PCRE10.31

The PCRE library is a set of functions that implement regular expression pattern matching using the same syntax and semantics as Perl 5. PCRE has its own native API, as well as a set of wrapper functions that correspond to the POSIX regular expression API. The PCRE library is free, even for building commercial software.

PCRE was originally written for the Exim MTA, but is now used by many high-profile open source projects, including Apache, PHP, KDE, Postfix, Analog, and Nmap. Some other interesting projects using PCRE include Ferite, Onyx, Hypermail, Leafnode, and Askemos.