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pcntl_signal
(PHP 4 >= 4.1.0, PHP 5, PHP 7)
pcntl_signal — Installs a signal handler
Description
$signo
, callable|int $handler
[, bool $restart_syscalls = TRUE
] ) : bool
The pcntl_signal() function installs a new
signal handler or replaces the current signal handler for the signal indicated by signo.
Parameters
-
signo -
The signal number.
-
handler -
The signal handler. This may be either a callable, which will be invoked to handle the signal, or either of the two global constants
SIG_IGNorSIG_DFL, which will ignore the signal or restore the default signal handler respectively.If a callable is given, it must implement the following signature:
-
signo - The signal being handled.
-
siginfo - If operating systems supports siginfo_t structures, this will be an array of signal information dependent on the signal.
Note:
Note that when you set a handler to an object method, that object's reference count is increased which makes it persist until you either change the handler to something else, or your script ends.
-
-
restart_syscalls -
Specifies whether system call restarting should be used when this signal arrives.
Changelog
| Version | Description |
|---|---|
| 7.1.0 | As of PHP 7.1.0 the handler callback is given a second argument containing the signinfo of the specific signal. This data is only supplied if the operating system has the signinfo_t structure. If the OS does not implement siginfo_t NULL is supplied. |
Examples
Example #1 pcntl_signal() example
<?php
// tick use required
declare(ticks = 1);
// signal handler function
function sig_handler($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";
?>
See Also
- pcntl_fork() - Forks the currently running process
- pcntl_waitpid() - Waits on or returns the status of a forked child
English translation
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Document created the 30/01/2003, last modified the 26/10/2018
Source of the printed document:https://www.gaudry.be/en/php-rf-pcntl-signal.html
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References
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