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<title>pcresample specification</title>
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<h1>pcresample man page</h1>

Return to the <a href="index.html">PCRE index page</a>.


This page is part of the PCRE HTML documentation. It was generated automatically
from the original man page. If there is any nonsense in it, please consult the
man page, in case the conversion went wrong.
 
 
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
<a href="pcredemo.html">pcredemo</a>
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:
<pre>
 gcc -o pcredemo pcredemo.c -lpcre
</pre>
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:
<pre>
 gcc -o pcredemo -I/usr/local/include pcredemo.c -L/usr/local/lib -lpcre
</pre>
Once you have compiled the demonstration program, you can run simple tests like
this:
<pre>
 ./pcredemo 'cat|dog' 'the cat sat on the mat'
 ./pcredemo -g 'cat|dog' 'the dog sat on the cat'
</pre>
Note that there is a much more comprehensive test program, called
<a href="pcretest.html">pcretest,</a>
which supports many more facilities for testing regular expressions and the
PCRE library. The
<a href="pcredemo.html">pcredemo</a>
program is provided as a simple coding example.


When you try to run
<a href="pcredemo.html">pcredemo</a>
when PCRE is not installed in the standard library directory, you may get an
error like this on some operating systems (e.g. Solaris):
<pre>
 ld.so.1: a.out: fatal: libpcre.so.0: open failed: No such file or directory
</pre>
This is caused by the way shared library support works on those systems. You
need to add
<pre>
 -R/usr/local/lib
</pre>
(for example) to the compile command to get round this problem.

 
AUTHOR
 

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

 
REVISION
 

Last updated: 30 September 2009
 
Copyright &copy; 1997-2009 University of Cambridge.
 

Return to the <a href="index.html">PCRE index page</a>.

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