Опис

pcntl_signal(int $signal, 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 signal.

Параметри

signal

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 $siginfo): void

signal: The signal being handled.
siginfo: If operating systems supports siginfo_t structures, this will be an array of signal information dependent on the signal.

Зауваження:
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.

Значення, що повертаються

Повертає true у разі успіху або false в разі помилки.

Журнал змін

Версія Опис

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

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

Приклади

Приклад #1 pcntl_signal() example

<?php
pcntl_async_signals(true);

// 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";

?>

Примітки

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

Dispatch Methods

There are several methods of dispatching signal handlers:

Asynchronous dispatch with pcntl_async_signals() enabled. This is the recommended method
Setting tick frequency
Manual dispatch with pcntl_signal_dispatch()

When signals are dispatched asynchronously or using tick-based execution, blocking functions like sleep() may be interrupted.

Прогляньте також

» Signal (IPC) on Wikipedia
pcntl_async_signals() - Enable/disable asynchronous signal handling or return the old setting
pcntl_fork() - Forks the currently running process
pcntl_signal_dispatch() - Calls signal handlers for pending signals
pcntl_waitpid() - Waits on or returns the status of a forked child