Runtime Configuration

The behaviour of these functions is affected by settings in php.ini.

PCRE Configuration Options

Name	Default	Changeable	Changelog
pcre.backtrack_limit	"1000000"	PHP_INI_ALL
pcre.recursion_limit	"100000"	PHP_INI_ALL
pcre.jit	"1"	PHP_INI_ALL

For further details and definitions of the PHP_INI_* modes, see the Where a configuration setting may be set.

Here's a short explanation of the configuration directives.

pcre.backtrack_limit int

PCRE's backtracking limit. Defaults to 100000 for PHP < 5.3.7.

pcre.recursion_limit int

PCRE's recursion limit. Please note that if you set this value to a high number you may consume all the available process stack and eventually crash PHP (due to reaching the stack size limit imposed by the Operating System).

pcre.jit bool

Whether PCRE's just-in-time compilation is going to be used.