System Event

System events, also known as signals, are software interrupts sent to a program to indicate that an important event has occurred.

By default, PHP reacts to system events. It may also handle those events by configuring a handler the pcntl_signal() function.

See also A Guide to the PHP PCNTL Library for Process Forking and Control.

Related : PHP Handlers, Process Control (pcntl), pcntl_signal()