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

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-revision 83 by nigel,
Sat Feb 24 21:41:06 2007 UTC
+revision 87 by nigel,
Sat Feb 24 21:41:21 2007 UTC
 Line 137 
 UTF-8 AND UNICODE PROPERTY SUPPORT
         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-
+        for a decimal number, the Unicode script names such as Arabic  or  Han,
-        tation. The PCRE library is increased in size by about 90K when Unicode
+        and  the  derived  properties  Any  and L&. A full list is given in the
-        property support is included.
+        pcrepattern documentation. Only the short names for properties are sup-
+        ported.  For example, \p{L} matches a letter. Its Perl synonym, \p{Let-
+        ter}, is not supported.  Furthermore,  in  Perl,  many  properties  may
+        optionally  be  prefixed by "Is", for compatibility with Perl 5.6. PCRE
+        does not support this.
         The following comments apply when PCRE is running in UTF-8 mode:
-Line 155 
 UTF-8 AND UNICODE PROPERTY SUPPORT
+Line 159 
 UTF-8 AND UNICODE PROPERTY SUPPORT
         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
+. An unbraced hexadecimal escape sequence (such  as  \xb3)  matches  a
-        braces  is  a  string  of hexadecimal digits, is interpreted as a UTF-8
+        two-byte UTF-8 character if the value is greater than 127.
-        character whose code number is the given hexadecimal number, for  exam-
-        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
+.  Repeat quantifiers apply to complete UTF-8 characters, not to indi-
-        UTF-8 character if the value is greater than 127.
-. Repeat quantifiers apply to complete UTF-8 characters, not to  indi-
         vidual bytes, for example: \x{100}{3}.
-.  The dot metacharacter matches one UTF-8 character instead of a sin-
+. The dot metacharacter matches one UTF-8 character instead of a  sin-
         gle byte.
-. The escape sequence \C can be used to match a single byte  in  UTF-8
+.  The  escape sequence \C can be used to match a single byte in UTF-8
-        mode,  but  its  use can lead to some strange effects. This facility is
+        mode, but its use can lead to some strange effects.  This  facility  is
         not available in the alternative matching function, pcre_dfa_exec().
-. The character escapes \b, \B, \d, \D, \s, \S, \w, and  \W  correctly
+.  The  character escapes \b, \B, \d, \D, \s, \S, \w, and \W correctly
-        test  characters of any code value, but the characters that PCRE recog-
+        test characters of any code value, but the characters that PCRE  recog-
-        nizes as digits, spaces, or word characters  remain  the  same  set  as
+        nizes  as  digits,  spaces,  or  word characters remain the same set as
         before, all with values less than 256. This remains true even when PCRE
-        includes Unicode property support, because to do otherwise  would  slow
+        includes  Unicode  property support, because to do otherwise would slow
-        down  PCRE in many common cases. If you really want to test for a wider
+        down PCRE in many common cases. If you really want to test for a  wider
-        sense of, say, "digit", you must use Unicode  property  tests  such  as
+        sense  of,  say,  "digit",  you must use Unicode property tests such as
         \p{Nd}.
-.  Similarly,  characters that match the POSIX named character classes
+. Similarly, characters that match the POSIX named  character  classes
         are all low-valued characters.
-. Case-insensitive matching applies only to  characters  whose  values
+.  Case-insensitive  matching  applies only to characters whose values
-        are  less than 128, unless PCRE is built with Unicode property support.
+        are less than 128, unless PCRE is built with Unicode property  support.
-        Even when Unicode property support is available, PCRE  still  uses  its
+        Even  when  Unicode  property support is available, PCRE still uses its
-        own  character  tables when checking the case of low-valued characters,
+        own character tables when checking the case of  low-valued  characters,
-        so as not to degrade performance.  The Unicode property information  is
+        so  as not to degrade performance.  The Unicode property information is
-        used only for characters with higher values.
+        used only for characters with higher values. Even when Unicode property
+        support is available, PCRE supports case-insensitive matching only when
+        there is a one-to-one mapping between a letter's  cases.  There  are  a
+        small  number  of  many-to-one  mappings in Unicode; these are not sup-
+        ported by PCRE.
  AUTHOR
-Line 201 
 AUTHOR
+Line 202 
 AUTHOR
         University Computing Service,
         Cambridge CB2 3QG, England.
-        Putting  an actual email address here seems to have been a spam magnet,
+        Putting an actual email address here seems to have been a spam  magnet,
         so I've taken it away. If you want to email me, use my initial and sur-
         name, separated by a dot, at the domain ucs.cam.ac.uk.
- Last updated: 07 March 2005
+ Last updated: 24 January 2006
- Copyright (c) 1997-2005 University of Cambridge.
+ Copyright (c) 1997-2006 University of Cambridge.
  ------------------------------------------------------------------------------
-Line 808 
 CHECKING BUILD-TIME OPTIONS
+Line 809 
 CHECKING BUILD-TIME OPTIONS
         internal  matching  function  calls in a pcre_exec() execution. Further
         details are given with pcre_exec() below.
+          PCRE_CONFIG_MATCH_LIMIT_RECURSION
+        The output is an integer that gives the default limit for the depth  of
+        recursion  when calling the internal matching function in a pcre_exec()
+        execution. Further details are given with pcre_exec() below.
           PCRE_CONFIG_STACKRECURSE
         The output is an integer that is set to one if internal recursion  when
-Line 861 
 COMPILING A PATTERN
+Line 868 
 COMPILING A PATTERN
         If errptr is NULL, pcre_compile() returns NULL immediately.  Otherwise,
         if  compilation  of  a  pattern fails, pcre_compile() returns NULL, and
         sets the variable pointed to by errptr to point to a textual error mes-
-        sage.  The  offset from the start of the pattern to the character where
+        sage. This is a static string that is part of the library. You must not
-        the error was discovered is  placed  in  the  variable  pointed  to  by
+        try to free it. The offset from the start of the pattern to the charac-
-        erroffset,  which  must  not  be  NULL. If it is, an immediate error is
+        ter where the error was discovered is placed in the variable pointed to
+        by erroffset, which must not be NULL. If it is, an immediate  error  is
         given.
-        If pcre_compile2() is used instead of pcre_compile(),  and  the  error-
+        If  pcre_compile2()  is  used instead of pcre_compile(), and the error-
-        codeptr  argument is not NULL, a non-zero error code number is returned
+        codeptr argument is not NULL, a non-zero error code number is  returned
-        via this argument in the event of an error. This is in addition to  the
+        via  this argument in the event of an error. This is in addition to the
         textual error message. Error codes and messages are listed below.
-        If  the  final  argument, tableptr, is NULL, PCRE uses a default set of
+        If the final argument, tableptr, is NULL, PCRE uses a  default  set  of
-        character tables that are  built  when  PCRE  is  compiled,  using  the
+        character  tables  that  are  built  when  PCRE  is compiled, using the
-        default  C  locale.  Otherwise, tableptr must be an address that is the
+        default C locale. Otherwise, tableptr must be an address  that  is  the
-        result of a call to pcre_maketables(). This value is  stored  with  the
+        result  of  a  call to pcre_maketables(). This value is stored with the
-        compiled  pattern,  and used again by pcre_exec(), unless another table
+        compiled pattern, and used again by pcre_exec(), unless  another  table
         pointer is passed to it. For more discussion, see the section on locale
         support below.
-        This  code  fragment  shows a typical straightforward call to pcre_com-
+        This code fragment shows a typical straightforward  call  to  pcre_com-
         pile():
           pcre *re;
-Line 892 
 COMPILING A PATTERN
+Line 900 
 COMPILING A PATTERN
             &erroffset,       /* for error offset */
             NULL);            /* use default character tables */
-        The following names for option bits are defined in  the  pcre.h  header
+        The  following  names  for option bits are defined in the pcre.h header
         file:
           PCRE_ANCHORED
         If this bit is set, the pattern is forced to be "anchored", that is, it
-        is constrained to match only at the first matching point in the  string
+        is  constrained to match only at the first matching point in the string
-        that  is being searched (the "subject string"). This effect can also be
+        that is being searched (the "subject string"). This effect can also  be
-        achieved by appropriate constructs in the pattern itself, which is  the
+        achieved  by appropriate constructs in the pattern itself, which is the
         only way to do it in Perl.
           PCRE_AUTO_CALLOUT
         If this bit is set, pcre_compile() automatically inserts callout items,
-        all with number 255, before each pattern item. For  discussion  of  the
+        all  with  number  255, before each pattern item. For discussion of the
         callout facility, see the pcrecallout documentation.
           PCRE_CASELESS
-        If  this  bit is set, letters in the pattern match both upper and lower
+        If this bit is set, letters in the pattern match both upper  and  lower
-        case letters. It is equivalent to Perl's  /i  option,  and  it  can  be
+        case  letters.  It  is  equivalent  to  Perl's /i option, and it can be
-        changed  within a pattern by a (?i) option setting. In UTF-8 mode, PCRE
+        changed within a pattern by a (?i) option setting. In UTF-8 mode,  PCRE
-        always understands the concept of case for characters whose values  are
+        always  understands the concept of case for characters whose values are
-        less  than 128, so caseless matching is always possible. For characters
+        less than 128, so caseless matching is always possible. For  characters
-        with higher values, the concept of case is supported if  PCRE  is  com-
+        with  higher  values,  the concept of case is supported if PCRE is com-
-        piled  with Unicode property support, but not otherwise. If you want to
+        piled with Unicode property support, but not otherwise. If you want  to
-        use caseless matching for characters 128 and  above,  you  must  ensure
+        use  caseless  matching  for  characters 128 and above, you must ensure
-        that  PCRE  is  compiled  with Unicode property support as well as with
+        that PCRE is compiled with Unicode property support  as  well  as  with
         UTF-8 support.
           PCRE_DOLLAR_ENDONLY
-        If this bit is set, a dollar metacharacter in the pattern matches  only
+        If  this bit is set, a dollar metacharacter in the pattern matches only
-        at  the  end  of the subject string. Without this option, a dollar also
+        at the end of the subject string. Without this option,  a  dollar  also
-        matches immediately before the final character if it is a newline  (but
+        matches  immediately before the final character if it is a newline (but
-        not  before  any  other  newlines).  The  PCRE_DOLLAR_ENDONLY option is
+        not before any  other  newlines).  The  PCRE_DOLLAR_ENDONLY  option  is
         ignored if PCRE_MULTILINE is set. There is no equivalent to this option
         in Perl, and no way to set it within a pattern.
           PCRE_DOTALL
         If this bit is set, a dot metacharater in the pattern matches all char-
-        acters, including newlines. Without it,  newlines  are  excluded.  This
+        acters,  including  newlines.  Without  it, newlines are excluded. This
-        option  is equivalent to Perl's /s option, and it can be changed within
+        option is equivalent to Perl's /s option, and it can be changed  within
-        a pattern by a (?s) option setting.  A  negative  class  such  as  [^a]
+        a  pattern  by  a  (?s)  option  setting. A negative class such as [^a]
-        always  matches a newline character, independent of the setting of this
+        always matches a newline character, independent of the setting of  this
         option.
           PCRE_EXTENDED
-        If this bit is set, whitespace  data  characters  in  the  pattern  are
+        If  this  bit  is  set,  whitespace  data characters in the pattern are
         totally ignored except when escaped or inside a character class. White-
         space does not include the VT character (code 11). In addition, charac-
         ters between an unescaped # outside a character class and the next new-
-        line character, inclusive, are also  ignored.  This  is  equivalent  to
+        line  character,  inclusive,  are  also  ignored. This is equivalent to
-        Perl's  /x  option,  and  it  can be changed within a pattern by a (?x)
+        Perl's /x option, and it can be changed within  a  pattern  by  a  (?x)
         option setting.
-        This option makes it possible to include  comments  inside  complicated
+        This  option  makes  it possible to include comments inside complicated
-        patterns.   Note,  however,  that this applies only to data characters.
+        patterns.  Note, however, that this applies only  to  data  characters.
-        Whitespace  characters  may  never  appear  within  special   character
+        Whitespace   characters  may  never  appear  within  special  character
-        sequences  in  a  pattern,  for  example  within the sequence (?( which
+        sequences in a pattern, for  example  within  the  sequence  (?(  which
         introduces a conditional subpattern.
           PCRE_EXTRA
-        This option was invented in order to turn on  additional  functionality
+        This  option  was invented in order to turn on additional functionality
-        of  PCRE  that  is  incompatible with Perl, but it is currently of very
+        of PCRE that is incompatible with Perl, but it  is  currently  of  very
-        little use. When set, any backslash in a pattern that is followed by  a
+        little  use. When set, any backslash in a pattern that is followed by a
-        letter  that  has  no  special  meaning causes an error, thus reserving
+        letter that has no special meaning  causes  an  error,  thus  reserving
-        these combinations for future expansion. By  default,  as  in  Perl,  a
+        these  combinations  for  future  expansion.  By default, as in Perl, a
-        backslash  followed by a letter with no special meaning is treated as a
+        backslash followed by a letter with no special meaning is treated as  a
-        literal. There are at present no  other  features  controlled  by  this
+        literal.  There  are  at  present  no other features controlled by this
         option. It can also be set by a (?X) option setting within a pattern.
