#include <pcrecpp.h>


       The  C++  wrapper  for PCRE was provided by Google Inc. Some additional
       functionality was added by Giuseppe Maxia. This brief man page was con-
       structed  from  the  notes  in the pcrecpp.h file, which should be con-
       sulted for further details. Note that the C++ wrapper supports only the
       original 8-bit PCRE library. There is no 16-bit support at present.


       The  "FullMatch" operation checks that supplied text matches a supplied
       pattern exactly. If pointer arguments are supplied, it  copies  matched
       sub-strings that match sub-patterns into them.

         Example: successful match
            pcrecpp::RE re("h.*o");

         Example: unsuccessful match (requires full match):
            pcrecpp::RE re("e");

         Example: creating a temporary RE object:

       You  can pass in a "const char*" or a "string" for "text". The examples
       below tend to use a const char*. You can, as in the different  examples
       above,  store the RE object explicitly in a variable or use a temporary
       RE object. The examples below use one mode or  the  other  arbitrarily.
       Either could correctly be used for any of these examples.

       You must supply extra pointer arguments to extract matched subpieces.

         Example: extracts "ruby" into "s" and 1234 into "i"
            int i;
            string s;
            pcrecpp::RE re("(\\w+):(\\d+)");
            re.FullMatch("ruby:1234", &s, &i);

         Example: does not try to extract any extra sub-patterns
            re.FullMatch("ruby:1234", &s);

         Example: does not try to extract into NULL
            re.FullMatch("ruby:1234", NULL, &i);

         Example: integer overflow causes failure
            !re.FullMatch("ruby:1234567891234", NULL, &i);

         Example: fails because there aren't enough sub-patterns:

       The function returns true iff all of the following conditions are  sat-

         a. "text" matches "pattern" exactly;

         b. The number of matched sub-patterns is >= number of supplied

         c. The "i"th argument has a suitable type for holding the
            string captured as the "i"th sub-pattern. If you pass in
            void * NULL for the "i"th argument, or a non-void * NULL
            of the correct type, or pass fewer arguments than the
            number of sub-patterns, "i"th captured sub-pattern is

       CAVEAT:  An  optional  sub-pattern  that  does not exist in the matched
       string is assigned the empty  string.  Therefore,  the  following  will
       return false (because the empty string is not a valid number):

          int number;
          pcrecpp::RE::FullMatch("abc", "[a-z]+(\\d+)?", &number);

       The  matching interface supports at most 16 arguments per call.  If you
       need   more,   consider    using    the    more    general    interface
       pcrecpp::RE::DoMatch. See pcrecpp.h for the signature for DoMatch.

       NOTE:  Do not use no_arg, which is used internally to mark the end of a
       list of optional arguments, as a placeholder for missing arguments,  as
       this can lead to segfaults.


       You  can use the "QuoteMeta" operation to insert backslashes before all
       potentially meaningful characters in a  string.  The  returned  string,
       used as a regular expression, will exactly match the original string.

            string quoted = RE::QuoteMeta(unquoted);

       Note  that  it's  legal to escape a character even if it has no special
       meaning in a regular expression -- so this function  does  that.  (This
       also  makes  it  identical  to  the perl function of the same name; see
       "perldoc   -f   quotemeta".)    For   example,    "1.5-2.0?"    becomes


       You  can  use the "PartialMatch" operation when you want the pattern to
       match any substring of the text.

         Example: simple search for a string:

       UTF-8 than the pattern, but the match returned may depend on  the  UTF8
       flag,  so  always use it when matching UTF8 text. For example, "." will
       match one byte normally but with UTF8 set may match up to  three  bytes
       of a multi-byte character.

            pcrecpp::RE_Options options;
            pcrecpp::RE re(utf8_pattern, options);

         Example: using the convenience function UTF8():
            pcrecpp::RE re(utf8_pattern, pcrecpp::UTF8());

       NOTE: The UTF8 flag is ignored if pcre was not configured with the
             --enable-utf8 flag.


       PCRE  defines  some  modifiers  to  change  the behavior of the regular
       expression  engine.  The  C++  wrapper  defines  an  auxiliary   class,
       RE_Options,  as  a  vehicle  to pass such modifiers to a RE class. Cur-
       rently, the following modifiers are supported:

          modifier              description               Perl corresponding

          PCRE_CASELESS         case insensitive match      /i
          PCRE_MULTILINE        multiple lines match        /m
          PCRE_DOTALL           dot matches newlines        /s
          PCRE_DOLLAR_ENDONLY   $ matches only at end       N/A
          PCRE_EXTRA            strict escape parsing       N/A
          PCRE_EXTENDED         ignore white spaces         /x
          PCRE_UTF8             handles UTF8 chars          built-in
          PCRE_UNGREEDY         reverses * and *?           N/A
          PCRE_NO_AUTO_CAPTURE  disables capturing parens   N/A (*)

       (*) Both Perl and PCRE allow non capturing parentheses by means of  the
       "?:"  modifier  within the pattern itself. e.g. (?:ab|cd) does not cap-
       ture, while (ab|cd) does.

