
-        consists  of  a  sequence  of digits, the condition is satisfied if the
+        consists of a sequence of digits, the condition  is  satisfied  if  the
-        capturing subpattern of that number has previously matched. The  number
+        capturing  subpattern of that number has previously matched. The number
-        must  be  greater than zero. Consider the following pattern, which con-
+        must be greater than zero. Consider the following pattern,  which  con-
-        tains non-significant white space to make it more readable (assume  the
+        tains  non-significant white space to make it more readable (assume the
-        PCRE_EXTENDED  option)  and  to  divide it into three parts for ease of
+        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 the condition is the string (R), it is satisfied if a recursive call
-        to the pattern or subpattern has been made. At "top level", the  condi-
+        to  the pattern or subpattern has been made. At "top level", the condi-
-        tion  is  false.   This  is  a  PCRE  extension. Recursive patterns are
+        tion is false.  This  is  a  PCRE  extension.  Recursive  patterns  are
         described in the next section.
-        If the condition is not a sequence of digits or  (R),  it  must  be  an
+        If  the  condition  is  not  a sequence of digits or (R), 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 which 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 up to the next new-
         line character 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
-        depth. Perl has provided an experimental facility that  allows  regular
+        depth.  Perl  provides  a  facility  that allows regular expressions to
-        expressions to recurse (amongst other things). It does this by interpo-
+        recurse (amongst other things). It does this by interpolating Perl code
-        lating Perl code in the expression at run time, and the code can  refer
+        in the expression at run time, and the code can refer to the expression
-        to the expression itself. A Perl pattern to solve the parentheses prob-
+        itself. A Perl pattern to solve the parentheses problem can be  created
-        lem can be created like this:
+        like this:
           $re = qr{\( (?: (?>[^()]+) | (?p{$re}) )* \)}x;
         The (?p{...}) item interpolates Perl code at run time, and in this case
-        refers  recursively to the pattern in which it appears. Obviously, PCRE
+        refers recursively to the pattern in which it appears. Obviously,  PCRE
-        cannot support the interpolation of Perl  code.  Instead,  it  supports
+        cannot  support  the  interpolation  of Perl code. Instead, it supports
-        some  special  syntax for recursion of the entire pattern, and also for
+        some special syntax for recursion of the entire pattern, and  also  for
         individual subpattern recursion.
-        The special item that consists of (? followed by a number greater  than
+        The  special item that consists of (? followed by a number greater than
         zero and a closing parenthesis is a recursive call of the subpattern of
-        the given number, provided that it occurs inside that  subpattern.  (If
+        the  given  number, provided that it occurs inside that subpattern. (If
-        not,  it  is  a  "subroutine" call, which is described in the next sec-
+        not, it is a "subroutine" call, which is described  in  the  next  sec-
-        tion.) The special item (?R) is a recursive call of the entire  regular
+        tion.)  The special item (?R) is a recursive call of the entire regular
         expression.
-        For  example,  this  PCRE pattern solves the nested parentheses problem
+        For example, this PCRE pattern solves the  nested  parentheses  problem
-        (assume the  PCRE_EXTENDED  option  is  set  so  that  white  space  is
+        (assume  the  PCRE_EXTENDED  option  is  set  so  that  white  space is
         ignored):
           \( ( (?>[^()]+) | (?R) )* \)
-        First  it matches an opening parenthesis. Then it matches any number of
+        First it matches an opening parenthesis. Then it matches any number  of
-        substrings which can either be a  sequence  of  non-parentheses,  or  a
+        substrings  which  can  either  be  a sequence of non-parentheses, or a
-        recursive  match  of  the pattern itself (that is a correctly parenthe-
+        recursive match of the pattern itself (that is  a  correctly  parenthe-
         sized substring).  Finally there is a closing parenthesis.
