Supported Versions: PHP 4, PHP 5, PHP 7, PHP 8
Delay execution in microseconds
usleep(int $microseconds): void
        }



        if (
$timeout 0) {

            
\usleep($timeout);

        } elseif (
$timeout === null) {
            $this->fail("Failed to fork child process!");

        } else if (
$childPid === 0) {


            
usleep(20000);

            
posix_kill($currentPidconstant($signal));

            die();

        }