PCRE(3)                                                 PCRE(3)





NAME
       PCRE - Perl-compatible regular expressions

PCRE SAMPLE PROGRAM

       A  simple,  complete  demonstration  program, to get you
       started with using PCRE, is supplied in the  file  pcre-
       demo.c in the PCRE distribution.

       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  suc-
       ceeds,  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 pro-
       gram 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 system, you should be able to com-
       pile 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 pro-
       gram, called pcretest, which supports many more  facili-
       ties  for  testing  regular  expressions  and  the  PCRE
       library. The pcredemo program is provided  as  a  simple
       coding example.

       On  some  operating systems (e.g. Solaris), when PCRE is
       not installed in the standard library directory, you may
       get an error like this when you try to run pcredemo:

         ld.so.1:  a.out:  fatal: libpcre.so.0: open failed: No
       such file or directory

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

         -R/usr/local/lib

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

Last updated: 09 September 2004
Copyright (c) 1997-2004 University of Cambridge.



                                                        PCRE(3)
