php man page for pcntl_fork

PCNTL_FORK(3)								 1							     PCNTL_FORK(3)

pcntl_fork - Forks the currently running process

SYNOPSIS
       int pcntl_fork (void  )

DESCRIPTION
	The pcntl_fork(3) function creates a child process that differs from the parent process only in its PID and PPID. Please see your system's
       fork(2) man page for specific details as to how fork works on your system.

RETURN VALUES
	On success, the PID of the child process is returned in the parent's thread of execution, and a 0 is returned in  the  child's	thread	of
       execution. On failure, a -1 will be returned in the parent's context, no child process will be created, and a PHP error is raised.

EXAMPLES
       Example #1

	      pcntl_fork(3) example

	      <?php

	      $pid = pcntl_fork();
	      if ($pid == -1) {
		   die('could not fork');
	      } else if ($pid) {
		   // we are the parent
		   pcntl_wait($status); //Protect against Zombie children
	      } else {
		   // we are the child
	      }

	      ?>

SEE ALSO
       pcntl_waitpid(3), pcntl_signal(3), setproctitle(3).

PHP Documentation Group 													     PCNTL_FORK(3)