           PCRE_FIRSTLINE
-        If  this  option  is  set,  an  unanchored pattern is required to match
+        If this option is set, an  unanchored  pattern  is  required  to  match
-        before or at the first newline character in the subject string,  though
+        before  or at the first newline character in the subject string, though
         the matched text may continue over the newline.
           PCRE_MULTILINE
-        By  default,  PCRE  treats the subject string as consisting of a single
+        By default, PCRE treats the subject string as consisting  of  a  single
-        line of characters (even if it actually contains newlines). The  "start
+        line  of characters (even if it actually contains newlines). The "start
-        of  line"  metacharacter  (^)  matches only at the start of the string,
+        of line" metacharacter (^) matches only at the  start  of  the  string,
-        while the "end of line" metacharacter ($) matches only at  the  end  of
+        while  the  "end  of line" metacharacter ($) matches only at the end of
         the string, or before a terminating newline (unless PCRE_DOLLAR_ENDONLY
         is set). This is the same as Perl.
-        When PCRE_MULTILINE it is set, the "start of line" and  "end  of  line"
+        When  PCRE_MULTILINE  it  is set, the "start of line" and "end of line"
-        constructs  match  immediately following or immediately before any new-
+        constructs match immediately following or immediately before  any  new-
-        line in the subject string, respectively, as well as at the very  start
+        line  in the subject string, respectively, as well as at the very start
-        and  end. This is equivalent to Perl's /m option, and it can be changed
+        and end. This is equivalent to Perl's /m option, and it can be  changed
         within a pattern by a (?m) option setting. If there are no "\n" charac-
-        ters  in  a  subject  string, or no occurrences of ^ or $ in a pattern,
+        ters in a subject string, or no occurrences of ^ or  $  in  a  pattern,
         setting PCRE_MULTILINE has no effect.
           PCRE_NO_AUTO_CAPTURE
         If this option is set, it disables the use of numbered capturing paren-
-        theses  in the pattern. Any opening parenthesis that is not followed by
+        theses in the pattern. Any opening parenthesis that is not followed  by
-        ? behaves as if it were followed by ?: but named parentheses can  still
+        ?  behaves as if it were followed by ?: but named parentheses can still
-        be  used  for  capturing  (and  they acquire numbers in the usual way).
+        be used for capturing (and they acquire  numbers  in  the  usual  way).
         There is no equivalent of this option in Perl.
           PCRE_UNGREEDY
-        This option inverts the "greediness" of the quantifiers  so  that  they
+        This  option  inverts  the "greediness" of the quantifiers so that they
-        are  not greedy by default, but become greedy if followed by "?". It is
+        are not greedy by default, but become greedy if followed by "?". It  is
-        not compatible with Perl. It can also be set by a (?U)  option  setting
+        not  compatible  with Perl. It can also be set by a (?U) option setting
         within the pattern.
           PCRE_UTF8
-        This  option  causes PCRE to regard both the pattern and the subject as
+        This option causes PCRE to regard both the pattern and the  subject  as
-        strings of UTF-8 characters instead of single-byte  character  strings.
+        strings  of  UTF-8 characters instead of single-byte character strings.
-        However,  it is available only when PCRE is built to include UTF-8 sup-
+        However, it is available only when PCRE is built to include UTF-8  sup-
-        port. If not, the use of this option provokes an error. Details of  how
+        port.  If not, the use of this option provokes an error. Details of how
-        this  option  changes the behaviour of PCRE are given in the section on
+        this option changes the behaviour of PCRE are given in the  section  on
         UTF-8 support in the main pcre page.
           PCRE_NO_UTF8_CHECK
         When PCRE_UTF8 is set, the validity of the pattern as a UTF-8 string is
-        automatically  checked. If an invalid UTF-8 sequence of bytes is found,
+        automatically checked. If an invalid UTF-8 sequence of bytes is  found,
-        pcre_compile() returns an error. If you already know that your  pattern
+        pcre_compile()  returns an error. If you already know that your pattern
-        is  valid, and you want to skip this check for performance reasons, you
+        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
+        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 this option can  also  be  passed  to
+        your  program  to  crash.   Note that this option can also be passed to
-        pcre_exec()  and pcre_dfa_exec(), to suppress the UTF-8 validity check-
+        pcre_exec() and pcre_dfa_exec(), to suppress the UTF-8 validity  check-
         ing of subject strings.
  COMPILATION ERROR CODES
-        The following table lists the error  codes  than  may  be  returned  by
+        The  following  table  lists  the  error  codes than may be returned by
-        pcre_compile2(),  along with the error messages that may be returned by
+        pcre_compile2(), along with the error messages that may be returned  by
         both compiling functions.
  no error
-Line 1088 
 STUDYING A PATTERN
+Line 1096 
 STUDYING A PATTERN
         pcre_extra *pcre_study(const pcre *code, int options
              const char **errptr);
-        If a compiled pattern is going to be used several times,  it  is  worth
+        If  a  compiled  pattern is going to be used several times, it is worth
         spending more time analyzing it in order to speed up the time taken for
-        matching. The function pcre_study() takes a pointer to a compiled  pat-
+        matching.  The function pcre_study() takes a pointer to a compiled pat-
         tern as its first argument. If studying the pattern produces additional
-        information that will help speed up matching,  pcre_study()  returns  a
+        information  that  will  help speed up matching, pcre_study() returns a
-        pointer  to a pcre_extra block, in which the study_data field points to
+        pointer to a pcre_extra block, in which the study_data field points  to
         the results of the study.
         The  returned  value  from  pcre_study()  can  be  passed  directly  to
-        pcre_exec().  However,  a  pcre_extra  block also contains other fields
+        pcre_exec(). However, a pcre_extra block  also  contains  other  fields
-        that can be set by the caller before the block  is  passed;  these  are
+        that  can  be  set  by the caller before the block is passed; these are
         described below in the section on matching a pattern.
-        If  studying  the  pattern  does not produce any additional information
+        If studying the pattern does not  produce  any  additional  information
         pcre_study() returns NULL. In that circumstance, if the calling program
-        wants  to  pass  any of the other fields to pcre_exec(), it must set up
+        wants to pass any of the other fields to pcre_exec(), it  must  set  up
         its own pcre_extra block.
-        The second argument of pcre_study() contains option bits.  At  present,
+        The  second  argument of pcre_study() contains option bits. At present,
         no options are defined, and this argument should always be zero.
-        The  third argument for pcre_study() is a pointer for an error message.
+        The third argument for pcre_study() is a pointer for an error  message.
-        If studying succeeds (even if no data is  returned),  the  variable  it
+        If  studying  succeeds  (even  if no data is returned), the variable it
-        points  to  is set to NULL. Otherwise it points to a textual error mes-
+        points to is set to NULL. Otherwise it is set to  point  to  a  textual
-        sage. You should therefore test the error pointer for NULL after  call-
+        error message. This is a static string that is part of the library. You
-        ing pcre_study(), to be sure that it has run successfully.
+        must not try to free it. You should test the  error  pointer  for  NULL
+        after calling pcre_study(), to be sure that it has run successfully.
         This is a typical call to pcre_study():
-Line 1135 
 LOCALE SUPPORT
+Line 1144 
 LOCALE SUPPORT
         by  character  value.  When running in UTF-8 mode, this applies only to
         characters with codes less than 128. Higher-valued  codes  never  match
         escapes  such  as  \w or \d, but can be tested with \p if PCRE is built
-        with Unicode character property support.
+        with Unicode character property support. The use of locales  with  Uni-
+        code is discouraged.
-        An internal set of tables is created in the default C locale when  PCRE
+        An  internal set of tables is created in the default C locale when PCRE
-        is  built.  This  is  used when the final argument of pcre_compile() is
+        is built. This is used when the final  argument  of  pcre_compile()  is
-        NULL, and is sufficient for many applications. An  alternative  set  of
+        NULL,  and  is  sufficient for many applications. An alternative set of
-        tables  can,  however, be supplied. These may be created in a different
+        tables can, however, be supplied. These may be created in  a  different
-        locale from the default. As more and more applications change to  using
+        locale  from the default. As more and more applications change to using
         Unicode, the need for this locale support is expected to die away.
-        External  tables  are  built by calling the pcre_maketables() function,
+        External tables are built by calling  the  pcre_maketables()  function,
-        which has no arguments, in the relevant locale. The result can then  be
+        which  has no arguments, in the relevant locale. The result can then be
-        passed  to  pcre_compile()  or  pcre_exec()  as often as necessary. For
+        passed to pcre_compile() or pcre_exec()  as  often  as  necessary.  For
-        example, to build and use tables that are appropriate  for  the  French
+        example,  to  build  and use tables that are appropriate for the French
-        locale  (where  accented  characters  with  values greater than 128 are
+        locale (where accented characters with  values  greater  than  128  are
         treated as letters), the following code could be used:
           setlocale(LC_CTYPE, "fr_FR");
           tables = pcre_maketables();
           re = pcre_compile(..., tables);
-        When pcre_maketables() runs, the tables are built  in  memory  that  is
+        When  pcre_maketables()  runs,  the  tables are built in memory that is
-        obtained  via  pcre_malloc. It is the caller's responsibility to ensure
+        obtained via pcre_malloc. It is the caller's responsibility  to  ensure
-        that the memory containing the tables remains available for as long  as
+        that  the memory containing the tables remains available for as long as
         it is needed.
         The pointer that is passed to pcre_compile() is saved with the compiled
-        pattern, and the same tables are used via this pointer by  pcre_study()
+        pattern,  and the same tables are used via this pointer by pcre_study()
         and normally also by pcre_exec(). Thus, by default, for any single pat-
         tern, compilation, studying and matching all happen in the same locale,
         but different patterns can be compiled in different locales.
-        It  is  possible to pass a table pointer or NULL (indicating the use of
+        It is possible to pass a table pointer or NULL (indicating the  use  of
-        the internal tables) to pcre_exec(). Although  not  intended  for  this
+        the  internal  tables)  to  pcre_exec(). Although not intended for this
-        purpose,  this facility could be used to match a pattern in a different
+        purpose, this facility could be used to match a pattern in a  different
         locale from the one in which it was compiled. Passing table pointers at
         run time is discussed below in the section on matching a pattern.
-Line 1178 
 INFORMATION ABOUT A PATTERN
+Line 1188 
 INFORMATION ABOUT A PATTERN
         int pcre_fullinfo(const pcre *code, const pcre_extra *extra,
              int what, void *where);
-        The  pcre_fullinfo() function returns information about a compiled pat-
+        The pcre_fullinfo() function returns information about a compiled  pat-
         tern. It replaces the obsolete pcre_info() function, which is neverthe-
         less retained for backwards compability (and is documented below).
-        The  first  argument  for  pcre_fullinfo() is a pointer to the compiled
+        The first argument for pcre_fullinfo() is a  pointer  to  the  compiled
-        pattern. The second argument is the result of pcre_study(), or NULL  if
+        pattern.  The second argument is the result of pcre_study(), or NULL if
-        the  pattern  was not studied. The third argument specifies which piece
+        the pattern was not studied. The third argument specifies  which  piece
-        of information is required, and the fourth argument is a pointer  to  a
+        of  information  is required, and the fourth argument is a pointer to a
-        variable  to  receive  the  data. The yield of the function is zero for
+        variable to receive the data. The yield of the  function  is  zero  for
         success, or one of the following negative numbers:
           PCRE_ERROR_NULL       the argument code was NULL
-Line 1194 
 INFORMATION ABOUT A PATTERN
+Line 1204 
 INFORMATION ABOUT A PATTERN
           PCRE_ERROR_BADMAGIC   the "magic number" was not found
           PCRE_ERROR_BADOPTION  the value of what was invalid
-        The "magic number" is placed at the start of each compiled  pattern  as
+        The  "magic  number" is placed at the start of each compiled pattern as
-        an  simple check against passing an arbitrary memory pointer. Here is a
+        an simple check against passing an arbitrary memory pointer. Here is  a
-        typical call of pcre_fullinfo(), to obtain the length of  the  compiled
+        typical  call  of pcre_fullinfo(), to obtain the length of the compiled
         pattern:
           int rc;
-Line 1207 
 INFORMATION ABOUT A PATTERN
+Line 1217 
 INFORMATION ABOUT A PATTERN
             PCRE_INFO_SIZE,   /* what is required */
             &length);         /* where to put the data */
-        The  possible  values for the third argument are defined in pcre.h, and
+        The possible values for the third argument are defined in  pcre.h,  and
         are as follows:
           PCRE_INFO_BACKREFMAX
-        Return the number of the highest back reference  in  the  pattern.  The
+        Return  the  number  of  the highest back reference in the pattern. The
-        fourth  argument  should  point to an int variable. Zero is returned if
+        fourth argument should point to an int variable. Zero  is  returned  if
         there are no back references.
