(PHP 5 >= 5.2.0, PHP 7) Returns the error code of the last PCRE regex execution

(PHP 4, PHP 5, PHP 7) Perform a global regular expression match

(PHP 7) Perform a regular expression search and replace using callbacks

(PHP 4, PHP 5, PHP 7) Perform a regular expression match

(PHP 4, PHP 5, PHP 7) Return array entries that match the pattern

(PHP 4, PHP 5, PHP 7) Perform a regular expression search and replace

(PHP 4 >= 4.0.5, PHP 5, PHP 7) Perform a regular expression search and replace using a callback

Examples: Use of this modifier is discouraged, as it can easily introduce security vulnerabilites:

(PHP 4, PHP 5, PHP 7) Split string by a regular expression