-        If this were part of a larger pattern, you would not  want  to  recurse
+        If  this  were  part of a larger pattern, you would not want to recurse
         the entire pattern, so instead you could use this:
           ( \( ( (?>[^()]+) | (?1) )* \) )
-        We  have  put the pattern into parentheses, and caused the recursion to
+        We have put the pattern into parentheses, and caused the  recursion  to
-        refer to them instead of the whole pattern. In a larger pattern,  keep-
+        refer  to them instead of the whole pattern. In a larger pattern, keep-
-        ing  track  of parenthesis numbers can be tricky. It may be more conve-
+        ing track of parenthesis numbers can be tricky. It may be  more  conve-
-        nient to use named parentheses instead. For this, PCRE uses  (?P>name),
+        nient  to use named parentheses instead. For this, PCRE uses (?P>name),
-        which  is  an  extension  to the Python syntax that PCRE uses for named
+        which is an extension to the Python syntax that  PCRE  uses  for  named
         parentheses (Perl does not provide named parentheses). We could rewrite
         the above example as follows:
           (?P<pn> \( ( (?>[^()]+) | (?P>pn) )* \) )
-        This  particular example pattern contains nested unlimited repeats, and
+        This particular example pattern contains nested unlimited repeats,  and
-        so the use of atomic grouping for matching strings  of  non-parentheses
+        so  the  use of atomic grouping for matching strings of non-parentheses
-        is  important  when  applying the pattern to strings that do not match.
+        is important when applying the pattern to strings that  do  not  match.
         For example, when this pattern is applied to
           (aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa()
-        it yields "no match" quickly. However, if atomic grouping is not  used,
+        it  yields "no match" quickly. However, if atomic grouping is not used,
-        the  match  runs  for a very long time indeed because there are so many
+        the match runs for a very long time indeed because there  are  so  many
-        different ways the + and * repeats can carve up the  subject,  and  all
+        different  ways  the  + and * repeats can carve up the subject, and all
         have to be tested before failure can be reported.
         At the end of a match, the values set for any capturing subpatterns are
         those from the outermost level of the recursion at which the subpattern
-        value  is  set.   If  you want to obtain intermediate values, a callout
+        value is set.  If you want to obtain  intermediate  values,  a  callout
-        function can be used (see below and the pcrecallout documentation).  If
+        function can be used (see the next section and the pcrecallout documen-
-        the pattern above is matched against
+        tation). If the pattern above is matched against
           (ab(cd)ef)
-        the  value  for  the  capturing  parentheses is "ef", which is the last
+        the value for the capturing parentheses is  "ef",  which  is  the  last
-        value taken on at the top level. If additional parentheses  are  added,
+        value  taken  on at the top level. If additional parentheses are added,
         giving
           \( ( ( (?>[^()]+) | (?R) )* ) \)
              ^                        ^
              ^                        ^
-        the  string  they  capture is "ab(cd)ef", the contents of the top level
+        the string they capture is "ab(cd)ef", the contents of  the  top  level
-        parentheses. If there are more than 15 capturing parentheses in a  pat-
+        parentheses.  If there are more than 15 capturing parentheses in a pat-
         tern, PCRE has to obtain extra memory to store data during a recursion,
-        which it does by using pcre_malloc, freeing  it  via  pcre_free  after-
+        which  it  does  by  using pcre_malloc, freeing it via pcre_free after-
-        wards.  If  no  memory  can  be  obtained,  the  match  fails  with the
+        wards. If  no  memory  can  be  obtained,  the  match  fails  with  the
         PCRE_ERROR_NOMEMORY error.
-        Do not confuse the (?R) item with the condition (R),  which  tests  for
+        Do  not  confuse  the (?R) item with the condition (R), which tests for
-        recursion.   Consider  this pattern, which matches text in angle brack-
+        recursion.  Consider this pattern, which matches text in  angle  brack-
-        ets, allowing for arbitrary nesting. Only digits are allowed in  nested
+        ets,  allowing for arbitrary nesting. Only digits are allowed in nested
-        brackets  (that is, when recursing), whereas any characters are permit-
+        brackets (that is, when recursing), whereas any characters are  permit-
         ted at the outer level.
