The pcntl_signal() function installs a new signal handler or replaces the current signal handler for the signal indicated by signo
.
The signal number.
The signal handler. This may be either a callable, which will be invoked to handle the signal, or either of the two global constants SIG_IGN
or SIG_DFL
, which will ignore the signal or restore the default signal handler respectively.
If a callable is given, it must implement the following signature:
$signo
)Specifies whether system call restarting should be used when this signal arrives.
Returns TRUE
on success or FALSE
on failure.
As of PHP 4.3.0 PCNTL uses ticks as the signal handle callback mechanism, which is much faster than the previous mechanism. This change follows the same semantics as using "user ticks". You must use the declare() statement to specify the locations in your program where callbacks are allowed to occur for the signal handler to function properly (as used in the example below).
<?php // tick use required as of PHP 4.3.0 declare(ticks = 1); // signal handler function function sig_handler($signo) { switch ($signo) { case SIGTERM: // handle shutdown tasks exit; break; case SIGHUP: // handle restart tasks break; case SIGUSR1: echo "Caught SIGUSR1...\n"; break; default: // handle all other signals } } echo "Installing signal handler...\n"; // setup signal handlers pcntl_signal(SIGTERM, "sig_handler"); pcntl_signal(SIGHUP, "sig_handler"); pcntl_signal(SIGUSR1, "sig_handler"); // or use an object, available as of PHP 4.3.0 // pcntl_signal(SIGUSR1, array($obj, "do_something")); echo"Generating signal SIGUSR1 to self...\n"; // send SIGUSR1 to current process id // posix_* functions require the posix extension posix_kill(posix_getpid(), SIGUSR1); echo "Done\n"; ?>
Please login to continue.