           PCRE_INFO_CAPTURECOUNT
-        Return the number of capturing subpatterns in the pattern.  The  fourth
+        Return  the  number of capturing subpatterns in the pattern. The fourth
         argument should point to an int variable.
           PCRE_INFO_DEFAULT_TABLES
-        Return  a pointer to the internal default character tables within PCRE.
+        Return a pointer to the internal default character tables within  PCRE.
-        The fourth argument should point to an unsigned char *  variable.  This
+        The  fourth  argument should point to an unsigned char * variable. This
         information call is provided for internal use by the pcre_study() func-
-        tion. External callers can cause PCRE to use  its  internal  tables  by
+        tion.  External  callers  can  cause PCRE to use its internal tables by
         passing a NULL table pointer.
           PCRE_INFO_FIRSTBYTE
-        Return  information  about  the first byte of any matched string, for a
+        Return information about the first byte of any matched  string,  for  a
-        non-anchored   pattern.   (This    option    used    to    be    called
+        non-anchored    pattern.    (This    option    used    to   be   called
-        PCRE_INFO_FIRSTCHAR;  the  old  name  is still recognized for backwards
+        PCRE_INFO_FIRSTCHAR; the old name is  still  recognized  for  backwards
         compatibility.)
-        If there is a fixed first byte, for example, from  a  pattern  such  as
+        If  there  is  a  fixed first byte, for example, from a pattern such as
-        (cat|cow|coyote),  it  is  returned in the integer pointed to by where.
+        (cat|cow|coyote), it is returned in the integer pointed  to  by  where.
         Otherwise, if either
-        (a) the pattern was compiled with the PCRE_MULTILINE option, and  every
+        (a)  the pattern was compiled with the PCRE_MULTILINE option, and every
         branch starts with "^", or
         (b) every branch of the pattern starts with ".*" and PCRE_DOTALL is not
         set (if it were set, the pattern would be anchored),
-        -1 is returned, indicating that the pattern matches only at  the  start
+        -1  is  returned, indicating that the pattern matches only at the start
-        of  a  subject string or after any newline within the string. Otherwise
+        of a subject string or after any newline within the  string.  Otherwise
         -2 is returned. For anchored patterns, -2 is returned.
           PCRE_INFO_FIRSTTABLE
-        If the pattern was studied, and this resulted in the construction of  a
+        If  the pattern was studied, and this resulted in the construction of a
 -bit table indicating a fixed set of bytes for the first byte in any
-        matching string, a pointer to the table is returned. Otherwise NULL  is
+        matching  string, a pointer to the table is returned. Otherwise NULL is
-        returned.  The fourth argument should point to an unsigned char * vari-
+        returned. The fourth argument should point to an unsigned char *  vari-
         able.
           PCRE_INFO_LASTLITERAL
-        Return the value of the rightmost literal byte that must exist  in  any
+        Return  the  value of the rightmost literal byte that must exist in any
-        matched  string,  other  than  at  its  start,  if such a byte has been
+        matched string, other than at its  start,  if  such  a  byte  has  been
         recorded. The fourth argument should point to an int variable. If there
-        is  no such byte, -1 is returned. For anchored patterns, a last literal
+        is no such byte, -1 is returned. For anchored patterns, a last  literal
-        byte is recorded only if it follows something of variable  length.  For
+        byte  is  recorded only if it follows something of variable length. For
         example, for the pattern /^a\d+z\d+/ the returned value is "z", but for
         /^a\dz\d/ the returned value is -1.
-Line 1272 
 INFORMATION ABOUT A PATTERN
+Line 1282 
 INFORMATION ABOUT A PATTERN
           PCRE_INFO_NAMEENTRYSIZE
           PCRE_INFO_NAMETABLE
-        PCRE supports the use of named as well as numbered capturing  parenthe-
+        PCRE  supports the use of named as well as numbered capturing parenthe-
-        ses.  The names are just an additional way of identifying the parenthe-
+        ses. The names are just an additional way of identifying the  parenthe-
         ses,  which  still  acquire  numbers.  A  convenience  function  called
-        pcre_get_named_substring()  is  provided  for  extracting an individual
+        pcre_get_named_substring() is provided  for  extracting  an  individual
-        captured substring by name. It is also possible  to  extract  the  data
+        captured  substring  by  name.  It is also possible to extract the data
-        directly,  by  first converting the name to a number in order to access
+        directly, by first converting the name to a number in order  to  access
-        the correct pointers in the output vector (described  with  pcre_exec()
+        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,
+        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
-        of each entry; both of these  return  an  int  value.  The  entry  size
+        of  each  entry;  both  of  these  return  an int value. The entry size
-        depends  on the length of the longest name. PCRE_INFO_NAMETABLE returns
+        depends on the length of the longest name. PCRE_INFO_NAMETABLE  returns
-        a pointer to the first entry of the table  (a  pointer  to  char).  The
+        a  pointer  to  the  first  entry of the table (a pointer to char). The
         first two bytes of each entry are the number of the capturing parenthe-
-        sis, most significant byte first. The rest of the entry is  the  corre-
+        sis,  most  significant byte first. The rest of the entry is the corre-
-        sponding  name,  zero  terminated. The names are in alphabetical order.
+        sponding name, zero terminated. The names are  in  alphabetical  order.
-        For example, consider the following pattern  (assume  PCRE_EXTENDED  is
+        For  example,  consider  the following pattern (assume PCRE_EXTENDED is
         set, so white space - including newlines - is ignored):
           (?P<date> (?P<year>(\d\d)?\d\d) -
           (?P<month>\d\d) - (?P<day>\d\d) )
-        There  are  four  named subpatterns, so the table has four entries, and
+        There are four named subpatterns, so the table has  four  entries,  and
-        each entry in the table is eight bytes long. The table is  as  follows,
+        each  entry  in the table is eight bytes long. The table is as follows,
         with non-printing bytes shows in hexadecimal, and undefined bytes shown
         as ??:
-Line 1306 
 INFORMATION ABOUT A PATTERN
+Line 1316 
 INFORMATION ABOUT A PATTERN
 04 m  o  n  t  h  00
 02 y  e  a  r  00 ??
-        When writing code to extract data  from  named  subpatterns  using  the
+        When  writing  code  to  extract  data from named subpatterns using the
         name-to-number map, remember that the length of each entry is likely to
         be different for each compiled pattern.
           PCRE_INFO_OPTIONS
-        Return a copy of the options with which the pattern was  compiled.  The
+        Return  a  copy of the options with which the pattern was compiled. The
-        fourth  argument  should  point to an unsigned long int variable. These
+        fourth argument should point to an unsigned long  int  variable.  These
         option bits are those specified in the call to pcre_compile(), modified
         by any top-level option settings within the pattern itself.
-        A  pattern  is  automatically  anchored by PCRE if all of its top-level
+        A pattern is automatically anchored by PCRE if  all  of  its  top-level
         alternatives begin with one of the following:
           ^     unless PCRE_MULTILINE is set
-Line 1331 
 INFORMATION ABOUT A PATTERN
+Line 1341 
 INFORMATION ABOUT A PATTERN
           PCRE_INFO_SIZE
-        Return  the  size  of the compiled pattern, that is, the value that was
+        Return the size of the compiled pattern, that is, the  value  that  was
         passed as the argument to pcre_malloc() when PCRE was getting memory in
         which to place the compiled data. The fourth argument should point to a
         size_t variable.
-Line 1339 
 INFORMATION ABOUT A PATTERN
+Line 1349 
 INFORMATION ABOUT A PATTERN
           PCRE_INFO_STUDYSIZE
         Return the size of the data block pointed to by the study_data field in
-        a  pcre_extra  block.  That  is,  it  is  the  value that was passed to
+        a pcre_extra block. That is,  it  is  the  value  that  was  passed  to
         pcre_malloc() when PCRE was getting memory into which to place the data
-        created  by  pcre_study(). The fourth argument should point to a size_t
+        created by pcre_study(). The fourth argument should point to  a  size_t
         variable.
-Line 1349 
 OBSOLETE INFO FUNCTION
+Line 1359 
 OBSOLETE INFO FUNCTION
         int pcre_info(const pcre *code, int *optptr, int *firstcharptr);
-        The pcre_info() function is now obsolete because its interface  is  too
+        The  pcre_info()  function is now obsolete because its interface is too
-        restrictive  to return all the available data about a compiled pattern.
+        restrictive to return all the available data about a compiled  pattern.
-        New  programs  should  use  pcre_fullinfo()  instead.  The   yield   of
+        New   programs   should  use  pcre_fullinfo()  instead.  The  yield  of
-        pcre_info()  is the number of capturing subpatterns, or one of the fol-
+        pcre_info() is the number of capturing subpatterns, or one of the  fol-
         lowing negative numbers:
           PCRE_ERROR_NULL       the argument code was NULL
           PCRE_ERROR_BADMAGIC   the "magic number" was not found
-        If the optptr argument is not NULL, a copy of the  options  with  which
+        If  the  optptr  argument is not NULL, a copy of the options with which
-        the  pattern  was  compiled  is placed in the integer it points to (see
+        the pattern was compiled is placed in the integer  it  points  to  (see
         PCRE_INFO_OPTIONS above).
-        If the pattern is not anchored and the  firstcharptr  argument  is  not
+        If  the  pattern  is  not anchored and the firstcharptr argument is not
-        NULL,  it is used to pass back information about the first character of
+        NULL, it is used to pass back information about the first character  of
         any matched string (see PCRE_INFO_FIRSTBYTE above).
-Line 1371 
 REFERENCE COUNTS
+Line 1381 
 REFERENCE COUNTS
         int pcre_refcount(pcre *code, int adjust);
-        The pcre_refcount() function is used to maintain a reference  count  in
+        The  pcre_refcount()  function is used to maintain a reference count in
         the data block that contains a compiled pattern. It is provided for the
-        benefit of applications that  operate  in  an  object-oriented  manner,
+        benefit  of  applications  that  operate  in an object-oriented manner,
         where different parts of the application may be using the same compiled
         pattern, but you want to free the block when they are all done.
         When a pattern is compiled, the reference count field is initialized to
-        zero.   It is changed only by calling this function, whose action is to
+        zero.  It is changed only by calling this function, whose action is  to
-        add the adjust value (which may be positive or  negative)  to  it.  The
+        add  the  adjust  value  (which may be positive or negative) to it. The
         yield of the function is the new value. However, the value of the count
-        is constrained to lie between 0 and 65535, inclusive. If the new  value
+        is  constrained to lie between 0 and 65535, inclusive. If the new value
         is outside these limits, it is forced to the appropriate limit value.
-        Except  when it is zero, the reference count is not correctly preserved
+        Except when it is zero, the reference count is not correctly  preserved
-        if a pattern is compiled on one host and then  transferred  to  a  host
+        if  a  pattern  is  compiled on one host and then transferred to a host
         whose byte-order is different. (This seems a highly unlikely scenario.)
-Line 1395 
 MATCHING A PATTERN: THE TRADITIONAL FUNC
+Line 1405 
 MATCHING A PATTERN: THE TRADITIONAL FUNC
              const char *subject, int length, int startoffset,
              int options, int *ovector, int ovecsize);
-        The function pcre_exec() is called to match a subject string against  a
+        The  function pcre_exec() is called to match a subject string against a
-        compiled  pattern, which is passed in the code argument. If the pattern
+        compiled pattern, which is passed in the code argument. If the  pattern
         has been studied, the result of the study should be passed in the extra
-        argument.  This  function is the main matching facility of the library,
+        argument. This function is the main matching facility of  the  library,
         and it operates in a Perl-like manner. For specialist use there is also
-        an  alternative matching function, which is described below in the sec-
+        an alternative matching function, which is described below in the  sec-
         tion about the pcre_dfa_exec() function.
-        In most applications, the pattern will have been compiled (and  option-
+        In  most applications, the pattern will have been compiled (and option-
-        ally  studied)  in the same process that calls pcre_exec(). However, it
+        ally studied) in the same process that calls pcre_exec().  However,  it
         is possible to save compiled patterns and study data, and then use them
-        later  in  different processes, possibly even on different hosts. For a
+        later in different processes, possibly even on different hosts.  For  a
         discussion about this, see the pcreprecompile documentation.
