PHP: 运行时配置

[edit] Last updated: Fri, 25 May 2012

运行时配置

这些函数的行为受 php.ini 中的设置影响。

**PCRE配置选项**
名字	默认	可修改范围	更新日志
pcre.backtrack_limit	"100000"	PHP_INI_ALL	php 5.2.0可用.
pcre.recursion_limit	"100000"	PHP_INI_ALL	php 5.2.0可用.

有关 PHP_INI_* 样式的更多详情与定义，见 Where a configuration setting may be set。

这是配置指令的简短说明。

pcre.backtrack_limit integer: PCRE的回溯限制.
pcre.recursion_limit integer: PCRE的递归限制. 请注意, 如果讲这个值设置为一个很大的数字, 你可能会消耗掉所有的进程可用堆栈, 最终导致php崩溃(直到达到系统限制的堆栈大小).

add a note User Contributed Notes 运行时配置

php at richardneill dot org 14-Jan-2011 09:55


pcre.backtrack_limit defaults to 100k.  This is rather conservative.

It is limited by RAM size, not the ulimit on stack-size.



On a (2009-era) netbook, I can set pcre.backtrack_limit to 100 million, and the regex will happily process a 90 million character string in about 3 seconds. YMMV.

chris at ocproducts dot com 02-Jul-2010 07:42


pcre.backtrack_limit sets the maximum bind length PREG calls (e.g. preg_replace_callback) can make. However the actual maximum seems to be approximately half the value set here, possibly due to the character encoding that PCRE runs with internally.

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