(PHP 5, PHP 7) Change the priority of any process

(PHP 5 >= 5.3.0, PHP 7) Waits for signals

(PHP 5 >= 5.3.0, PHP 7) Calls signal handlers for pending signals

(PHP 4 >= 4.1.0, PHP 5, PHP 7) Returns the return code of a terminated child

(PHP 4 >= 4.1.0, PHP 5, PHP 7) Returns the signal which caused the child to stop

(PHP 4 >= 4.1.0, PHP 5, PHP 7) Forks the currently running process

(PHP 4 >= 4.1.0, PHP 5, PHP 7) Installs a signal handler

(PHP 4 >= 4.1.0, PHP 5, PHP 7) Checks whether the status code represents a termination due to a signal

(PHP 4 >= 4.1.0, PHP 5, PHP 7) Checks whether the child process is currently stopped

(PHP 4 >= 4.1.0, PHP 5, PHP 7) Checks if status code represents a normal exit