Úvod

Process Control support in PHP implements the Unix style of process creation, program execution, signal handling and process termination. Process Control should not be enabled within a webserver environment and unexpected results may happen if any Process Control functions are used within a webserver environment.

This documentation is intended to explain the general usage of each of the Process Control functions. For detailed information about Unix process control you are encouraged to consult your systems documentation including fork(2), waitpid(2) and signal(2) or a comprehensive reference such as Advanced Programming in the UNIX Environment by W. Richard Stevens (Addison-Wesley).

Požadavky

Tyto funkce jsou k dispozici jako součást standardního modulu, který je vždy dostupný.

Instalace

Process Control support in PHP is not enabled by default. You will need to use the --enable-pcntl configuration option when compiling PHP to enable Process Control support.

Konfigurace běhu

Toto rozšíření nemá definováno žádné konfigurační direktivy.

Typy prostředků

Toto rozšíření nemá definován žádný typ prostředku (resource).

Předdefinované konstanty

The following list of signals are supported by the Process Control functions. Please see your systems signal(7) man page for details of the default behavior of these signals.

Příklady

This example forks off a daemon process with a signal handler.

<?php

$pid = pcntl_fork();
if ($pid == -1) {
     die("could not fork"); 
} else if ($pid) {
     exit(); // we are the parent 
} else {
     // we are the child
}

// detatch from the controlling terminal
if (!posix_setsid()) {
    die("could not detach from terminal");
}

// setup signal handlers
pcntl_signal(SIGTERM, "sig_handler");
pcntl_signal(SIGHUP, "sig_handler");

// loop forever performing tasks
while(1) {

    // do something interesting here

}

function sig_handler($signo) {

     switch($signo) {
         case SIGTERM:
             // handle shutdown tasks
             exit;
             break;
         case SIGHUP:
             // handle restart tasks
             break;
         default:
             // handle all other signals
     }

}

?>

Viz také

A look at the section about POSIX functions may be useful.