Background exec() ?

Hey all,

Is there a good way to run a process in the *background* via exec(),
system(), or some other method?

This works, but the parent process waits for the child to end:

exec('php -d noscreen=1 VOL1:/Apache2/htdocs/ExecTest/child.php');

This seems to start a background process, but the console wants a key to
be pressed before the script exits:

exec('bash -c "php -d noscreen=1
VOL1:/Apache2/htdocs/ExecTest/child.php"');


Thanks!