           < (?: (?(R) \d++  | [^<>]*+) | (?R)) * >
-        In this pattern, (?(R) is the start of a conditional  subpattern,  with
+        In  this  pattern, (?(R) is the start of a conditional subpattern, with
-        two  different  alternatives for the recursive and non-recursive cases.
+        two different alternatives for the recursive and  non-recursive  cases.
         The (?R) item is the actual recursive call.
  SUBPATTERNS AS SUBROUTINES
         If the syntax for a recursive subpattern reference (either by number or
-        by  name)  is used outside the parentheses to which it refers, it oper-
+        by name) is used outside the parentheses to which it refers,  it  oper-
-        ates like a subroutine in a programming language.  An  earlier  example
+        ates  like  a  subroutine in a programming language. An earlier example
         pointed out that 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 instead the pattern
           (sens|respons)e and (?1)ibility
-        is used, it does match "sense and responsibility" as well as the  other
+        is  used, it does match "sense and responsibility" as well as the other
-        two  strings.  Such  references must, however, follow the subpattern to
+        two strings. Such references must, however, follow  the  subpattern  to
         which they refer.
  CALLOUTS
         Perl has a feature whereby using the sequence (?{...}) causes arbitrary
-        Perl  code to be obeyed in the middle of matching a regular expression.
+        Perl code to be obeyed in the middle of matching a regular  expression.
         This makes it possible, amongst other things, to extract different sub-
         strings that match the same pair of parentheses when there is a repeti-
         tion.
         PCRE provides a similar feature, but of course it cannot obey arbitrary
         Perl code. The feature is called "callout". The caller of PCRE provides
-        an external function by putting its entry point in the global  variable
+        an  external function by putting its entry point in the global variable
-        pcre_callout.   By default, this variable contains NULL, which disables
+        pcre_callout.  By default, this variable contains NULL, which  disables
         all calling out.
-        Within a regular expression, (?C) indicates the  points  at  which  the
+        Within  a  regular  expression,  (?C) indicates the points at which the
-        external  function  is  to be called. If you want to identify different
+        external function is to be called. If you want  to  identify  different
-        callout points, you can put a number less than 256 after the letter  C.
+        callout  points, you can put a number less than 256 after the letter C.
-        The  default  value is zero.  For example, this pattern has two callout
+        The default value is zero.  For example, this pattern has  two  callout
         points:
           (?C1)abc(?C2)def
+        If the PCRE_AUTO_CALLOUT flag is passed to pcre_compile(), callouts are
+        automatically installed before each item in the pattern. They  are  all
+        numbered 255.
         During matching, when PCRE reaches a callout point (and pcre_callout is
-        set),  the  external function is called. It is provided with the number
+        set), the external function is called. It is provided with  the  number
-        of the callout, and, optionally, one item of data  originally  supplied
+        of  the callout, the position in the pattern, and, optionally, one item
-        by  the  caller of pcre_exec(). The callout function may cause matching
+        of data originally supplied by the caller of pcre_exec().  The  callout
-        to backtrack, or to fail altogether.  A  complete  description  of  the
+        function  may cause matching to proceed, to backtrack, or to fail alto-
-        interface  to the callout function is given in the pcrecallout documen-
+        gether. A complete description of the interface to the callout function
-        tation.
+        is given in the pcrecallout documentation.
- Last updated: 03 February 2003
+ Last updated: 09 September 2004
- Copyright (c) 1997-2003 University of Cambridge.
+ Copyright (c) 1997-2004 University of Cambridge.
+ -----------------------------------------------------------------------------
+ PCRE(3)                                                                PCRE(3)
+ NAME
+        PCRE - Perl-compatible regular expressions
+ PARTIAL MATCHING IN PCRE
+        In  normal  use  of  PCRE,  if  the  subject  string  that is passed to
+        pcre_exec() matches as far as it goes, but is too short  to  match  the
+        entire pattern, PCRE_ERROR_NOMATCH is returned. There are circumstances
+        where it might be helpful to distinguish this case from other cases  in
+        which there is no match.
