Resource Limits

This sets the maximum amount of memory in bytes that a script is allowed to allocate. This helps prevent poorly written scripts for eating up all available memory on a server. In order to use this directive you must have enabled it at compile time. So, your configure line would have included: --enable-memory-limit. Note that you have to set it to -1 if you don't want any limit for your memory.

As of PHP 4.3.2, and when memory_limit is enabled, the PHP function memory_get_usage() is made available.

When an integer is used, the value is measured in bytes. You may also use shorthand notation as described in this FAQ.