The PCRE library is a set of functions that implement regular expression
pattern matching using the same syntax and semantics as Perl 5, with just
a few differences. The current implementation corresponds to Perl 5.005.
PCRE is  used by many programs, including Exim, Postfix, and PHP.

Written by: Phil Hazel <ph10@cam.ac.uk>

WWW: http://www.pcre.org/