+        Consider, for example, an application where a human is required to type
+        in data for a field with specific formatting requirements.  An  example
+        might be a date in the form ddmmmyy, defined by this pattern:
+          ^\d?\d(jan|feb|mar|apr|may|jun|jul|aug|sep|oct|nov|dec)\d\d$
+        If the application sees the user's keystrokes one by one, and can check
+        that what has been typed so far is potentially valid,  it  is  able  to
+        raise  an  error as soon as a mistake is made, possibly beeping and not
+        reflecting the character that has been typed. This  immediate  feedback
+        is  likely  to  be a better user interface than a check that is delayed
+        until the entire string has been entered.
+        PCRE supports the concept of partial matching by means of the PCRE_PAR-
+        TIAL  option,  which  can be set when calling pcre_exec(). When this is
+        done,  the   return   code   PCRE_ERROR_NOMATCH   is   converted   into
+        PCRE_ERROR_PARTIAL  if  at  any  time  during  the matching process the
+        entire subject string matched part of the pattern. No captured data  is
+        set when this occurs.
+        Using PCRE_PARTIAL disables one of PCRE's optimizations. PCRE remembers
+        the last literal byte in a pattern, and abandons  matching  immediately
+        if  such a byte is not present in the subject string. This optimization
+        cannot be used for a subject string that might match only partially.
+ RESTRICTED PATTERNS FOR PCRE_PARTIAL
+        Because of the way certain internal optimizations  are  implemented  in
+        PCRE,  the  PCRE_PARTIAL  option  cannot  be  used  with  all patterns.
+        Repeated single characters such as
+          a{2,4}
+        and repeated single metasequences such as
+          \d+
+        are not permitted if the maximum number of occurrences is greater  than
+        one.  Optional items such as \d? (where the maximum is one) are permit-
+        ted.  Quantifiers with any values are permitted after  parentheses,  so
+        the invalid examples above can be coded thus:
+          (a){2,4}
+          (\d)+
+        These  constructions  run more slowly, but for the kinds of application
+        that are envisaged for this facility, this is not felt to  be  a  major
+        restriction.
+        If  PCRE_PARTIAL  is  set  for  a  pattern that does not conform to the
+        restrictions, pcre_exec() returns the error code  PCRE_ERROR_BADPARTIAL
+        (-13).
+ EXAMPLE OF PARTIAL MATCHING USING PCRETEST
+        If  the  escape  sequence  \P  is  present in a pcretest data line, the
+        PCRE_PARTIAL flag is used for the match. Here is a run of pcretest that
+        uses the date example quoted above:
+            re> /^\d?\d(jan|feb|mar|apr|may|jun|jul|aug|sep|oct|nov|dec)\d\d$/
+          data> 25jun04P
+: 25jun04
+: jun
+          data> 25dec3P
+          Partial match
+          data> 3juP
+          Partial match
+          data> 3jujP
+          No match
+          data> jP
+          No match
+        The  first  data  string  is  matched completely, so pcretest shows the
+        matched substrings. The remaining four strings do not  match  the  com-
+        plete pattern, but the first two are partial matches.
+ Last updated: 08 September 2004
+ Copyright (c) 1997-2004 University of Cambridge.
+ -----------------------------------------------------------------------------
+ PCRE(3)                                                                PCRE(3)
+ NAME
+        PCRE - Perl-compatible regular expressions
+ SAVING AND RE-USING PRECOMPILED PCRE PATTERNS
+        If  you  are running an application that uses a large number of regular
+        expression patterns, it may be useful to store them  in  a  precompiled
+        form  instead  of  having to compile them every time the application is
+        run.  If you are not  using  any  private  character  tables  (see  the
+        pcre_maketables()  documentation),  this is relatively straightforward.
+        If you are using private tables, it is a little bit more complicated.
+        If you save compiled patterns to a file, you can copy them to a differ-
+        ent  host  and  run them there. This works even if the new host has the
+        opposite endianness to the one on which  the  patterns  were  compiled.
