php man page for pcntl_wait

PCNTL_WAIT(3)								 1							     PCNTL_WAIT(3)

pcntl_wait - Waits on or returns the status of a forked child

SYNOPSIS
       int pcntl_wait (int  &$status, [int  $options])

DESCRIPTION
	The  wait  function  suspends execution of the current process until a child has exited, or until a signal is delivered whose action is to
       terminate the current process or to call a signal handling function. If a child has already exited by the time of  the  call  (a  so-called
       "zombie" process), the function returns immediately. Any system resources used by the child are freed. Please see your system's wait(2) man
       page for specific details as to how wait works on your system.

       Note

	       This function is equivalent to calling pcntl_waitpid(3) with a -1$pid and no $options.

PARAMETERS
	      o $status
		-pcntl_wait(3) will store status information in the $status parameter which  can  be  evaluated  using	the  following	functions:
		pcntl_wifexited(3), pcntl_wifstopped(3), pcntl_wifsignaled(3), pcntl_wexitstatus(3), pcntl_wtermsig(3) and pcntl_wstopsig(3).

	      o $options
		- If wait3 is available on your system (mostly BSD-style systems), you can provide the optional $options parameter. If this param-
		eter is not provided, wait will be used for the system call. If wait3 is not available, providing a value for $options
			will have no effect. The value of $options
			is the value of zero or more of the following two constants OR'ed together:

	      Possible values for $options

	      +----------+---------------------------------------------------+
	      | 	 |						     |
	      | WNOHANG  |						     |
	      | 	 |						     |
	      | 	 |     Return immediately if no child has exited.    |
	      | 	 |						     |
	      | 	 |						     |
	      |WUNTRACED |						     |
	      | 	 |						     |
	      | 	 |  Return for children which are stopped, and whose |
	      | 	 | status has not been reported.		     |
	      | 	 |						     |
	      +----------+---------------------------------------------------+
RETURN VALUES
       pcntl_wait(3)  returns  the process ID of the child which exited, -1 on error or zero if WNOHANG was provided as an option (on wait3-avail-
       able systems) and no child was available.

SEE ALSO
       pcntl_fork(3), pcntl_signal(3), pcntl_wifexited(3),  pcntl_wifstopped(3),  pcntl_wifsignaled(3),  pcntl_wexitstatus(3),	pcntl_wtermsig(3),
       pcntl_wstopsig(3), pcntl_waitpid(3).

PHP Documentation Group 													     PCNTL_WAIT(3)