(PHP 4 >= 4.1.0, PHP 5)
pcntl_signal — Installs a signal handler
$signo
, callable|int $handler
[, bool $restart_syscalls = true
] )
The pcntl_signal() function installs a new
signal handler or replaces the current signal handler for the signal indicated by signo.
signoThe signal number.
handler
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:
$signo
)signoNota:
Note that when you set a handler to an object method, that object's reference count is increased which makes it persist until you either change the handler to something else, or your script ends.
restart_syscallsSpecifies whether system call restarting should be used when this signal arrives.
Restituisce TRUE in caso di successo, FALSE in caso di fallimento.
| Versione | Descrizione |
|---|---|
| 4.3.0 | As of PHP 4.3.0 PCNTL uses ticks as the signal handle callback mechanism, which is much faster than the previous mechanism. This change follows the same semantics as using "user ticks". You must use the declare() statement to specify the locations in your program where callbacks are allowed to occur for the signal handler to function properly (as used in the example below). |
Example #1 pcntl_signal() example
<?php
// tick use required as of PHP 4.3.0
declare(ticks = 1);
// signal handler function
function sig_handler($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 SIGTERM to self...\n";
// send SIGUSR1 to current process id
posix_kill(posix_getpid(), SIGUSR1);
echo "Done\n";
?>
pcntl_signal() doesn't stack the signal handlers, but replaces them.