pcre2sample(3) — Linux manual page


PCRE2SAMPLE(3)          Library Functions Manual          PCRE2SAMPLE(3)

NAME         top

       PCRE2 - Perl-compatible regular expressions (revised API)


       A simple, complete demonstration program to get you started with
       using PCRE2 is supplied in the file pcre2demo.c in the src
       directory in the PCRE2 distribution. A listing of this program is
       given in the pcre2demo documentation. If you do not have a copy
       of the PCRE2 distribution, you can save this listing to re-create
       the contents of pcre2demo.c.

       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.

       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.

       The code in pcre2demo.c 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.

       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:

         cc -o pcre2demo pcre2demo.c -lpcre2-8

       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 /usr/local, you can compile the
       demonstration program using a command like this:

         cc -o pcre2demo -I/usr/local/include pcre2demo.c \
            -L/usr/local/lib -lpcre2-8

       Once you have built the demonstration program, you can run simple
       tests like this:

         ./pcre2demo 'cat|dog' 'the cat sat on the mat'
         ./pcre2demo -g 'cat|dog' 'the dog sat on the cat'

       Note that there is a much more comprehensive test program, called
       pcre2test, 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
       pcre2demo program is provided as a relatively simple coding

       If you try to run pcre2demo when PCRE2 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: pcre2demo: fatal: libpcre2-8.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


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

AUTHOR         top

       Philip Hazel
       Retired from University Computing Service
       Cambridge, England.

REVISION         top

       Last updated: 02 February 2016
       Copyright (c) 1997-2016 University of Cambridge.

COLOPHON         top

       This page is part of the PCRE (Perl Compatible Regular
       Expressions) project.  Information about the project can be found
       at ⟨http://www.pcre.org/⟩.  If you have a bug report for this
       manual page, see
       ⟨http://bugs.exim.org/enter_bug.cgi?product=PCRE⟩.  This page was
       obtained from the tarball fetched from
       ⟨https://github.com/PhilipHazel/pcre2.git⟩ on 2023-12-22.  If you
       discover any rendering problems in this HTML version of the page,
       or you believe there is a better or more up-to-date source for
       the page, or you have corrections or improvements to the
       information in this COLOPHON (which is not part of the original
       manual page), send a mail to man-pages@man7.org

PCRE2 10.22                 02 February 2016              PCRE2SAMPLE(3)

Pages that refer to this page: pcre2api(3)