Which regular expression engine (flavor) does "Some Package" use?
Unfortunately, the regex section of many manuals starts with a tutorial, and often leaves this question unanswered. If the answer for the package that brought you to this page is not below, please add it, in a direct and short format, with links if applicable.
PHP Regex flavors
1.) PCRE (Perl Compatible Regular Expressions) preg* functions PHP: PCRE - Manual, PCRE man pages, perlre 2.) POSIX ERE (Extended Regular Expressions) ereg* functions -> DEPRECATED PHP: ereg - Manual, man pages 3.) POSIX ERE with multibyte support mb_ereg* functions PHP: mb_ereg - Manual
Feel free to add further information.