         Here is an example of a simple call to pcre_exec():
-Line 1425 
 MATCHING A PATTERN: THE TRADITIONAL FUNC
+Line 1435 
 MATCHING A PATTERN: THE TRADITIONAL FUNC
     Extra data for pcre_exec()
-        If the extra argument is not NULL, it must point to a  pcre_extra  data
+        If  the  extra argument is not NULL, it must point to a pcre_extra data
-        block.  The pcre_study() function returns such a block (when it doesn't
+        block. The pcre_study() function returns such a block (when it  doesn't
-        return NULL), but you can also create one for yourself, and pass  addi-
+        return  NULL), but you can also create one for yourself, and pass addi-
-        tional  information in it. The fields in a pcre_extra block are as fol-
+        tional information in it. The pcre_extra block contains  the  following
-        lows:
+        fields (not necessarily in this order):
           unsigned long int flags;
           void *study_data;
           unsigned long int match_limit;
+          unsigned long int match_limit_recursion;
           void *callout_data;
           const unsigned char *tables;
-        The flags field is a bitmap that specifies which of  the  other  fields
+        The  flags  field  is a bitmap that specifies which of the other fields
         are set. The flag bits are:
           PCRE_EXTRA_STUDY_DATA
           PCRE_EXTRA_MATCH_LIMIT
+          PCRE_EXTRA_MATCH_LIMIT_RECURSION
           PCRE_EXTRA_CALLOUT_DATA
           PCRE_EXTRA_TABLES
-        Other  flag  bits should be set to zero. The study_data field is set in
+        Other flag bits should be set to zero. The study_data field is  set  in
-        the pcre_extra block that is returned by  pcre_study(),  together  with
+        the  pcre_extra  block  that is returned by pcre_study(), together with
         the appropriate flag bit. You should not set this yourself, but you may
-        add to the block by setting the other fields  and  their  corresponding
+        add  to  the  block by setting the other fields and their corresponding
         flag bits.
         The match_limit field provides a means of preventing PCRE from using up
-        a vast amount of resources when running patterns that are not going  to
+        a  vast amount of resources when running patterns that are not going to
-        match,  but  which  have  a very large number of possibilities in their
+        match, but which have a very large number  of  possibilities  in  their
-        search trees. The classic  example  is  the  use  of  nested  unlimited
+        search  trees.  The  classic  example  is  the  use of nested unlimited
         repeats.
-        Internally,  PCRE uses a function called match() which it calls repeat-
+        Internally, PCRE uses a function called match() which it calls  repeat-
-        edly (sometimes recursively). The limit is imposed  on  the  number  of
+        edly  (sometimes  recursively). The limit set by match_limit is imposed
-        times  this  function is called during a match, which has the effect of
+        on the number of times this function is called during  a  match,  which
-        limiting the amount of recursion and backtracking that can take  place.
+        has  the  effect  of  limiting the amount of backtracking that can take
-        For patterns that are not anchored, the count starts from zero for each
+        place. For patterns that are not anchored, the count restarts from zero
-        position in the subject string.
+        for each position in the subject string.
-        The default limit for the library can be set when PCRE  is  built;  the
+        The  default  value  for  the  limit can be set when PCRE is built; the
-        default  default  is 10 million, which handles all but the most extreme
+        default default is 10 million, which handles all but the  most  extreme
-        cases. You can reduce  the  default  by  suppling  pcre_exec()  with  a
+        cases.  You  can  override  the  default by suppling pcre_exec() with a
-        pcre_extra  block  in  which match_limit is set to a smaller value, and
+        pcre_extra    block    in    which    match_limit    is    set,     and
-        PCRE_EXTRA_MATCH_LIMIT is set in the  flags  field.  If  the  limit  is
+        PCRE_EXTRA_MATCH_LIMIT  is  set  in  the  flags  field. If the limit is
         exceeded, pcre_exec() returns PCRE_ERROR_MATCHLIMIT.
-        The  pcre_callout  field is used in conjunction with the "callout" fea-
+        The match_limit_recursion field is similar to match_limit, but  instead
+        of limiting the total number of times that match() is called, it limits
+        the depth of recursion. The recursion depth is a  smaller  number  than
+        the  total number of calls, because not all calls to match() are recur-
+        sive.  This limit is of use only if it is set smaller than match_limit.
+        Limiting  the  recursion  depth  limits the amount of stack that can be
+        used, or, when PCRE has been compiled to use memory on the heap instead
+        of the stack, the amount of heap memory that can be used.
+        The  default  value  for  match_limit_recursion can be set when PCRE is
+        built; the default default  is  the  same  value  as  the  default  for
+        match_limit.  You can override the default by suppling pcre_exec() with
+        a  pcre_extra  block  in  which  match_limit_recursion  is   set,   and
+        PCRE_EXTRA_MATCH_LIMIT_RECURSION  is  set  in  the  flags field. If the
+        limit is exceeded, pcre_exec() returns PCRE_ERROR_RECURSIONLIMIT.
+        The pcre_callout field is used in conjunction with the  "callout"  fea-
         ture, which is described in the pcrecallout documentation.
-        The tables field  is  used  to  pass  a  character  tables  pointer  to
+        The  tables  field  is  used  to  pass  a  character  tables pointer to
-        pcre_exec();  this overrides the value that is stored with the compiled
+        pcre_exec(); this overrides the value that is stored with the  compiled
-        pattern. A non-NULL value is stored with the compiled pattern  only  if
+        pattern.  A  non-NULL value is stored with the compiled pattern only if
-        custom  tables  were  supplied to pcre_compile() via its tableptr argu-
+        custom tables were supplied to pcre_compile() via  its  tableptr  argu-
         ment.  If NULL is passed to pcre_exec() using this mechanism, it forces
-        PCRE's  internal  tables  to be used. This facility is helpful when re-
+        PCRE's internal tables to be used. This facility is  helpful  when  re-
-        using patterns that have been saved after compiling  with  an  external
+        using  patterns  that  have been saved after compiling with an external
-        set  of  tables,  because  the  external tables might be at a different
+        set of tables, because the external tables  might  be  at  a  different
-        address when pcre_exec() is called. See the  pcreprecompile  documenta-
+        address  when  pcre_exec() is called. See the pcreprecompile documenta-
         tion for a discussion of saving compiled patterns for later use.
     Option bits for pcre_exec()
-        The  unused  bits of the options argument for pcre_exec() must be zero.
+        The unused bits of the options argument for pcre_exec() must  be  zero.
-        The  only  bits  that  may  be  set  are  PCRE_ANCHORED,   PCRE_NOTBOL,
+        The   only  bits  that  may  be  set  are  PCRE_ANCHORED,  PCRE_NOTBOL,
         PCRE_NOTEOL, PCRE_NOTEMPTY, PCRE_NO_UTF8_CHECK and PCRE_PARTIAL.
           PCRE_ANCHORED
-        The  PCRE_ANCHORED  option  limits pcre_exec() to matching at the first
+        The PCRE_ANCHORED option limits pcre_exec() to matching  at  the  first
-        matching position. If a pattern was  compiled  with  PCRE_ANCHORED,  or
+        matching  position.  If  a  pattern was compiled with PCRE_ANCHORED, or
-        turned  out to be anchored by virtue of its contents, it cannot be made
+        turned out to be anchored by virtue of its contents, it cannot be  made
         unachored at matching time.
           PCRE_NOTBOL
         This option specifies that first character of the subject string is not
-        the  beginning  of  a  line, so the circumflex metacharacter should not
+        the beginning of a line, so the  circumflex  metacharacter  should  not
-        match before it. Setting this without PCRE_MULTILINE (at compile  time)
+        match  before it. Setting this without PCRE_MULTILINE (at compile time)
-        causes  circumflex  never to match. This option affects only the behav-
+        causes circumflex never to match. This option affects only  the  behav-
         iour of the circumflex metacharacter. It does not affect \A.
           PCRE_NOTEOL
         This option specifies that the end of the subject string is not the end
-        of  a line, so the dollar metacharacter should not match it nor (except
+        of a line, so the dollar metacharacter should not match it nor  (except
-        in multiline mode) a newline immediately before it. Setting this  with-
+        in  multiline mode) a newline immediately before it. Setting this with-
         out PCRE_MULTILINE (at compile time) causes dollar never to match. This
-        option affects only the behaviour of the dollar metacharacter. It  does
+        option  affects only the behaviour of the dollar metacharacter. It does
         not affect \Z or \z.
           PCRE_NOTEMPTY
         An empty string is not considered to be a valid match if this option is
-        set. If there are alternatives in the pattern, they are tried.  If  all
+        set.  If  there are alternatives in the pattern, they are tried. If all
-        the  alternatives  match  the empty string, the entire match fails. For
+        the alternatives match the empty string, the entire  match  fails.  For
         example, if the pattern
           a?b?
-        is applied to a string not beginning with "a" or "b",  it  matches  the
+        is  applied  to  a string not beginning with "a" or "b", it matches the
-        empty  string at the start of the subject. With PCRE_NOTEMPTY set, this
+        empty string at the start of the subject. With PCRE_NOTEMPTY set,  this
         match is not valid, so PCRE searches further into the string for occur-
         rences of "a" or "b".
         Perl has no direct equivalent of PCRE_NOTEMPTY, but it does make a spe-
-        cial case of a pattern match of the empty  string  within  its  split()
+        cial  case  of  a  pattern match of the empty string within its split()
-        function,  and  when  using  the /g modifier. It is possible to emulate
+        function, and when using the /g modifier. It  is  possible  to  emulate
         Perl's behaviour after matching a null string by first trying the match
         again at the same offset with PCRE_NOTEMPTY and PCRE_ANCHORED, and then
-        if that fails by advancing the starting offset (see below)  and  trying
+        if  that  fails by advancing the starting offset (see below) and trying
         an ordinary match again. There is some code that demonstrates how to do
         this in the pcredemo.c sample program.
           PCRE_NO_UTF8_CHECK
         When PCRE_UTF8 is set at compile time, the validity of the subject as a
-        UTF-8  string is automatically checked when pcre_exec() is subsequently
+        UTF-8 string is automatically checked when pcre_exec() is  subsequently
-        called.  The value of startoffset is also checked  to  ensure  that  it
+        called.   The  value  of  startoffset is also checked to ensure that it
-        points  to the start of a UTF-8 character. If an invalid UTF-8 sequence
+        points to the start of a UTF-8 character. 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
+        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
+        If  you  already  know that your subject is valid, and you want to skip
-        these    checks    for   performance   reasons,   you   can   set   the
+        these   checks   for   performance   reasons,   you   can    set    the
-        PCRE_NO_UTF8_CHECK option when calling pcre_exec(). You might  want  to
+        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
+        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
+        making  repeated  calls  to  find  all  the matches in a single subject
-        string.  However,  you  should  be  sure  that the value of startoffset
+        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
+        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
+        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-
+        value  of startoffset that does not point to the start of a UTF-8 char-
         acter, is undefined. Your program may crash.
           PCRE_PARTIAL
-        This  option  turns  on  the  partial  matching feature. If the subject
+        This option turns on the  partial  matching  feature.  If  the  subject
-        string fails to match the pattern, but at some point during the  match-
+        string  fails to match the pattern, but at some point during the match-
-        ing  process  the  end of the subject was reached (that is, the subject
+        ing process the end of the subject was reached (that  is,  the  subject
-        partially matches the pattern and the failure to  match  occurred  only
+        partially  matches  the  pattern and the failure to match occurred only
-        because  there were not enough subject characters), pcre_exec() returns
+        because there were not enough subject characters), pcre_exec()  returns
-        PCRE_ERROR_PARTIAL instead of PCRE_ERROR_NOMATCH. When PCRE_PARTIAL  is
+        PCRE_ERROR_PARTIAL  instead of PCRE_ERROR_NOMATCH. When PCRE_PARTIAL is
-        used,  there  are restrictions on what may appear in the pattern. These
+        used, there are restrictions on what may appear in the  pattern.  These
         are discussed in the pcrepartial documentation.
     The string to be matched by pcre_exec()
-        The subject string is passed to pcre_exec() as a pointer in subject,  a
+        The  subject string is passed to pcre_exec() as a pointer in subject, a
-        length  in  length, and a starting byte offset in startoffset. In UTF-8
+        length in length, and a starting byte offset in startoffset.  In  UTF-8
-        mode, the byte offset must point to the start  of  a  UTF-8  character.
+        mode,  the  byte  offset  must point to the start of a UTF-8 character.
-        Unlike  the  pattern string, the subject may contain binary zero bytes.
+        Unlike the pattern string, the subject may contain binary  zero  bytes.
-        When the starting offset is zero, the search for a match starts at  the
+        When  the starting offset is zero, the search for a match starts at the
         beginning of the subject, and this is by far the most common case.
-        A  non-zero  starting offset is useful when searching for another match
+        A non-zero starting offset is useful when searching for  another  match
-        in the same subject by calling pcre_exec() again after a previous  suc-
+        in  the same subject by calling pcre_exec() again after a previous suc-
-        cess.   Setting  startoffset differs from just passing over a shortened
+        cess.  Setting startoffset differs from just passing over  a  shortened
-        string and setting PCRE_NOTBOL in the case of  a  pattern  that  begins
+        string  and  setting  PCRE_NOTBOL  in the case of a pattern that begins
         with any kind of lookbehind. For example, consider the pattern
           \Biss\B
-        which  finds  occurrences  of "iss" in the middle of words. (\B matches
+        which finds occurrences of "iss" in the middle of  words.  (\B  matches
-        only if the current position in the subject is not  a  word  boundary.)
+        only  if  the  current position in the subject is not a word boundary.)
