pcre (Perl Compatible Regular Expressions) 包括 perl 兼容的正规表达式库.这些在执行正规表达式模式匹配时用与Perl 5同样的语法和语义是很有用的.
PCRE(Perl Compatible Regular Expressions中文含义：perl语言兼容正则表达式)是一个用C语言编写的正则表达式函数库，由菲利普.海泽(Philip Hazel)编写。PCRE是一个轻量级的函数库，比Boost之中的正则表达式库小得多。PCRE十分易用，同时功能也很强大，性能超过了POSIX正则表达式库和一些经典的正则表达式库。
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 proprietary 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. PCRE has also found its way into some well known commercial products, like Apple Safari. Some other interesting projects using PCRE include Chicken, Ferite, Onyx, Hypermail, Leafnode, Askemos, and Wenlin.