pcntl_signal

(PHP 4 >= 4.1.0, PHP 5, PHP 7)

pcntl_signal — Installs a signal handler

Descripción

pcntl_signal ( int $signo , callable|int $handler [, bool $restart_syscalls = TRUE ] ) : bool

The pcntl_signal() function installs a new signal handler or replaces the current signal handler for the signal indicated by signo.

Parámetros

signo

The 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:

handler ( int $signo , mixed $signinfo ) : void
signo
The signal being handled.
siginfo
If operating systems supports siginfo_t structures, this will be an array of signal information dependent on the signal.

Nota:

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_syscalls

Specifies whether system call restarting should be used when this signal arrives.

Valores devueltos

Devuelve TRUE en caso de éxito o FALSE en caso de error.

Historial de cambios

Versión Descripción
7.1.0 As of PHP 7.1.0 the handler callback is given a second argument containing the signinfo of the specific signal. This data is only supplied if the operating system has the signinfo_t structure. If the OS does not implement siginfo_t NULL is supplied.

Ejemplos

Ejemplo #1 pcntl_signal() example

<?php
// tick use required
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
// 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";

?>

Notas

pcntl_signal() doesn't stack the signal handlers, but replaces them.

Ver también