-        When  applied  to the string "Mississipi" the first call to pcre_exec()
+        When applied to the string "Mississipi" the first call  to  pcre_exec()
-        finds the first occurrence. If pcre_exec() is called  again  with  just
+        finds  the  first  occurrence. If pcre_exec() is called again with just
-        the  remainder  of  the  subject,  namely  "issipi", it does not match,
+        the remainder of the subject,  namely  "issipi",  it  does  not  match,
         because \B is always false at the start of the subject, which is deemed
-        to  be  a  word  boundary. However, if pcre_exec() is passed the entire
+        to be a word boundary. However, if pcre_exec()  is  passed  the  entire
         string again, but with startoffset set to 4, it finds the second occur-
-        rence  of "iss" because it is able to look behind the starting point to
+        rence of "iss" because it is able to look behind the starting point  to
         discover that it is preceded by a letter.
-        If a non-zero starting offset is passed when the pattern  is  anchored,
+        If  a  non-zero starting offset is passed when the pattern is anchored,
         one attempt to match at the given offset is made. This can only succeed
-        if the pattern does not require the match to be at  the  start  of  the
+        if  the  pattern  does  not require the match to be at the start of the
         subject.
     How pcre_exec() returns captured substrings
-        In  general, a pattern matches a certain portion of the subject, and in
+        In general, a pattern matches a certain portion of the subject, and  in
-        addition, further substrings from the subject  may  be  picked  out  by
+        addition,  further  substrings  from  the  subject may be picked out by
-        parts  of  the  pattern.  Following the usage in Jeffrey Friedl's book,
+        parts of the pattern. Following the usage  in  Jeffrey  Friedl's  book,
-        this is called "capturing" in what follows, and the  phrase  "capturing
+        this  is  called "capturing" in what follows, and the phrase "capturing
-        subpattern"  is  used for a fragment of a pattern that picks out a sub-
+        subpattern" is used for a fragment of a pattern that picks out  a  sub-
-        string. PCRE supports several other kinds of  parenthesized  subpattern
+        string.  PCRE  supports several other kinds of parenthesized subpattern
         that do not cause substrings to be captured.
-        Captured  substrings are returned to the caller via a vector of integer
+        Captured substrings are returned to the caller via a vector of  integer
-        offsets whose address is passed in ovector. The number of  elements  in
+        offsets  whose  address is passed in ovector. The number of elements in
-        the  vector is passed in ovecsize, which must be a non-negative number.
+        the vector is passed in ovecsize, which must be a non-negative  number.
         Note: this argument is NOT the size of ovector in bytes.
-        The first two-thirds of the vector is used to pass back  captured  sub-
+        The  first  two-thirds of the vector is used to pass back captured sub-
-        strings,  each  substring using a pair of integers. The remaining third
+        strings, each substring using a pair of integers. The  remaining  third
-        of the vector is used as workspace by pcre_exec() while  matching  cap-
+        of  the  vector is used as workspace by pcre_exec() while matching cap-
-        turing  subpatterns, and is not available for passing back information.
+        turing subpatterns, and is not available for passing back  information.
-        The length passed in ovecsize should always be a multiple of three.  If
+        The  length passed in ovecsize should always be a multiple of three. If
         it is not, it is rounded down.
-        When  a  match  is successful, information about captured substrings is
+        When a match is successful, information about  captured  substrings  is
-        returned in pairs of integers, starting at the  beginning  of  ovector,
+        returned  in  pairs  of integers, starting at the beginning of ovector,
-        and  continuing  up  to two-thirds of its length at the most. The first
+        and continuing up to two-thirds of its length at the  most.  The  first
         element of a pair is set to the offset of the first character in a sub-
-        string,  and  the  second  is  set to the offset of the first character
+        string, and the second is set to the  offset  of  the  first  character
-        after the end of a substring. The  first  pair,  ovector[0]  and  ovec-
+        after  the  end  of  a  substring. The first pair, ovector[0] and ovec-
-        tor[1],  identify  the  portion  of  the  subject string matched by the
+        tor[1], identify the portion of  the  subject  string  matched  by  the
-        entire pattern. The next pair is used for the first  capturing  subpat-
+        entire  pattern.  The next pair is used for the first capturing subpat-
-        tern,  and  so  on.  The value returned by pcre_exec() is the number of
+        tern, and so on. The value returned by pcre_exec()  is  the  number  of
-        pairs that have been set. If there are no  capturing  subpatterns,  the
+        pairs  that  have  been set. If there are no capturing subpatterns, the
-        return  value  from  a  successful match is 1, indicating that just the
+        return value from a successful match is 1,  indicating  that  just  the
         first pair of offsets has been set.
-        Some convenience functions are provided  for  extracting  the  captured
+        Some  convenience  functions  are  provided for extracting the captured
-        substrings  as  separate  strings. These are described in the following
+        substrings as separate strings. These are described  in  the  following
         section.
-        It is possible for an capturing subpattern number  n+1  to  match  some
+        It  is  possible  for  an capturing subpattern number n+1 to match some
-        part  of  the  subject  when subpattern n has not been used at all. For
+        part of the subject when subpattern n has not been  used  at  all.  For
         example, if the string "abc" is matched against the pattern (a|(z))(bc)
-        subpatterns  1 and 3 are matched, but 2 is not. When this happens, both
+        subpatterns 1 and 3 are matched, but 2 is not. When this happens,  both
         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 is returned.
-        If  the vector is too small to hold all the captured substring offsets,
+        If the vector is too small to hold all the captured substring  offsets,
         it is used as far as possible (up to two-thirds of its length), and the
-        function  returns a value of zero. In particular, if the substring off-
+        function returns a value of zero. In particular, if the substring  off-
         sets are not of interest, pcre_exec() may be called with ovector passed
-        as  NULL  and  ovecsize  as zero. However, if the pattern contains back
+        as NULL and ovecsize as zero. However, if  the  pattern  contains  back
-        references and the ovector is not big enough to  remember  the  related
+        references  and  the  ovector is not big enough to remember the related
-        substrings,  PCRE has to get additional memory for use during matching.
+        substrings, PCRE has to get additional memory for use during  matching.
         Thus it is usually advisable to supply an ovector.
-        Note that pcre_info() can be used to find out how many  capturing  sub-
+        Note  that  pcre_info() can be used to find out how many capturing sub-
         patterns there are in a compiled pattern. The smallest size for ovector
-        that will allow for n captured substrings, in addition to  the  offsets
+        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
+        If pcre_exec() fails, it returns a negative number. The  following  are
         defined in the header file:
           PCRE_ERROR_NOMATCH        (-1)
-Line 1676 
 MATCHING A PATTERN: THE TRADITIONAL FUNC
+Line 1705 
 MATCHING A PATTERN: THE TRADITIONAL FUNC
           PCRE_ERROR_NULL           (-2)
-        Either code or subject was passed as NULL,  or  ovector  was  NULL  and
+        Either  code  or  subject  was  passed as NULL, or ovector was NULL and
         ovecsize was not zero.
           PCRE_ERROR_BADOPTION      (-3)
-Line 1685 
 MATCHING A PATTERN: THE TRADITIONAL FUNC
+Line 1714 
 MATCHING A PATTERN: THE TRADITIONAL FUNC
           PCRE_ERROR_BADMAGIC       (-4)
-        PCRE  stores a 4-byte "magic number" at the start of the compiled code,
+        PCRE stores a 4-byte "magic number" at the start of the compiled  code,
         to catch the case when it is passed a junk pointer and to detect when a
         pattern that was compiled in an environment of one endianness is run in
-        an environment with the other endianness. This is the error  that  PCRE
+        an  environment  with the other endianness. This is the error that PCRE
         gives when the magic number is not present.
           PCRE_ERROR_UNKNOWN_NODE   (-5)
         While running the pattern match, an unknown item was encountered in the
-        compiled pattern. This error could be caused by a bug  in  PCRE  or  by
+        compiled  pattern.  This  error  could be caused by a bug in PCRE or by
         overwriting of the compiled pattern.
           PCRE_ERROR_NOMEMORY       (-6)
-        If  a  pattern contains back references, but the ovector that is passed
+        If a pattern contains back references, but the ovector that  is  passed
         to pcre_exec() is not big enough to remember the referenced substrings,
-        PCRE  gets  a  block of memory at the start of matching to use for this
+        PCRE gets a block of memory at the start of matching to  use  for  this
-        purpose. If the call via pcre_malloc() fails, this error is given.  The
+        purpose.  If the call via pcre_malloc() fails, this error is given. The
         memory is automatically freed at the end of matching.
           PCRE_ERROR_NOSUBSTRING    (-7)
-        This  error is used by the pcre_copy_substring(), pcre_get_substring(),
+        This error is used by the pcre_copy_substring(),  pcre_get_substring(),
         and  pcre_get_substring_list()  functions  (see  below).  It  is  never
         returned by pcre_exec().
           PCRE_ERROR_MATCHLIMIT     (-8)
-        The  recursion  and backtracking limit, as specified by the match_limit
+        The backtracking limit, as specified by  the  match_limit  field  in  a
-        field in a pcre_extra structure (or defaulted)  was  reached.  See  the
+        pcre_extra  structure  (or  defaulted) was reached. See the description
+        above.
+          PCRE_ERROR_RECURSIONLIMIT (-21)
+        The internal recursion limit, as specified by the match_limit_recursion
+        field  in  a  pcre_extra  structure (or defaulted) was reached. See the
         description above.
           PCRE_ERROR_CALLOUT        (-9)
         This error is never generated by pcre_exec() itself. It is provided for
-        use by callout functions that want to yield a distinctive  error  code.
+        use  by  callout functions that want to yield a distinctive error code.
         See the pcrecallout documentation for details.
           PCRE_ERROR_BADUTF8        (-10)
-        A  string  that contains an invalid UTF-8 byte sequence was passed as a
+        A string that contains an invalid UTF-8 byte sequence was passed  as  a
         subject.
           PCRE_ERROR_BADUTF8_OFFSET (-11)
         The UTF-8 byte sequence that was passed as a subject was valid, but the
-        value  of startoffset did not point to the beginning of a UTF-8 charac-
+        value of startoffset did not point to the beginning of a UTF-8  charac-
         ter.
           PCRE_ERROR_PARTIAL        (-12)
-        The subject string did not match, but it did match partially.  See  the
+        The  subject  string did not match, but it did match partially. See the
         pcrepartial documentation for details of partial matching.
           PCRE_ERROR_BADPARTIAL     (-13)
-        The  PCRE_PARTIAL  option  was  used with a compiled pattern containing
+        The PCRE_PARTIAL option was used with  a  compiled  pattern  containing
-        items that are not supported for partial matching. See the  pcrepartial
+        items  that are not supported for partial matching. See the pcrepartial
         documentation for details of partial matching.
           PCRE_ERROR_INTERNAL       (-14)
-        An  unexpected  internal error has occurred. This error could be caused
+        An unexpected internal error has occurred. This error could  be  caused
         by a bug in PCRE or by overwriting of the compiled pattern.
           PCRE_ERROR_BADCOUNT       (-15)
-        This error is given if the value of the ovecsize argument is  negative.
+        This  error is given if the value of the ovecsize argument is negative.
  EXTRACTING CAPTURED SUBSTRINGS BY NUMBER
-Line 1768 
 EXTRACTING CAPTURED SUBSTRINGS BY NUMBER
+Line 1803 
 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 that has  just  been  successfully
+        tions:  subject  is  the subject string that has just been successfully
         matched, ovector is a pointer to the vector of integer offsets that was
         passed to pcre_exec(), and stringcount is the number of substrings that
-        were  captured  by  the match, including the substring that matched the
+        were captured by the match, including the substring  that  matched  the
         entire regular expression. This is the value returned by pcre_exec() if
-        it  is greater than zero. If pcre_exec() returned zero, indicating that
+        it is greater than zero. If pcre_exec() returned zero, indicating  that
-        it ran out of space in ovector, the value passed as stringcount  should
+        it  ran out of space in ovector, the value passed as stringcount should
         be the number of elements in the vector divided by three.
-        The  functions pcre_copy_substring() and pcre_get_substring() extract a
+        The functions pcre_copy_substring() and pcre_get_substring() extract  a
-        single substring, whose number is given as  stringnumber.  A  value  of
+        single  substring,  whose  number  is given as stringnumber. A value of
-        zero  extracts  the  substring that matched the entire pattern, whereas
+        zero extracts the substring that matched the  entire  pattern,  whereas
-        higher values  extract  the  captured  substrings.  For  pcre_copy_sub-
+        higher  values  extract  the  captured  substrings.  For pcre_copy_sub-
-        string(),  the  string  is  placed  in buffer, whose length is given by
+        string(), the string is placed in buffer,  whose  length  is  given  by
-        buffersize, while for pcre_get_substring() a new  block  of  memory  is
+        buffersize,  while  for  pcre_get_substring()  a new block of memory is
-        obtained  via  pcre_malloc,  and its address is returned via stringptr.
+        obtained via pcre_malloc, and its address is  returned  via  stringptr.
