fork_test.php

<?php

$pids = [];
for($i=0; $i<10; $i++){
    
    $pid = pcntl_fork();
    if( $pid == -1 ){
        die('could not fork');
    }
    if( $pid ){ # 부모 : 자식 PID 누적
        $pids[] = $pid;
    }
    else{ # 자식 : 작업하고 바로 종료.
    	$sleep = rand(1,5);
    	$pid = getmypid();
        echo "CHILD #$pid - Sleep for $sleep seconds\n";
        sleep($sleep);
        echo "CHILD #$pid - Bye!!\n";
        exit;
    }
}

foreach($pids as $pid){
	print "PARENT - waiting #$pid\n";
    pcntl_waitpid($pid, $status, WUNTRACED);
}
print "done\n";

CHILD #69644 - Sleep for 2 seconds
CHILD #69645 - Sleep for 3 seconds
CHILD #69646 - Sleep for 4 seconds
CHILD #69647 - Sleep for 1 seconds
CHILD #69648 - Sleep for 1 seconds
CHILD #69649 - Sleep for 3 seconds
CHILD #69650 - Sleep for 4 seconds
CHILD #69651 - Sleep for 5 seconds
CHILD #69652 - Sleep for 5 seconds
PARENT - waiting# 69644
CHILD #69653 - Sleep for 5 seconds
CHILD #69647 - Bye!!
CHILD #69648 - Bye!!
CHILD #69644 - Bye!!
PARENT - waiting# 69645
CHILD #69645 - Bye!!
CHILD #69649 - Bye!!
PARENT - waiting# 69646
CHILD #69646 - Bye!!
CHILD #69650 - Bye!!
PARENT - waiting# 69647
PARENT - waiting# 69648
PARENT - waiting# 69649
PARENT - waiting# 69650
PARENT - waiting# 69651
CHILD #69652 - Bye!!
CHILD #69651 - Bye!!
CHILD #69653 - Bye!!
PARENT - waiting# 69652
PARENT - waiting# 69653
done