.TH PCRESAMPLE 3

.SH NAME

PCRE - Perl-compatible regular expressions

.SH "PCRE SAMPLE PROGRAM"

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A simple, complete demonstration program, to get you started with using PCRE,

is supplied in the file \fIpcredemo.c\fP in the PCRE distribution.

.P

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.

.P

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.

.P

If PCRE is installed in the standard include and library directories for your

system, you should be able to compile the demonstration program using this

command:

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  gcc -o pcredemo pcredemo.c -lpcre

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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

\fI/usr/local\fP, you can compile the demonstration program using a command

like this:

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.\" JOINSH

  gcc -o pcredemo -I/usr/local/include pcredemo.c \e

      -L/usr/local/lib -lpcre

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

this:

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  ./pcredemo 'cat|dog' 'the cat sat on the mat'

  ./pcredemo -g 'cat|dog' 'the dog sat on the cat'

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Note that there is a much more comprehensive test program, called

.\" HREF

\fBpcretest\fP,

.\"

which supports many more facilities for testing regular expressions and the

PCRE library. The \fBpcredemo\fP program is provided as a simple coding

example.

.P

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

\fBpcredemo\fP:

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

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

need to add

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  -R/usr/local/lib

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

.

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.SH AUTHOR

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Philip Hazel

University Computing Service

Cambridge CB2 3QH, England.

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.

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.SH REVISION

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Last updated: 23 January 2008

Copyright (c) 1997-2008 University of Cambridge.

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