-        The yield of the function is the length of the  string,  not  including
+        The  yield  of  the function is the length of the string, not including
         the terminating zero, or one of
           PCRE_ERROR_NOMEMORY       (-6)
-        The  buffer  was too small for pcre_copy_substring(), or the attempt to
+        The buffer was too small for pcre_copy_substring(), or the  attempt  to
         get memory failed for pcre_get_substring().
           PCRE_ERROR_NOSUBSTRING    (-7)
         There is no substring whose number is stringnumber.
-        The pcre_get_substring_list()  function  extracts  all  available  sub-
+        The  pcre_get_substring_list()  function  extracts  all  available sub-
-        strings  and  builds  a list of pointers to them. All this is done in a
+        strings and builds a list of pointers to them. All this is  done  in  a
         single block of memory that is obtained via pcre_malloc. The address of
-        the  memory  block  is returned via listptr, which is also the start of
+        the memory block is returned via listptr, which is also  the  start  of
-        the list of string pointers. The end of the list is marked  by  a  NULL
+        the  list  of  string pointers. The end of the list is marked by a NULL
         pointer. The yield of the function is zero if all went well, or
           PCRE_ERROR_NOMEMORY       (-6)
         if the attempt to get the memory block failed.
-        When  any of these functions encounter a substring that is unset, which
+        When any of these functions encounter a substring that is unset,  which
-        can happen when capturing subpattern number n+1 matches  some  part  of
+        can  happen  when  capturing subpattern number n+1 matches some part of
-        the  subject, but subpattern n has not been used at all, they return an
+        the subject, but subpattern n has not been used at all, they return  an
         empty string. This can be distinguished from a genuine zero-length sub-
-        string  by inspecting the appropriate offset in ovector, which is nega-
+        string by inspecting the appropriate offset in ovector, which is  nega-
         tive for unset substrings.
-        The two convenience functions pcre_free_substring() and  pcre_free_sub-
+        The  two convenience functions pcre_free_substring() and pcre_free_sub-
-        string_list()  can  be  used  to free the memory returned by a previous
+        string_list() can be used to free the memory  returned  by  a  previous
         call  of  pcre_get_substring()  or  pcre_get_substring_list(),  respec-
-        tively.  They  do  nothing  more  than  call the function pointed to by
+        tively. They do nothing more than  call  the  function  pointed  to  by
-        pcre_free, which of course could be called directly from a  C  program.
+        pcre_free,  which  of course could be called directly from a C program.
-        However,  PCRE is used in some situations where it is linked via a spe-
+        However, PCRE is used in some situations where it is linked via a  spe-
         cial  interface  to  another  programming  language  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  pro-
         vided.
-Line 1851 
 EXTRACTING CAPTURED SUBSTRINGS BY NAME
+Line 1886 
 EXTRACTING CAPTURED SUBSTRINGS BY NAME
              int stringcount, const char *stringname,
              const char **stringptr);
-        To extract a substring by name, you first have to find associated  num-
+        To  extract a substring by name, you first have to find associated num-
         ber.  For example, for this pattern
           (a+)b(?P<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  compiled  pattern,  and  the  second is the name. The yield of the
+        the compiled pattern, and the second is the  name.  The  yield  of  the
-        function is the subpattern number, or  PCRE_ERROR_NOSUBSTRING  (-7)  if
+        function  is  the  subpattern number, or PCRE_ERROR_NOSUBSTRING (-7) if
         there is no subpattern of that name.
         Given the number, you can extract the substring directly, or use one of
         the functions described in the previous section. For convenience, there
         are also two functions that do the whole job.
-        Most    of    the    arguments   of   pcre_copy_named_substring()   and
+        Most   of   the   arguments    of    pcre_copy_named_substring()    and
-        pcre_get_named_substring() are the same  as  those  for  the  similarly
+        pcre_get_named_substring()  are  the  same  as  those for the similarly
-        named  functions  that extract by number. As these are described in the
+        named functions that extract by number. As these are described  in  the
-        previous section, they are not re-described here. There  are  just  two
+        previous  section,  they  are not re-described here. There are just two
         differences:
-        First,  instead  of a substring number, a substring name is given. Sec-
+        First, instead of a substring number, a substring name is  given.  Sec-
         ond, there is an extra argument, given at the start, which is a pointer
-        to  the compiled pattern. This is needed in order to gain access to the
+        to the compiled pattern. This is needed in order to gain access to  the
         name-to-number translation table.
-        These functions call pcre_get_stringnumber(), and if it succeeds,  they
+        These  functions call pcre_get_stringnumber(), and if it succeeds, they
-        then  call  pcre_copy_substring() or pcre_get_substring(), as appropri-
+        then call pcre_copy_substring() or pcre_get_substring(),  as  appropri-
         ate.
  FINDING ALL POSSIBLE MATCHES
-        The traditional matching function uses a  similar  algorithm  to  Perl,
+        The  traditional  matching  function  uses a similar algorithm to Perl,
         which stops when it finds the first match, starting at a given point in
-        the subject. If you want to find all possible matches, or  the  longest
+        the  subject.  If you want to find all possible matches, or the longest
-        possible  match,  consider using the alternative matching function (see
+        possible match, consider using the alternative matching  function  (see
-        below) instead. If you cannot use the alternative function,  but  still
+        below)  instead.  If you cannot use the alternative function, but still
-        need  to  find all possible matches, you can kludge it up by making use
+        need to find all possible matches, you can kludge it up by  making  use
         of the callout facility, which is described in the pcrecallout documen-
         tation.
         What you have to do is to insert a callout right at the end of the pat-
-        tern.  When your callout function is called, extract and save the  cur-
+        tern.   When your callout function is called, extract and save the cur-
-        rent  matched  substring.  Then  return  1, which forces pcre_exec() to
+        rent matched substring. Then return  1,  which  forces  pcre_exec()  to
-        backtrack and try other alternatives. Ultimately, when it runs  out  of
+        backtrack  and  try other alternatives. Ultimately, when it runs out of
         matches, pcre_exec() will yield PCRE_ERROR_NOMATCH.
-Line 1907 
 MATCHING A PATTERN: THE ALTERNATIVE FUNC
+Line 1942 
 MATCHING A PATTERN: THE ALTERNATIVE FUNC
              int options, int *ovector, int ovecsize,
              int *workspace, int wscount);
-        The  function  pcre_dfa_exec()  is  called  to  match  a subject string
+        The function pcre_dfa_exec()  is  called  to  match  a  subject  string
-        against a compiled pattern, using a "DFA" matching algorithm. This  has
+        against  a compiled pattern, using a "DFA" matching algorithm. This has
-        different  characteristics to the normal algorithm, and is not compati-
+        different characteristics to the normal algorithm, and is not  compati-
         ble with Perl. Some of the features of PCRE patterns are not supported.
         Nevertheless, there are times when this kind of matching can be useful.
-        For a discussion of the two matching algorithms, see  the  pcrematching
+        For  a  discussion of the two matching algorithms, see the pcrematching
         documentation.
-        The  arguments  for  the  pcre_dfa_exec()  function are the same as for
+        The arguments for the pcre_dfa_exec() function  are  the  same  as  for
         pcre_exec(), plus two extras. The ovector argument is used in a differ-
-        ent  way,  and  this is described below. The other common arguments are
+        ent way, and this is described below. The other  common  arguments  are
-        used in the same way as for pcre_exec(), so their  description  is  not
+        used  in  the  same way as for pcre_exec(), so their description is not
         repeated here.
-        The  two  additional  arguments provide workspace for the function. The
+        The two additional arguments provide workspace for  the  function.  The
-        workspace vector should contain at least 20 elements. It  is  used  for
+        workspace  vector  should  contain at least 20 elements. It is used for
         keeping  track  of  multiple  paths  through  the  pattern  tree.  More
-        workspace will be needed for patterns and subjects where  there  are  a
+        workspace  will  be  needed for patterns and subjects where there are a
         lot of possible matches.
-        Here is an example of a simple call to pcre_exec():
+        Here is an example of a simple call to pcre_dfa_exec():
           int rc;
           int ovector[10];
           int wspace[20];
-          rc = pcre_exec(
+          rc = pcre_dfa_exec(
             re,             /* result of pcre_compile() */
             NULL,           /* we didn't study the pattern */
             "some string",  /* the subject string */
-Line 1946 
 MATCHING A PATTERN: THE ALTERNATIVE FUNC
+Line 1981 
 MATCHING A PATTERN: THE ALTERNATIVE FUNC
     Option bits for pcre_dfa_exec()
-        The  unused  bits  of  the options argument for pcre_dfa_exec() must be
+        The unused bits of the options argument  for  pcre_dfa_exec()  must  be
-        zero. The only bits that may be  set  are  PCRE_ANCHORED,  PCRE_NOTBOL,
+        zero.  The  only  bits  that may be set are PCRE_ANCHORED, PCRE_NOTBOL,
-        PCRE_NOTEOL,     PCRE_NOTEMPTY,    PCRE_NO_UTF8_CHECK,    PCRE_PARTIAL,
+        PCRE_NOTEOL,    PCRE_NOTEMPTY,    PCRE_NO_UTF8_CHECK,     PCRE_PARTIAL,
-        PCRE_DFA_SHORTEST, and PCRE_DFA_RESTART. All  but  the  last  three  of
+        PCRE_DFA_SHORTEST,  and  PCRE_DFA_RESTART.  All  but  the last three of
-        these  are  the  same  as  for pcre_exec(), so their description is not
+        these are the same as for pcre_exec(),  so  their  description  is  not
         repeated here.
           PCRE_PARTIAL
-        This has the same general effect as it does for  pcre_exec(),  but  the
+        This  has  the  same general effect as it does for pcre_exec(), but the
-        details   are   slightly   different.  When  PCRE_PARTIAL  is  set  for
+        details  are  slightly  different.  When  PCRE_PARTIAL   is   set   for
-        pcre_dfa_exec(), the return code PCRE_ERROR_NOMATCH is  converted  into
+        pcre_dfa_exec(),  the  return code PCRE_ERROR_NOMATCH is converted into
-        PCRE_ERROR_PARTIAL  if  the  end  of the subject is reached, there have
+        PCRE_ERROR_PARTIAL if the end of the subject  is  reached,  there  have
         been no complete matches, but there is still at least one matching pos-
-        sibility.  The portion of the string that provided the partial match is
+        sibility. The portion of the string that provided the partial match  is
         set as the first matching string.
           PCRE_DFA_SHORTEST
-        Setting the PCRE_DFA_SHORTEST option causes the matching  algorithm  to
+        Setting  the  PCRE_DFA_SHORTEST option causes the matching algorithm to
-        stop  as  soon  as  it  has found one match. Because of the way the DFA
+        stop as soon as it has found one match. Because  of  the  way  the  DFA
         algorithm works, this is necessarily the shortest possible match at the
         first possible matching point in the subject string.
           PCRE_DFA_RESTART
-        When  pcre_dfa_exec()  is  called  with  the  PCRE_PARTIAL  option, and
+        When pcre_dfa_exec()  is  called  with  the  PCRE_PARTIAL  option,  and
-        returns a partial match, it is possible to call it  again,  with  addi-
+        returns  a  partial  match, it is possible to call it again, with addi-
-        tional  subject  characters,  and have it continue with the same match.
+        tional subject characters, and have it continue with  the  same  match.
-        The PCRE_DFA_RESTART option requests this action; when it is  set,  the
+        The  PCRE_DFA_RESTART  option requests this action; when it is set, the
-        workspace  and wscount options must reference the same vector as before
+        workspace and wscount options must reference the same vector as  before
-        because data about the match so far is left in  them  after  a  partial
+        because  data  about  the  match so far is left in them after a partial
-        match.  There  is  more  discussion of this facility in the pcrepartial
+        match. There is more discussion of this  facility  in  the  pcrepartial
         documentation.
     Successful returns from pcre_dfa_exec()
-        When pcre_dfa_exec() succeeds, it may have matched more than  one  sub-
+        When  pcre_dfa_exec()  succeeds, it may have matched more than one sub-
         string in the subject. Note, however, that all the matches from one run
-        of the function start at the same point in  the  subject.  The  shorter
+        of  the  function  start  at the same point in the subject. The shorter
-        matches  are all initial substrings of the longer matches. For example,
+        matches are all initial substrings of the longer matches. For  example,
         if the pattern
           <.*>
-Line 2001 
 MATCHING A PATTERN: THE ALTERNATIVE FUNC
+Line 2036 
 MATCHING A PATTERN: THE ALTERNATIVE FUNC
           <something> <something else>
           <something> <something else> <something further>
-        On success, the yield of the function is a number  greater  than  zero,
+        On  success,  the  yield of the function is a number greater than zero,
-        which  is  the  number of matched substrings. The substrings themselves
+        which is the number of matched substrings.  The  substrings  themselves
-        are returned in ovector. Each string uses two elements;  the  first  is
+        are  returned  in  ovector. Each string uses two elements; the first is
-        the  offset  to the start, and the second is the offset to the end. All
+        the offset to the start, and the second is the offset to the  end.  All
         the strings have the same start offset. (Space could have been saved by
-        giving  this only once, but it was decided to retain some compatibility
+        giving this only once, but it was decided to retain some  compatibility
-        with the way pcre_exec() returns data, even though the meaning  of  the
+        with  the  way pcre_exec() returns data, even though the meaning of the
         strings is different.)
