apache_child_terminate() will register the Apache process executing the current PHP request for termination once execution of PHP code it is completed. It may be used to terminate a process after a script with high memory consumption has been run as memory will usually only be freed internally but not given back to the operating system.
Note: The availability of this feature is controlled by the php.ini directive child_terminate, which is set to off by default.
This feature is also not available on multithreaded versions of apache like the win32 version.
See also exit().