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       PCRE - Perl-compatible regular expressions


       A simple, complete demonstration program, to get you started with using
       PCRE, is supplied in the file pcredemo.c in the  PCRE  distribution.  A
       listing  of this program is given in the pcredemo documentation. If you
       do not have a copy of the PCRE distribution, you can save this  listing
       to re-create pcredemo.c.

       The program compiles the regular expression that is its first argument,
       and matches it against the subject string in its  second  argument.  No
       PCRE  options  are  set,  and  default  character  tables  are used. If
       matching succeeds, the program outputs the portion of the subject  that
       matched, together with the contents of any captured substrings.

       If the -g option is given on the command line, the program then goes on
       to check for further matches of the same regular expression in the same
       subject  string.  The  logic  is  a  little  bit  tricky because of the
       possibility of matching an empty string. Comments in the  code  explain
       what is going on.

       If  PCRE  is  installed in the standard include and library directories
       for  your  operating  system,  you  should  be  able  to  compile   the
       demonstration program using this command:

         gcc -o pcredemo pcredemo.c -lpcre

       If  PCRE is installed elsewhere, you may need to add additional options
       to the command line. For example, on a Unix-like system that  has  PCRE
       installed  in  /usr/local,  you  can  compile the demonstration program
       using a command like this:

         gcc -o pcredemo -I/usr/local/include pcredemo.c \
             -L/usr/local/lib -lpcre

       Once you have compiled the demonstration program, you  can  run  simple
       tests like this:

         ./pcredemo ’cat|dog’ ’the cat sat on the mat’
         ./pcredemo -g ’cat|dog’ ’the dog sat on the cat’

       Note  that  there  is  a  much  more comprehensive test program, called
       pcretest, which supports  many  more  facilities  for  testing  regular
       expressions and the PCRE library. The pcredemo program is provided as a
       simple coding example.

       When you try to run pcredemo when PCRE is not installed in the standard
       library  directory,  you  may  get an error like this on some operating
       systems (e.g. Solaris):
 a.out: fatal: open failed:  No  such  file  or

       This  is  caused  by  the  way  shared  library  support works on those
       systems. You need to add


       (for example) to the compile command to get round this problem.


       Philip Hazel
       University Computing Service
       Cambridge CB2 3QH, England.


       Last updated: 30 September 2009
       Copyright (c) 1997-2009 University of Cambridge.