NYCPHP Meetup

[max goldberg]

I'm using the pcntl_fork function to split up a workload between a bunch 
of processes.
I've managed to separate the master from the children, but I am having 
some trouble with
the pcntl_waitpid function.  I was wondering if anyone has any 
documentation or examples
of it's usage. I looked at 
http://www.php.net/manual/en/function.pcntl-waitpid.php but it
still isn't really clear to me.

Here is a quick script I made up:
---
<?php /* -*- C++ -*- */

$max_children = 3;
$is_daemon    = true;
$forks        = 0;

if ($is_daemon) {
  echo 'Master Starting Up. [' . date(' Y-m-d H:i:s ') . '] ( ' . 
mktime() . " ) \n";

  for ($forks = 1; $forks <= $max_children; $forks++) {

    $new_pid = pcntl_fork();

    if ($new_pid == -1) {
      die('Could not fork.');
    }
    else if ($new_pid != 0) {
      echo "[ MASTER ] Starting thread with pid $new_pid ... \n";
      $thread_list[$forks] = $new_pid;
    }
    else {
      echo "[ CHILD  ]  Fork Initializing....!\n";
      $is_daemon = false;
      $i_am = $forks;
      break;
    }
  }
}

if ($is_daemon == true) {
  $i_am = 0;
}
else {
  $seconds = (int)($i_am * 20);
  echo "[ CHILD  ] Sleeping for $seconds!\n";
  sleep($seconds);
  echo "[ CHILD  ] Done Sleeping!\n";
  exit(1);
}

if ($is_daemon == true) {
  $waitpid_status = null;
  echo "[ MASTER ] Waiting For Children to Die!\n";
  pcntl_waitpid (-1, &$waitpid_status, WUNTRACED);
  echo "[ MASTER ] My Children are dead!\n";
}

?>
---

The result is :
Master Starting Up. [ 2003-10-10 12:24:17 ] ( 1065803057 )
[ CHILD  ]  Fork Initializing....!
[ CHILD  ] Sleeping for 20!
[ MASTER ] Starting thread with pid 28773 ...
[ MASTER ] Starting thread with pid 28774 ...
[ CHILD  ]  Fork Initializing....!
[ CHILD  ] Sleeping for 40!
[ MASTER ] Starting thread with pid 28775 ...
[ CHILD  ]  Fork Initializing....!
[ CHILD  ] Sleeping for 60!
[ MASTER ] Waiting For Children to Die!
[ CHILD  ] Done Sleeping!
[ MASTER ] My Children are dead!
[max at computer:/] $ [ CHILD  ] Done Sleeping!
[ CHILD  ] Done Sleeping!


Obviously the master is only waiting for the first child to die out 
before it responds
that they are all done.I have a few options, one of which is keep an 
array of the pid's
of each fork and then loop and wait for each of them.I was just 
wondering if it was
possible to have it wait for any and all forked processes with one 
command. Does
anyone have any experience with this?

Thanks, and sorry for the long mail!
-Max