+        There  may  be a small performance penalty, but it should be insignifi-
+        cant.
+ SAVING A COMPILED PATTERN
+        The value returned by pcre_compile() points to a single block of memory
+        that  holds  the compiled pattern and associated data. You can find the
+        length of this block in bytes by calling pcre_fullinfo() with an  argu-
+        ment  of  PCRE_INFO_SIZE. You can then save the data in any appropriate
+        manner. Here is sample code that compiles a pattern and writes it to  a
+        file. It assumes that the variable fd refers to a file that is open for
+        output:
+          int erroroffset, rc, size;
+          char *error;
+          pcre *re;
+          re = pcre_compile("my pattern", 0, &error, &erroroffset, NULL);
+          if (re == NULL) { ... handle errors ... }
+          rc = pcre_fullinfo(re, NULL, PCRE_INFO_SIZE, &size);
+          if (rc < 0) { ... handle errors ... }
+          rc = fwrite(re, 1, size, fd);
+          if (rc != size) { ... handle errors ... }
+        In this example, the bytes  that  comprise  the  compiled  pattern  are
+        copied  exactly.  Note that this is binary data that may contain any of
+        the 256 possible byte  values.  On  systems  that  make  a  distinction
+        between binary and non-binary data, be sure that the file is opened for
+        binary output.
+        If you want to write more than one pattern to a file, you will have  to
+        devise  a  way of separating them. For binary data, preceding each pat-
+        tern with its length is probably  the  most  straightforward  approach.
+        Another  possibility is to write out the data in hexadecimal instead of
+        binary, one pattern to a line.
+        Saving compiled patterns in a file is only one possible way of  storing
+        them  for later use. They could equally well be saved in a database, or
+        in the memory of some daemon process that passes them  via  sockets  to
+        the processes that want them.
+        If  the pattern has been studied, it is also possible to save the study
+        data in a similar way to the compiled  pattern  itself.  When  studying
+        generates  additional  information, pcre_study() returns a pointer to a
+        pcre_extra data block. Its format is defined in the section on matching
+        a  pattern in the pcreapi documentation. The study_data field points to
+        the binary study data,  and  this  is  what  you  must  save  (not  the
+        pcre_extra  block itself). The length of the study data can be obtained
+        by calling pcre_fullinfo() with  an  argument  of  PCRE_INFO_STUDYSIZE.
+        Remember  to check that pcre_study() did return a non-NULL value before
+        trying to save the study data.
+ RE-USING A PRECOMPILED PATTERN
+        Re-using a precompiled pattern is straightforward. Having  reloaded  it
+        into main memory, you pass its pointer to pcre_exec() in the usual way.
+        This should work even on another host, and even if that  host  has  the
+        opposite endianness to the one where the pattern was compiled.
+        However,  if  you  passed a pointer to custom character tables when the
+        pattern was compiled (the tableptr  argument  of  pcre_compile()),  you
+        must now pass a similar pointer to pcre_exec(), because the value saved
+        with the compiled pattern will obviously be  nonsense.  A  field  in  a
+        pcre_extra()  block is used to pass this data, as described in the sec-
+        tion on matching a pattern in the pcreapi documentation.
+        If you did not provide custom character tables  when  the  pattern  was
+        compiled,  the  pointer  in  the compiled pattern is NULL, which causes
+        pcre_exec() to use PCRE's internal tables. Thus, you  do  not  need  to
+        take any special action at run time in this case.
+        If  you  saved study data with the compiled pattern, you need to create
+        your own pcre_extra data block and set the study_data field to point to
+        the  reloaded  study  data. You must also set the PCRE_EXTRA_STUDY_DATA
+        bit in the flags field to indicate that study  data  is  present.  Then
+        pass the pcre_extra block to pcre_exec() in the usual way.