       For a full account on how each modifier works, please  check  the  PCRE
       API reference page.

       For  each  modifier,  there are two member functions whose name is made
       out of the modifier in  lowercase,  without  the  "PCRE_"  prefix.  For
       instance, PCRE_CASELESS is handled by

         bool caseless()

       which returns true if the modifier is set, and

         RE_Options & set_caseless(bool)

       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
       a RE constructor. Example:

          RE_Options opt;
          if (RE("HELLO", opt).PartialMatch("hello world")) ...

       RE_options has two constructors. The default constructor takes no argu-
       ments and creates a set of flags that are off by default. The  optional
       parameter  option_flags is to facilitate transfer of legacy code from C
       programs.  This lets you do


       However, new code is better off doing


       If you are going to pass one of the most used modifiers, there are some
       convenience functions that return a RE_Options class with the appropri-
       ate modifier already set: CASELESS(),  UTF8(),  MULTILINE(),  DOTALL(),
       and EXTENDED().

       If  you  need  to set several options at once, and you don't want to go
       through the pains of declaring a RE_Options object and setting  several
       options,  there  is a parallel method that give you such ability on the
       fly. You can concatenate several set_xxxxx()  member  functions,  since
       each  of  them returns a reference to its class object. For example, to
       pass PCRE_CASELESS, PCRE_EXTENDED, and PCRE_MULTILINE to a RE with  one
       statement, you may write:

          RE(" ^ xyz \\s+ .* blah$",


       The  "Consume"  operation may be useful if you want to repeatedly match
       regular expressions at the front of a string and skip over them as they
       match.  This requires use of the "StringPiece" type, which represents a
       sub-range of a real string. Like RE,  StringPiece  is  defined  in  the
       pcrecpp namespace.

         Example: read lines of the form "var = value" from a string.
            string contents = ...;                 // Fill string somehow
            pcrecpp::StringPiece input(contents);  // Wrap in a StringPiece

       could extract all words from a string by repeatedly calling

         pcrecpp::RE("(\\w+)").FindAndConsume(&input, &word)


       By default, if you pass a pointer to a numeric value, the corresponding
       text  is  interpreted  as  a  base-10  number. You can instead wrap the
       pointer with a call to one of the operators Hex(), Octal(), or CRadix()
       to  interpret  the text in another base. The CRadix operator interprets
       C-style "0" (base-8) and  "0x"  (base-16)  prefixes,  but  defaults  to

           int a, b, c, d;
           pcrecpp::RE re("(.*) (.*) (.*) (.*)");
           re.FullMatch("100 40 0100 0x40",
                        pcrecpp::Octal(&a), pcrecpp::Hex(&b),
                        pcrecpp::CRadix(&c), pcrecpp::CRadix(&d));

       will leave 64 in a, b, c, and d.


       You  can  replace the first match of "pattern" in "str" with "rewrite".
       Within "rewrite", backslash-escaped digits (\1 to \9) can  be  used  to
       insert  text  matching  corresponding parenthesized group from the pat-
       tern. \0 in "rewrite" refers to the entire matching text. For example:

         string s = "yabba dabba doo";
         pcrecpp::RE("b+").Replace("d", &s);

       will leave "s" containing "yada dabba doo". The result is true  if  the
       pattern matches and a replacement occurs, false otherwise.

       GlobalReplace  is  like Replace except that it replaces all occurrences
       of the pattern in the string with the  rewrite.  Replacements  are  not
       subject to re-matching. For example:

         string s = "yabba dabba doo";
         pcrecpp::RE("b+").GlobalReplace("d", &s);

       will  leave  "s"  containing  "yada dada doo". It returns the number of
       replacements made.

       Extract is like Replace, except that if the pattern matches,  "rewrite"
       is  copied into "out" (an additional argument) with substitutions.  The
       non-matching portions of "text" are ignored. Returns true iff  a  match
       occurred and the extraction happened successfully;  if no match occurs,
       the string is left unaffected.


       The C++ wrapper was contributed by Google Inc.
Man Pages Copyright Respective Owners. Site Copyright (C) 1994 - 2018 Hurricane Electric. All Rights Reserved.