The pcntl_signal() function installs a new
signal handler for the signal indicated by
signo
. The signal handler is set to
handler
which may be the name of a user
created function, or either of the two global constants SIG_IGN
or SIG_DFL. The optional restart_syscalls
specifies whether system call restarting should be used when this
signal arrives and defaults to TRUE.
Returns TRUE on success or FALSE on failure.
Note: The optional
restart_syscalls
parameter became available in PHP 4.3.0.
Note: The ability to use an object method as a callback became available in PHP 4.3.0. Note that when you set a handler to an object method, that object's reference count is increased which makes it persist until you either change the handler to something else, or your script ends.
Note: As of PHP 4.3.0 PCNTL uses ticks as the signal handle callback mechanism, which is much faster than the previous mechanism. This change follows the same semantics as using "user ticks". You must use the declare() statement to specify the locations in your program where callbacks are allowed to occur for the signal handler to function properly (as used in the above example).
See also pcntl_fork() and pcntl_waitpid().