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 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 demonstration program, which uses  the  original  PCRE  8-bit  library,  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

       In a Windows environment, if you want to statically link the  program  against  a  non-dll
       pcre.a file, you must uncomment the line that defines PCRE_STATIC before including pcre.h,
       because otherwise the pcre_malloc() and pcre_free() exported functions  will  be  declared
       __declspec(dllimport), with unwanted results.

       Once you have compiled and linked 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 both PCRE libraries. The pcredemo
       program is provided as a simple coding example.

       If 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):

         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.

AUTHOR

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

REVISION

       Last updated: 10 January 2012
       Copyright (c) 1997-2012 University of Cambridge.