+ COMPATIBILITY WITH DIFFERENT PCRE RELEASES
+        The  layout  of the control block that is at the start of the data that
+        makes up a compiled pattern was changed for release 5.0.  If  you  have
+        any  saved  patterns  that  were compiled with previous releases (not a
+        facility that was previously advertised), you will  have  to  recompile
+        them  for  release  5.0. However, from now on, it should be possible to
+        make changes in a compabible manner.
+ Last updated: 10 September 2004
+ Copyright (c) 1997-2004 University of Cambridge.
  -----------------------------------------------------------------------------
  PCRE(3)                                                                PCRE(3)
-Line 2862 
 PCRE PERFORMANCE
+Line 3441 
 PCRE PERFORMANCE
         like  [aeiou]  than  a set of alternatives such as (a|e|i|o|u). In gen-
         eral, the simplest construction that provides the required behaviour is
         usually  the  most  efficient.  Jeffrey Friedl's book contains a lot of
-        discussion about optimizing regular expressions for  efficient  perfor-
+        useful general discussion  about  optimizing  regular  expressions  for
-        mance.
+        efficient  performance. This document contains a few observations about
+        PCRE.
+        Using Unicode character properties (the \p,  \P,  and  \X  escapes)  is
+        slow,  because PCRE has to scan a structure that contains data for over
+        fifteen thousand characters whenever it needs a  character's  property.
+        If  you  can  find  an  alternative pattern that does not use character
+        properties, it will probably be faster.
-        When  a  pattern  begins  with .* not in parentheses, or in parentheses
+        When a pattern begins with .* not in  parentheses,  or  in  parentheses
         that are not the subject of a backreference, and the PCRE_DOTALL option
-        is  set, the pattern is implicitly anchored by PCRE, since it can match
+        is set, the pattern is implicitly anchored by PCRE, since it can  match
-        only at the start of a subject string. However, if PCRE_DOTALL  is  not
+        only  at  the start of a subject string. However, if PCRE_DOTALL is not
-        set,  PCRE  cannot  make this optimization, because the . metacharacter
+        set, PCRE cannot make this optimization, because  the  .  metacharacter
-        does not then match a newline, and if the subject string contains  new-
+        does  not then match a newline, and if the subject string contains new-
-        lines,  the  pattern may match from the character immediately following
+        lines, the pattern may match from the character  immediately  following
         one of them instead of from the very start. For example, the pattern
           .*second
-        matches the subject "first\nand second" (where \n stands for a  newline
+        matches  the subject "first\nand second" (where \n stands for a newline
-        character),  with the match starting at the seventh character. In order
+        character), with the match starting at the seventh character. In  order
         to do this, PCRE has to retry the match starting after every newline in
         the subject.
-        If  you  are using such a pattern with subject strings that do not con-
+        If you are using such a pattern with subject strings that do  not  con-
         tain newlines, the best performance is obtained by setting PCRE_DOTALL,
-        or  starting  the pattern with ^.* to indicate explicit anchoring. That
+        or starting the pattern with ^.* to indicate explicit  anchoring.  That
-        saves PCRE from having to scan along the subject looking for a  newline
+        saves  PCRE from having to scan along the subject looking for a newline
         to restart at.
-        Beware  of  patterns  that contain nested indefinite repeats. These can
+        Beware of patterns that contain nested indefinite  repeats.  These  can
-        take a long time to run when applied to a string that does  not  match.
+        take  a  long time to run when applied to a string that does not match.
         Consider the pattern fragment
           (a+)*
-        This  can  match "aaaa" in 33 different ways, and this number increases
+        This can match "aaaa" in 33 different ways, and this  number  increases
-        very rapidly as the string gets longer. (The * repeat can match  0,  1,
+        very  rapidly  as the string gets longer. (The * repeat can match 0, 1,
-,  3,  or  4  times,  and  for each of those cases other than 0, the +
+, 3, or 4 times, and for each of those  cases  other  than  0,  the  +
-        repeats can match different numbers of times.) When  the  remainder  of
+        repeats  can  match  different numbers of times.) When the remainder of
         the pattern is such that the entire match is going to fail, PCRE has in
-        principle to try  every  possible  variation,  and  this  can  take  an
+        principle  to  try  every  possible  variation,  and  this  can take an
         extremely long time.
