error status - how to get it

Hi there, How can I determine if a script is terminated normally or with an error (execution time out, memory limit exceeded, etc.)? I'm writing a new PHP extension, and I need to generate an alert if the script is terminted due to a timeout error or memory limit exceeded error. However, I cannot find a way to determine the error status. For time out error, there is a global flag, PG(connection_status), which supposedly should be set to PHP_CONNECTION_TIMEOUT when timeout happens, but the flag remains as PHP_CONNECTION_NORMAL. For memory exceeded error, there is also a global flag, AG(memory_exhausted). Unfortunately the flag doesn't change when a memory error happens. And there is no other global error status, error msg, or errno indicating the errors. Can somebody suggest a possible solution for me to get the error? Thanks a lot. --Charmaine