         The strings are returned in reverse order of length; that is, the long-
-        est matching string is given first. If there were too many  matches  to
+        est  matching  string is given first. If there were too many matches to
-        fit  into ovector, the yield of the function is zero, and the vector is
+        fit into ovector, the yield of the function is zero, and the vector  is
         filled with the longest matches.
     Error returns from pcre_dfa_exec()
-        The pcre_dfa_exec() function returns a negative number when  it  fails.
+        The  pcre_dfa_exec()  function returns a negative number when it fails.
-        Many  of  the  errors  are  the  same as for pcre_exec(), and these are
+        Many of the errors are the same  as  for  pcre_exec(),  and  these  are
-        described above.  There are in addition the following errors  that  are
+        described  above.   There are in addition the following errors that are
         specific to pcre_dfa_exec():
           PCRE_ERROR_DFA_UITEM      (-16)
-        This  return is given if pcre_dfa_exec() encounters an item in the pat-
+        This return is given if pcre_dfa_exec() encounters an item in the  pat-
-        tern that it does not support, for instance, the use of \C  or  a  back
+        tern  that  it  does not support, for instance, the use of \C or a back
         reference.
           PCRE_ERROR_DFA_UCOND      (-17)
-        This  return is given if pcre_dfa_exec() encounters a condition item in
+        This return is given if pcre_dfa_exec() encounters a condition item  in
-        a pattern that uses a back reference for the  condition.  This  is  not
+        a  pattern  that  uses  a back reference for the condition. This is not
         supported.
           PCRE_ERROR_DFA_UMLIMIT    (-18)
-        This  return  is given if pcre_dfa_exec() is called with an extra block
+        This return is given if pcre_dfa_exec() is called with an  extra  block
         that contains a setting of the match_limit field. This is not supported
         (it is meaningless).
           PCRE_ERROR_DFA_WSSIZE     (-19)
-        This  return  is  given  if  pcre_dfa_exec()  runs  out of space in the
+        This return is given if  pcre_dfa_exec()  runs  out  of  space  in  the
         workspace vector.
           PCRE_ERROR_DFA_RECURSE    (-20)
-        When a recursive subpattern is processed, the matching  function  calls
+        When  a  recursive subpattern is processed, the matching function calls
-        itself  recursively,  using  private vectors for ovector and workspace.
+        itself recursively, using private vectors for  ovector  and  workspace.
-        This error is given if the output vector  is  not  large  enough.  This
+        This  error  is  given  if  the output vector is not large enough. This
         should be extremely rare, as a vector of size 1000 is used.
- Last updated: 16 May 2005
+ Last updated: 18 January 2006
- Copyright (c) 1997-2005 University of Cambridge.
+ Copyright (c) 1997-2006 University of Cambridge.
  ------------------------------------------------------------------------------
-Line 2229 
 DIFFERENCES BETWEEN PCRE AND PERL
+Line 2264 
 DIFFERENCES BETWEEN PCRE AND PERL
         handle regular expressions. The differences  described  here  are  with
         respect to Perl 5.8.
-.  PCRE does not have full UTF-8 support. Details of what it does have
+.  PCRE has only a subset of Perl's UTF-8 and Unicode support. Details
-        are given in the section on UTF-8 support in the main pcre page.
+        of what it does have are given in the section on UTF-8 support  in  the
+        main pcre page.
 . PCRE does not allow repeat quantifiers on lookahead assertions. Perl
-        permits  them,  but they do not mean what you might think. For example,
+        permits them, but they do not mean what you might think.  For  example,
         (?!a){3} does not assert that the next three characters are not "a". It
         just asserts that the next character is not "a" three times.
-.  Capturing  subpatterns  that occur inside negative lookahead asser-
+. Capturing subpatterns that occur inside  negative  lookahead  asser-
-        tions are counted, but their entries in the offsets  vector  are  never
+        tions  are  counted,  but their entries in the offsets vector are never
-        set.  Perl sets its numerical variables from any such patterns that are
+        set. Perl sets its numerical variables from any such patterns that  are
         matched before the assertion fails to match something (thereby succeed-
-        ing),  but  only  if the negative lookahead assertion contains just one
+        ing), but only if the negative lookahead assertion  contains  just  one
         branch.
-. Though binary zero characters are supported in the  subject  string,
+.  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 in
         the pattern to represent a binary zero.
-.  The  following Perl escape sequences are not supported: \l, \u, \L,
+. The following Perl escape sequences are not supported: \l,  \u,  \L,
         \U, and \N. In fact these are implemented by Perl's general string-han-
-        dling  and are not part of its pattern matching engine. If any of these
+        dling and are not part of its pattern matching engine. If any of  these
         are encountered by PCRE, an error is generated.
-. The Perl escape sequences \p, \P, and \X are supported only if  PCRE
+.  The Perl escape sequences \p, \P, and \X are supported only if PCRE
-        is  built  with Unicode character property support. The properties that
+        is built with Unicode character property support. The  properties  that
-        can be tested with \p and \P are limited to the general category  prop-
+        can  be tested with \p and \P are limited to the general category prop-
-        erties such as Lu and Nd.
+        erties such as Lu and Nd, script names such as Greek or  Han,  and  the
+        derived properties Any and L&.
 . PCRE does support the \Q...\E escape for quoting substrings. Charac-
         ters in between are treated as literals.  This  is  slightly  different
-Line 2330 
 DIFFERENCES BETWEEN PCRE AND PERL
+Line 2367 
 DIFFERENCES BETWEEN PCRE AND PERL
         (n)  The  alternative  matching function (pcre_dfa_exec()) matches in a
         different way and is not Perl-compatible.
- Last updated: 28 February 2005
+ Last updated: 24 January 2006
- Copyright (c) 1997-2005 University of Cambridge.
+ Copyright (c) 1997-2006 University of Cambridge.
  ------------------------------------------------------------------------------
-Line 2477 
 BACKSLASH
+Line 2514 
 BACKSLASH
           \t        tab (hex 09)
           \ddd      character with octal code ddd, or backreference
           \xhh      character with hex code hh
-          \x{hhh..} character with hex code hhh... (UTF-8 mode only)
+          \x{hhh..} character with hex code hhh..
         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
-Line 2485 
 BACKSLASH
+Line 2522 
 BACKSLASH
         becomes hex 7B.
         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). Any number of hexadecimal digits may appear
-        its may appear between \x{ and }, but the value of the  character  code
+        between \x{ and }, but the value of the character  code  must  be  less
-        must  be  less  than  2**31  (that is, the maximum hexadecimal value is
+        than 256 in non-UTF-8 mode, and less than 2**31 in UTF-8 mode (that is,
-FFFFFFF). If characters other than hexadecimal digits  appear  between
+        the maximum hexadecimal value is 7FFFFFFF). If  characters  other  than
-        \x{  and }, or if there is no terminating }, this form of escape is not
+        hexadecimal  digits  appear between \x{ and }, or if there is no termi-
-        recognized. Instead, the initial \x will  be  interpreted  as  a  basic
+        nating }, this form of escape is not recognized.  Instead, the  initial
-        hexadecimal  escape, with no following digits, giving a character whose
+        \x will be interpreted as a basic hexadecimal escape, with no following
-        value is zero.
+        digits, giving a character whose value is zero.
         Characters whose value is less than 256 can be defined by either of the
-        two  syntaxes for \x when PCRE is in UTF-8 mode. There is no difference
+        two  syntaxes  for  \x. There is no difference in the way they are han-
-        in the way they are handled. For example, \xdc is exactly the  same  as
+        dled. For example, \xdc is exactly the same as \x{dc}.
-        \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 pattern character that follows is itself  an  octal
-        initial  zero  if the pattern character that follows is itself an octal
         digit.
         The handling of a backslash followed by a digit other than 0 is compli-
         cated.  Outside a character class, PCRE reads it and any following dig-
-        its as a decimal number. If the number is less than  10,  or  if  there
+        its  as  a  decimal  number. If the number is less than 10, or if there
         have been at least that many previous capturing left parentheses in the
-        expression, the entire  sequence  is  taken  as  a  back  reference.  A
+        expression,  the  entire  sequence  is  taken  as  a  back reference. A
-        description  of how this works is given later, following the discussion
+        description of how this works is given later, following the  discussion
         of parenthesized subpatterns.
-        Inside a character class, or if the decimal number is  greater  than  9
+        Inside  a  character  class, or if the decimal number is greater than 9
-        and  there have not been that many capturing subpatterns, PCRE re-reads
+        and there have not been that many capturing subpatterns, PCRE  re-reads
-        up to three octal digits following the backslash, and generates a  sin-
+        up  to three octal digits following the backslash, and generates a sin-
         gle byte from the least significant 8 bits of the value. Any subsequent
         digits stand for themselves.  For example:
-Line 2535 
 BACKSLASH
+Line 2571 
 BACKSLASH
           \81    is either a back reference, or a binary zero
                     followed by the two characters "8" and "1"
-        Note that octal values of 100 or greater must not be  introduced  by  a
+        Note  that  octal  values of 100 or greater must not be introduced by a
         leading zero, because no more than three octal digits are ever read.
-        All  the  sequences  that  define a single byte value or a single UTF-8
+        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
+        classes. In addition, inside a character  class,  the  sequence  \b  is
         interpreted as the backspace character (hex 08), and the sequence \X is
-        interpreted  as  the  character  "X".  Outside a character class, these
+        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
-Line 2558 
 BACKSLASH
+Line 2594 
 BACKSLASH
           \W     any "non-word" character
         Each pair of escape sequences partitions the complete set of characters
-        into two disjoint sets. Any given character matches one, and only  one,
+        into  two disjoint sets. Any given character matches one, and only one,
         of each pair.
         These character type sequences can appear both inside and outside char-
-        acter classes. They each match one character of the  appropriate  type.
+        acter  classes.  They each match one character of the appropriate type.
-        If  the current matching point is at the end of the subject string, all
+        If the current matching point is at the end of the subject string,  all
         of them fail, since there is no character to match.
-        For compatibility with Perl, \s does not match the VT  character  (code
+        For  compatibility  with Perl, \s does not match the VT character (code
-).   This makes it different from the the POSIX "space" class. The \s
+).  This makes it different from the the POSIX "space" class. The  \s
         characters are HT (9), LF (10), FF (12), CR (13), and space (32).
         A "word" character is an underscore or any character less than 256 that
-        is  a  letter  or  digit.  The definition of letters and digits is con-
+        is a letter or digit. The definition of  letters  and  digits  is  con-
-        trolled by PCRE's low-valued character tables, and may vary if  locale-
+        trolled  by PCRE's low-valued character tables, and may vary if locale-
-        specific  matching is taking place (see "Locale support" in the pcreapi
+        specific matching is taking place (see "Locale support" in the  pcreapi
-        page). For example, in the  "fr_FR"  (French)  locale,  some  character
+        page).  For  example,  in  the  "fr_FR" (French) locale, some character
-        codes  greater  than  128  are used for accented letters, and these are
+        codes greater than 128 are used for accented  letters,  and  these  are
         matched by \w.
-        In UTF-8 mode, characters with values greater than 128 never match  \d,
+        In  UTF-8 mode, characters with values greater than 128 never match \d,
         \s, or \w, and always match \D, \S, and \W. This is true even when Uni-
-        code character property support is available.
+        code  character  property support is available. The use of locales with
+        Unicode is discouraged.
     Unicode character properties
         When PCRE is built with Unicode character property support, three addi-
-        tional  escape sequences to match generic character types are available
+        tional  escape  sequences  to  match character properties are available
         when UTF-8 mode is selected. They are:
-         \p{xx}   a character with the xx property
+          \p{xx}   a character with the xx property
-         \P{xx}   a character without the xx property
+          \P{xx}   a character without the xx property
-         \X       an extended Unicode sequence
+          \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-
+        script names, the general category properties, and "Any", which matches
-        erty, specified by a two-letter abbreviation.  For  compatibility  with
+        any character (including newline). Other properties such as "InMusical-
-        Perl,  negation  can be specified by including a circumflex between the
+        Symbols"  are  not  currently supported by PCRE. Note that \P{Any} does
-        opening brace and the property name. For example, \p{^Lu} is  the  same
+        not match any characters, so always causes a match failure.
-        as \P{Lu}.
+        Sets of Unicode characters are defined as belonging to certain scripts.
-        If  only  one  letter  is  specified with \p or \P, it includes all the
+        A  character from one of these sets can be matched using a script name.