         An optimization catches some of the more simple cases such as
           (a+)*b
-        where  a  literal  character  follows. Before embarking on the standard
+        where a literal character follows. Before  embarking  on  the  standard
-        matching procedure, PCRE checks that there is a "b" later in  the  sub-
+        matching  procedure,  PCRE  checks  that  there  is  a "b" later in the
-        ject  string, and if there is not, it fails the match immediately. How-
+        subject string, and if there is not, it fails  the  match  immediately.
-        ever, when there is no following literal this  optimization  cannot  be
+        However, when there is no following literal this optimization cannot be
         used. You can see the difference by comparing the behaviour of
           (a+)*\d
-        with  the  pattern  above.  The former gives a failure almost instantly
+        with the pattern above. The former gives  a  failure  almost  instantly
-        when applied to a whole line of  "a"  characters,  whereas  the  latter
+        when  applied  to  a  whole  line of "a" characters, whereas the latter
         takes an appreciable time with strings longer than about 20 characters.
- Last updated: 03 February 2003
+        In many cases, the solution to this kind of performance issue is to use
- Copyright (c) 1997-2003 University of Cambridge.
+        an atomic group or a possessive quantifier.
+ Last updated: 09 September 2004
+ Copyright (c) 1997-2004 University of Cambridge.
  -----------------------------------------------------------------------------
  PCRE(3)                                                                PCRE(3)
-Line 2929 
 NAME
+Line 3518 
 NAME
         PCRE - Perl-compatible regular expressions.
  SYNOPSIS OF POSIX API
         #include <pcreposix.h>
         int regcomp(regex_t *preg, const char *pattern,
-Line 2947 
 DESCRIPTION
+Line 3537 
 DESCRIPTION
         This  set  of  functions provides a POSIX-style API to the PCRE regular
         expression package. See the pcreapi documentation for a description  of
-        the native API, which contains additional functionality.
+        PCRE's native API, which contains additional functionality.
         The functions described here are just wrapper functions that ultimately
         call  the  PCRE  native  API.  Their  prototypes  are  defined  in  the
         pcreposix.h  header  file,  and  on  Unix systems the library itself is
         called pcreposix.a, so can be accessed by  adding  -lpcreposix  to  the
-        command  for  linking an application which uses them. Because the POSIX
+        command  for  linking  an application that uses them. Because the POSIX
         functions call the native ones, it is also necessary to add -lpcre.
         I have implemented only those option bits that can be reasonably mapped
-Line 2985 
 COMPILING A PATTERN
+Line 3575 
 COMPILING A PATTERN
         The  function regcomp() is called to compile a pattern into an internal
         form. The pattern is a C string terminated by a  binary  zero,  and  is
         passed  in  the  argument  pattern. The preg argument is a pointer to a
-        regex_t structure which is used as a base for storing information about
+        regex_t structure that is used as a base for storing information  about
         the compiled expression.
         The argument cflags is either zero, or contains one or more of the bits
-Line 3036 
 MATCHING NEWLINE CHARACTERS
+Line 3626 
 MATCHING NEWLINE CHARACTERS
                                   Default   Change with
-          . matches newline          yes      REG_NEWLINE
+          . matches newline          yes    REG_NEWLINE
-          newline matches [^a]       yes      REG_NEWLINE
+          newline matches [^a]       yes    REG_NEWLINE
-          $ matches \n at end        no       REG_NEWLINE
+          $ matches \n at end        no     REG_NEWLINE
-          $ matches \n in middle     no       REG_NEWLINE
+          $ matches \n in middle     no     REG_NEWLINE
-          ^ matches \n in middle     no       REG_NEWLINE
+          ^ matches \n in middle     no     REG_NEWLINE
         PCRE's behaviour is the same as Perl's, except that there is no equiva-
-        lent for PCRE_DOLLARENDONLY in Perl. In both PCRE and Perl, there is no
+        lent for PCRE_DOLLAR_ENDONLY in Perl. In both PCRE and Perl,  there  is
-        way to stop newline from matching [^a].
