PHP: Runtime Configuration - Manual

Runtime Configuration

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

**PCRE Configuration Options**
Name	Default	Changeable
pcre.backtrack_limit	"1000000"	`INI_ALL`
pcre.recursion_limit	"100000"	`INI_ALL`
pcre.jit	"1"	`INI_ALL`

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

Here's a short explanation of the configuration directives.

pcre.backtrack_limitint: PCRE's backtracking limit. Defaults to 100000 for PHP < 5.3.7.
pcre.recursion_limitint: 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.jitbool: Whether PCRE's just-in-time compilation is going to be used.