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| <head> |
| <title>pcre2sample specification</title> |
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| <body bgcolor="#FFFFFF" text="#00005A" link="#0066FF" alink="#3399FF" vlink="#2222BB"> |
| <h1>pcre2sample man page</h1> |
| <p> |
| Return to the <a href="index.html">PCRE2 index page</a>. |
| </p> |
| <p> |
| This page is part of the PCRE2 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. |
| <br> |
| <br><b> |
| PCRE2 SAMPLE PROGRAM |
| </b><br> |
| <P> |
| A simple, complete demonstration program to get you started with using PCRE2 is |
| supplied in the file <i>pcre2demo.c</i> in the <b>src</b> directory in the PCRE2 |
| distribution. A listing of this program is given in the |
| <a href="pcre2demo.html"><b>pcre2demo</b></a> |
| documentation. If you do not have a copy of the PCRE2 distribution, you can |
| save this listing to re-create the contents of <i>pcre2demo.c</i>. |
| </P> |
| <P> |
| The demonstration program compiles the regular expression that is its |
| first argument, and matches it against the subject string in its second |
| argument. No PCRE2 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> |
| <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> |
| <P> |
| The code in <b>pcre2demo.c</b> is an 8-bit program that uses the PCRE2 8-bit |
| library. It handles strings and characters that are stored in 8-bit code units. |
| By default, one character corresponds to one code unit, but if the pattern |
| starts with "(*UTF)", both it and the subject are treated as UTF-8 strings, |
| where characters may occupy multiple code units. |
| </P> |
| <P> |
| If PCRE2 is installed in the standard include and library directories for your |
| operating system, you should be able to compile the demonstration program using |
| a command like this: |
| <pre> |
| cc -o pcre2demo pcre2demo.c -lpcre2-8 |
| </pre> |
| If PCRE2 is installed elsewhere, you may need to add additional options to the |
| command line. For example, on a Unix-like system that has PCRE2 installed in |
| <i>/usr/local</i>, you can compile the demonstration program using a command |
| like this: |
| <pre> |
| cc -o pcre2demo -I/usr/local/include pcre2demo.c -L/usr/local/lib -lpcre2-8 |
| </pre> |
| Once you have built the demonstration program, you can run simple tests like |
| this: |
| <pre> |
| ./pcre2demo 'cat|dog' 'the cat sat on the mat' |
| ./pcre2demo -g 'cat|dog' 'the dog sat on the cat' |
| </pre> |
| Note that there is a much more comprehensive test program, called |
| <a href="pcre2test.html"><b>pcre2test</b>,</a> |
| which supports many more facilities for testing regular expressions using all |
| three PCRE2 libraries (8-bit, 16-bit, and 32-bit, though not all three need be |
| installed). The |
| <a href="pcre2demo.html"><b>pcre2demo</b></a> |
| program is provided as a relatively simple coding example. |
| </P> |
| <P> |
| If you try to run |
| <a href="pcre2demo.html"><b>pcre2demo</b></a> |
| when PCRE2 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: pcre2demo: fatal: libpcre2-8.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. |
| </P> |
| <br><b> |
| AUTHOR |
| </b><br> |
| <P> |
| Philip Hazel |
| <br> |
| University Computing Service |
| <br> |
| Cambridge, England. |
| <br> |
| </P> |
| <br><b> |
| REVISION |
| </b><br> |
| <P> |
| Last updated: 02 February 2016 |
| <br> |
| Copyright © 1997-2016 University of Cambridge. |
| <br> |
| <p> |
| Return to the <a href="index.html">PCRE2 index page</a>. |
| </p> |