+        no way to stop newline from matching [^a].
         The   default  POSIX  newline  handling  can  be  obtained  by  setting
-        PCRE_DOTALL and PCRE_DOLLARENDONLY, but there is no way  to  make  PCRE
+        PCRE_DOTALL and PCRE_DOLLAR_ENDONLY, but there is no way to  make  PCRE
         behave exactly as for the REG_NEWLINE action.
  MATCHING A PATTERN
-        The  function  regexec() is called to match a pre-compiled pattern preg
+        The  function  regexec()  is  called  to  match a compiled pattern preg
         against a given string, which is terminated by a zero byte, subject  to
         the options in eflags. These can be:
-Line 3092 
 ERROR MESSAGES
+Line 3682 
 ERROR MESSAGES
         tion is the size of buffer needed to hold the whole message.
- STORAGE
+ MEMORY USAGE
         Compiling a regular expression causes memory to be allocated and  asso-
         ciated  with  the preg structure. The function regfree() frees all such
-Line 3106 
 AUTHOR
+Line 3696 
 AUTHOR
         University Computing Service,
         Cambridge CB2 3QG, England.
- Last updated: 03 February 2003
+ Last updated: 07 September 2004
- Copyright (c) 1997-2003 University of Cambridge.
+ Copyright (c) 1997-2004 University of Cambridge.
  -----------------------------------------------------------------------------
  PCRE(3)                                                                PCRE(3)
-Line 3134 
 PCRE SAMPLE PROGRAM
+Line 3724 
 PCRE SAMPLE PROGRAM
         bility  of  matching an empty string. Comments in the code explain what
         is going on.
-        On a Unix system that has PCRE installed in /usr/local, you can compile
+        If PCRE is installed in the standard include  and  library  directories
-        the demonstration program using a command like this:
+        for  your  system, you should be able to compile the demonstration pro-
+        gram using this command:
+          gcc -o pcredemo pcredemo.c -lpcre
+        If PCRE is installed elsewhere, you may need to add additional  options
+        to  the  command line. For example, on a Unix-like system that has PCRE
+        installed in /usr/local, you  can  compile  the  demonstration  program
+        using a command like this:
-          gcc -o pcredemo pcredemo.c -I/usr/local/include \
+          gcc -o pcredemo -I/usr/local/include pcredemo.c \
               -L/usr/local/lib -lpcre
-        Then you can run simple tests like this:
+        Once  you  have  compiled the demonstration program, you can run simple
+        tests like this:
           ./pcredemo 'cat|dog' 'the cat sat on the mat'
           ./pcredemo -g 'cat|dog' 'the dog sat on the cat'
-        Note  that  there  is  a  much  more comprehensive test program, called
+        Note that there is a  much  more  comprehensive  test  program,  called
-        pcretest, which supports  many  more  facilities  for  testing  regular
+        pcretest,  which  supports  many  more  facilities  for testing regular
         expressions and the PCRE library. The pcredemo program is provided as a
         simple coding example.
-        On some operating systems (e.g. Solaris) you may get an error like this
+        On some operating systems (e.g. Solaris), when PCRE is not installed in
-        when you try to run pcredemo:
+        the standard library directory, you may get an error like this when you
+        try to run pcredemo:
           ld.so.1:  a.out:  fatal:  libpcre.so.0:  open failed: No such file or
         directory
-Line 3161 
 PCRE SAMPLE PROGRAM
+Line 3761 
 PCRE SAMPLE PROGRAM
           -R/usr/local/lib
-        to the compile command to get round this problem.
+        (for example) to the compile command to get round this problem.
- Last updated: 28 January 2003
+ Last updated: 09 September 2004
- Copyright (c) 1997-2003 University of Cambridge.
+ Copyright (c) 1997-2004 University of Cambridge.
  -----------------------------------------------------------------------------

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