pcntl_exec

maxime at diametrick dot com (2013-05-02 06:20:21)

An alternative for Windows environment is to use the COM object. With this, you can start child process with Apache, or php.exe as parent process. Very useful for CLI or console PHC-Win applications.
if(!function_exists('pcntl_exec')){
function pcntl_exec($path,$args=array()){
if(is_string($args)) $args = array($args);
if(count($args)) $path = '"'.$path.'"';
$shell = new COM('WScript.Shell');
$shell->run($path.(count($args) ? ' '.implode(' ',$args) : ''),0,true);
}
}
Very useful too when you want to use ansicon. Instead of make a .bat file with ansicon -p and php .... (somefile).php, in your .php file you can put this on top of your code:
pcntl_exec('ansicon -p');
BINGO!

trevorpearce at gmail dot com (2012-01-22 18:36:07)

I spent a lot of time trying to figure this powerful option out so I didn't get error 2 or error 8. The documentation says it can execute a binary file and here is a good example that works that I found;

<?php
    print "Before\\n";
    pcntl_exec("/usr/bin/uptime");
    print "After\\n";
?>

However I wanted it to run another php program and after wasting a lot of time I finally got it.

<?php
$tasks2=array('/var/www/example.php');
pcntl_exec("/usr/bin/php",$tasks2);
?>

The php script has to be in an array and you execute the binary php file

I'll be adding this to launching a child and run it seperately using this function

<?php
function launchchild($programexe,$programvars)
{
//foreach ($tasks as $key => $v){
   switch ($pid = pcntl_fork()) {
      case -1:
         // @fail
         die('Fork failed');
         break;

      case 0:
         // @child: Include() misbehaving code here
         print "FORK: Child #{$x} \\n";
         echo "child after fork:", getmypid(), PHP_EOL;
         pcntl_exec($programexe,$programvars);
         // generate_fatal_error(); // Undefined function
         break;

      default:
         // @parent
         print "FORK: $x Parent\\n";
         echo "parent after fork:", getmypid(), PHP_EOL;
         // pcntl_waitpid($pid, $status);
         break;
   }

print "Done! :^)\\n\\n";
}
?>

fahadsadah at gmail dot com dot please dot remove dot this (2008-06-28 07:44:49)

Just a note regarding what rbemrose at vgmusic dot com said:
Once the executed process ends, control returns to the webserver process.

rbemrose at vgmusic dot com (2008-02-06 14:44:18)

As a side note, if I'm reading the comments below correctly, you should not run this if you're using a PHP webserver module, as it will replace the webserver's process with whatever process you're telling it to run.

agodong at verizon dot net (2006-12-07 10:47:19)

Some people might find it useful to run other program using the same process as a different user. This is very usefull if the script is running under root. Here is a simple code to achieve that under *nix PHP CLI:

#!/usr/bin/php -q
<?php
//Enter run-as user below (argument needed to be passed when the script is called), otherwise it will run as the caller user process.

$username = $_SERVER['argv'][1];

$user = posix_getpwnam($username);
posix_setuid($user['uid']);
posix_setgid($user['gid']);
pcntl_exec('/path/to/cmd');
?>

I use this as a part of socket program so that a program can be run under different user from remote location.

eric kilfoil (2006-10-24 10:01:12)

The pcntl_exec() function works exactly like the standard (unix-style) exec() function. It differs from the regular PHP exec() function in that the process calling the pcntl_exec() is replaced with the process that gets called. This is the ideal method for creating children. In a simple example (that does no error checking):
switch (pcntl_fork()) {
case 0:
$cmd = "/path/to/command";
$args = array("arg1", "arg2");
pcntl_exec($cmd, $args);
// the child will only reach this point on exec failure,
// because execution shifts to the pcntl_exec()ed command
exit(0);
default:
break;
}
// parent continues
echo "I am the parent";
--
since this is not being executed through a shell, you must provide the exact path from the filesystem root. Look at the execve() man page for more information.

michael dot ferre at mobileway dot com (2002-11-20 03:28:23)

//To complete my last note
//If you use some object in your php code
//You will have some problem if you do a exit after include the
//child scripts
//You must use posix_kill() like that :
$CHILD_PID = pcntl_fork();
if($CHILD_PID == 0)
{
include ($script_path);
posix_kill(getmypid(),9);
}
//This code is very simple it can be ameliorate ;)

michael dot ferre at mobileway dot com (2002-11-19 04:19:21)