-        properties that start with that letter. In this case, in the absence of
+        For example:
-        negation, the curly brackets in the escape sequence are optional; these
-        two examples have the same effect:
+          \p{Greek}
+          \P{Han}
+        Those that are not part of an identified script are lumped together  as
+        "Common". The current list of scripts is:
+        Arabic,  Armenian,  Bengali,  Bopomofo, Braille, Buginese, Buhid, Cana-
+        dian_Aboriginal, Cherokee, Common, Coptic, Cypriot, Cyrillic,  Deseret,
+        Devanagari,  Ethiopic,  Georgian,  Glagolitic, Gothic, Greek, Gujarati,
+        Gurmukhi, Han, Hangul, Hanunoo, Hebrew, Hiragana,  Inherited,  Kannada,
+        Katakana,  Kharoshthi,  Khmer,  Lao, Latin, Limbu, Linear_B, Malayalam,
+        Mongolian, Myanmar, New_Tai_Lue, Ogham, Old_Italic, Old_Persian, Oriya,
+        Osmanya,  Runic,  Shavian, Sinhala, Syloti_Nagri, Syriac, Tagalog, Tag-
+        banwa,  Tai_Le,  Tamil,  Telugu,  Thaana,  Thai,   Tibetan,   Tifinagh,
+        Ugaritic, Yi.
+        Each  character has exactly one general category property, specified by
+        a two-letter abbreviation. For compatibility with Perl, negation can be
+        specified  by  including a circumflex between the opening brace and the
+        property name. For example, \p{^Lu} is the same as \P{Lu}.
+        If only one letter is specified with \p or \P, it includes all the gen-
+        eral  category properties that start with that letter. In this case, in
+        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:
+        The following general category property codes are supported:
           C     Other
           Cc    Control
-Line 2653 
 BACKSLASH
+Line 2714 
 BACKSLASH
           Zp    Paragraph separator
           Zs    Space separator
-        Extended properties such as "Greek" or "InMusicalSymbols" are not  sup-
+        The  special property L& is also supported: it matches a character that
-        ported by PCRE.
+        has the Lu, Ll, or Lt property, in other words, a letter  that  is  not
+        classified as a modifier or "other".
+        The  long  synonyms  for  these  properties that Perl supports (such as
+        \p{Letter}) are not supported by PCRE. Nor is is  permitted  to  prefix
+        any of these properties with "Is".
+        No character that is in the Unicode table has the Cn (unassigned) prop-
+        erty.  Instead, this property is assumed for any code point that is not
+        in the Unicode table.
         Specifying  caseless  matching  does not affect these escape sequences.
         For example, \p{Lu} always matches only upper case letters.
-Line 3633 
 RECURSIVE PATTERNS
+Line 3703 
 RECURSIVE PATTERNS
         tion.)  The special item (?R) is a recursive call of the entire regular
         expression.
-        For example, this PCRE pattern solves the  nested  parentheses  problem
+        A recursive subpattern call is always treated as an atomic group.  That
-        (assume  the  PCRE_EXTENDED  option  is  set  so  that  white  space is
+        is,  once  it  has  matched some of the subject string, it is never re-
-        ignored):
+        entered, even if it contains untried alternatives and there is a subse-
+        quent matching failure.
+        This  PCRE  pattern  solves  the nested parentheses problem (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
         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
-Line 3725 
 SUBPATTERNS AS SUBROUTINES
+Line 3799 
 SUBPATTERNS AS SUBROUTINES
         two strings. Such references must, however, follow  the  subpattern  to
         which they refer.
+        Like recursive subpatterns, a "subroutine" call is always treated as an
+        atomic group. That is, once it has matched some of the subject  string,
+        it  is  never  re-entered, even if it contains untried alternatives and
+        there is a subsequent matching failure.
  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
+        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, the position in the pattern, and, optionally, one item
+        of the callout, the position in the pattern, and, optionally, one  item
-        of data originally supplied by the caller of pcre_exec().  The  callout
+        of  data  originally supplied by the caller of pcre_exec(). The callout
-        function  may cause matching to proceed, to backtrack, or to fail alto-
+        function may cause matching to proceed, to backtrack, or to fail  alto-
         gether. A complete description of the interface to the callout function
         is given in the pcrecallout documentation.
- Last updated: 28 February 2005
+ Last updated: 24 January 2006
- Copyright (c) 1997-2005 University of Cambridge.
+ Copyright (c) 1997-2006 University of Cambridge.
  ------------------------------------------------------------------------------
-Line 3851 
 EXAMPLE OF PARTIAL MATCHING USING PCRETE
+Line 3930 
 EXAMPLE OF PARTIAL MATCHING USING PCRETE
         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
+          data> 25jun04\P
 : 25jun04
 : jun
-          data> 25dec3P
+          data> 25dec3\P
           Partial match
-          data> 3juP
+          data> 3ju\P
           Partial match
-          data> 3jujP
+          data> 3juj\P
           No match
-          data> jP
+          data> j\P
           No match
         The first data string is matched  completely,  so  pcretest  shows  the
-Line 3950 
 MULTI-SEGMENT MATCHING WITH pcre_dfa_exe
+Line 4029 
 MULTI-SEGMENT MATCHING WITH pcre_dfa_exe
         Because of this phenomenon, it does not usually make  sense  to  end  a
         pattern that is going to be matched in this way with a variable repeat.
- Last updated: 28 February 2005
+. Patterns that contain alternatives at the top level which do not all
- Copyright (c) 1997-2005 University of Cambridge.
+        start with the same pattern item may not work as expected. For example,
+        consider this pattern:
+|3789
+        If the first part of the subject is "ABC123", a partial  match  of  the
+        first  alternative  is found at offset 3. There is no partial match for
+        the second alternative, because such a match does not start at the same
+        point  in  the  subject  string. Attempting to continue with the string
+        "789" does not yield a match because only those alternatives that match
+        at  one point in the subject are remembered. The problem arises because
+        the start of the second alternative matches within the  first  alterna-
+        tive. There is no problem with anchored patterns or patterns such as:
+|ABCD
+        where no string can be a partial match for both alternatives.
+ Last updated: 16 January 2006
+ Copyright (c) 1997-2006 University of Cambridge.
  ------------------------------------------------------------------------------
-Line 4065 
 COMPATIBILITY WITH DIFFERENT PCRE RELEAS
+Line 4163 
 COMPATIBILITY WITH DIFFERENT PCRE RELEAS
         them for release 5.0. However, from now on, it should  be  possible  to
         make changes in a compatible manner.
- Last updated: 28 February 2005
+        Notwithstanding the above, if you have any saved patterns in UTF-8 mode
- Copyright (c) 1997-2005 University of Cambridge.
+        that use \p or \P that were compiled with any release up to and includ-
+        ing 6.4, you will have to recompile them for release 6.5 and above.
+ Last updated: 01 February 2006
+ Copyright (c) 1997-2006 University of Cambridge.
  ------------------------------------------------------------------------------
-Line 4191 
 DESCRIPTION
+Line 4293 
 DESCRIPTION
         functions call the native ones, it is also necessary to add -lpcre.
         I have implemented only those option bits that can be reasonably mapped
-        to  PCRE  native  options.  In  addition,  the options REG_EXTENDED and
+        to PCRE native options. In addition, the option REG_EXTENDED is defined
-        REG_NOSUB are defined with the value zero. They  have  no  effect,  but
+        with the value zero. This has no effect, but since  programs  that  are
-        since  programs that are written to the POSIX interface often use them,
+        written  to  the  POSIX interface often use it, this makes it easier to
-        this makes it easier to slot in PCRE as a  replacement  library.  Other
+        slot in PCRE as a replacement library. Other POSIX options are not even
-        POSIX options are not even defined.
+        defined.
         When  PCRE  is  called  via these functions, it is only the API that is
         POSIX-like in style. The syntax and semantics of  the  regular  expres-
-Line 4220 
 COMPILING A PATTERN
+Line 4322 
 COMPILING A PATTERN
         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 that is used as a base for storing information  about
-        the compiled expression.
+        the compiled regular expression.
         The argument cflags is either zero, or contains one or more of the bits
         defined by the following macros:
           REG_DOTALL
-        The PCRE_DOTALL option is set when the expression is passed for  compi-
+        The PCRE_DOTALL option is set when the regular expression is passed for
-        lation  to the native function. Note that REG_DOTALL is not part of the
+        compilation to the native function. Note that REG_DOTALL is not part of
-        POSIX standard.
+        the POSIX standard.
           REG_ICASE
-        The PCRE_CASELESS option is set when the expression is passed for  com-
+        The PCRE_CASELESS option is set when the regular expression  is  passed
-        pilation to the native function.
+        for compilation to the native function.
           REG_NEWLINE
-        The PCRE_MULTILINE option is set when the expression is passed for com-
+        The  PCRE_MULTILINE option is set when the regular expression is passed
-        pilation to the native function. Note that  this  does  not  mimic  the
+        for compilation to the native function. Note that this does  not  mimic
-        defined POSIX behaviour for REG_NEWLINE (see the following section).
+        the  defined  POSIX  behaviour  for REG_NEWLINE (see the following sec-
+        tion).
+          REG_NOSUB
+        The PCRE_NO_AUTO_CAPTURE option is set when the regular  expression  is
+        passed for compilation to the native function. In addition, when a pat-
+        tern that is compiled with this flag is passed to regexec() for  match-
+        ing,  the  nmatch  and  pmatch  arguments  are ignored, and no captured
+        strings are returned.
+          REG_UTF8
+        The PCRE_UTF8 option is set when the regular expression is  passed  for
+        compilation  to the native function. This causes the pattern itself and
+        all data strings used for matching it to be treated as  UTF-8  strings.
+        Note that REG_UTF8 is not part of the POSIX standard.
         In  the  absence  of  these  flags, no options are passed to the native
         function.  This means the the  regex  is  compiled  with  PCRE  default
-Line 4307 
 MATCHING A PATTERN
+Line 4425 
 MATCHING A PATTERN
         The PCRE_NOTEOL option is set when calling the underlying PCRE matching
         function.
-        The  portion of the string that was matched, and also any captured sub-
+        If  the pattern was compiled with the REG_NOSUB flag, no data about any
-        strings, are returned via the pmatch argument, which points to an array
+        matched strings  is  returned.  The  nmatch  and  pmatch  arguments  of
-        of  nmatch  structures of type regmatch_t, containing the members rm_so
+        regexec() are ignored.
-        and rm_eo. These contain the offset to the first character of each sub-
-        string and the offset to the first character after the end of each sub-
+        Otherwise,the portion of the string that was matched, and also any cap-
-        string, respectively. The 0th element of  the  vector  relates  to  the
+        tured substrings, are returned via the pmatch argument, which points to
-        entire  portion  of string that was matched; subsequent elements relate
+        an  array  of nmatch structures of type regmatch_t, containing the mem-
-        to the capturing subpatterns of the regular expression. Unused  entries
+        bers rm_so and rm_eo. These contain the offset to the  first  character
-        in the array have both structure members set to -1.
+        of  each  substring and the offset to the first character after the end
+        of each substring, respectively. The 0th element of the vector  relates
+        to  the  entire portion of string that was matched; subsequent elements
+        relate to the capturing subpatterns of the regular  expression.  Unused
+        entries in the array have both structure members set to -1.
         A  successful  match  yields  a  zero  return;  various error codes are
         defined in the header file, of  which  REG_NOMATCH  is  the  "expected"
-Line 4346 
 AUTHOR
+Line 4468 
 AUTHOR
         University Computing Service,
         Cambridge CB2 3QG, England.
- Last updated: 28 February 2005
+ Last updated: 16 January 2006
- Copyright (c) 1997-2005 University of Cambridge.
+ Copyright (c) 1997-2006 University of Cambridge.
  ------------------------------------------------------------------------------
-Line 4520 
 PASSING MODIFIERS TO THE REGULAR EXPRESS
+Line 4642 
 PASSING MODIFIERS TO THE REGULAR EXPRESS
           RE_Options & set_caseless(bool)
-        which sets or unsets the  modifier.  Moreover,  PCRE_CONFIG_MATCH_LIMIT
+        which sets or unsets the modifier. Moreover, PCRE_EXTRA_MATCH_LIMIT can
-        can  be accessed through the set_match_limit() and match_limit() member
+        be  accessed  through  the  set_match_limit()  and match_limit() member
         functions. Setting match_limit to a non-zero value will limit the  exe-
         cution  of pcre to keep it from doing bad things like blowing the stack
         or taking an eternity to return a result.  A  value  of  5000  is  good
         enough  to stop stack blowup in a 2MB thread stack. Setting match_limit
-        to zero disables match limiting.
+        to  zero  disables  match  limiting.  Alternatively,   you   can   call
+        match_limit_recursion()  which uses PCRE_EXTRA_MATCH_LIMIT_RECURSION to
+        limit how much  PCRE  recurses.  match_limit()  limits  the  number  of
+        matches PCRE does; match_limit_recursion() limits the depth of internal
+        recursion, and therefore the amount of stack that is used.
         Normally, to pass one or more modifiers to a RE class,  you  declare  a
         RE_Options object, set the appropriate options, and pass this object to

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