07-06-2008
Quote:
Originally Posted by
ramen_noodle
If your signal handling function is declared in main(), in the parent, before any fork and the children don't deviate from this handling then the the entire process group will react according to the described signal handler.
The signal handler is declared after the fork. This is one of the first things that the child processes do after they are invoked. Should this be done before the fork?
Thanks, Tuvia
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LEARN ABOUT PHP
pcntl_signal
PCNTL_SIGNAL(3) 1 PCNTL_SIGNAL(3)
pcntl_signal - Installs a signal handler
SYNOPSIS
bool pcntl_signal (int $signo, callable|int $handler, [bool $restart_syscalls = true])
DESCRIPTION
The pcntl_signal(3) function installs a new signal handler or replaces the current signal handler for the signal indicated by $signo.
PARAMETERS
o $signo
- The signal number.
o $handler
- The signal handler. This may be either a callable, which will be invoked to handle the signal, or either of the two global con-
stants 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:
void handler (int $signo)
o $signo
- The signal being handled.
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.
o $restart_syscalls
- Specifies whether system call restarting should be used when this signal arrives.
RETURN VALUES
Returns TRUE on success or FALSE on failure.
CHANGELOG
+--------+---------------------------------------------------+
|Version | |
| | |
| | Description |
| | |
+--------+---------------------------------------------------+
| 4.3.0 | |
| | |
| | As of PHP 4.3.0 PCNTL uses ticks as the signal |
| | handle callback mechanism, which is much faster |
| | than the previous mechanism. This change follows |
| | the same semantics as using "user ticks". You |
| | must use the declare() statement to specify the |
| | locations in your program where callbacks are |
| | allowed to occur for the signal handler to func- |
| | tion properly (as used in the example below). |
| | |
+--------+---------------------------------------------------+
EXAMPLES
Example #1
pcntl_signal(3) example
<?php
// tick use required as of PHP 4.3.0
declare(ticks = 1);
// signal handler function
function sig_handler($signo)
{
switch ($signo) {
case SIGTERM:
// handle shutdown tasks
exit;
break;
case SIGHUP:
// handle restart tasks
break;
case SIGUSR1:
echo "Caught SIGUSR1...
";
break;
default:
// handle all other signals
}
}
echo "Installing signal handler...
";
// setup signal handlers
pcntl_signal(SIGTERM, "sig_handler");
pcntl_signal(SIGHUP, "sig_handler");
pcntl_signal(SIGUSR1, "sig_handler");
// or use an object, available as of PHP 4.3.0
// pcntl_signal(SIGUSR1, array($obj, "do_something"));
echo"Generating signal SIGUSR1 to self...
";
// send SIGUSR1 to current process id
// posix_* functions require the posix extension
posix_kill(posix_getpid(), SIGUSR1);
echo "Done
";
?>
NOTES
pcntl_signal(3) doesn't stack the signal handlers, but replaces them.
SEE ALSO
pcntl_fork(3), pcntl_waitpid(3).
PHP Documentation Group PCNTL_SIGNAL(3)