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PCRESAMPLE(3)                                                    PCRESAMPLE(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. 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 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 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  com-
       mand 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 the PCRE library. The pcredemo program is provided as a simple coding exam-
       ple.

       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: 17 November 2010
       Copyright (c) 1997-2010 University of Cambridge.



                                                                 PCRESAMPLE(3)