PHP - 子进程未正确退出

Question

我有以下 PHP 脚本。我需要用 5 个不同的子进程执行 5 个不同的任务(使用 pcntl_fork() 函数)。 Childs 被正确创建并且他们做他们的事情，但似乎他们永远不会退出。 parent 等待他们结束，但它从未发生过。谁能告诉我我做错了什么？

<?php
for ($i=1; $i<=5; $i++) {
    $pid = pcntl_fork();

    if ($pid == -1) {
        die("Error Creating subprocess ".$i);
        exit(-1);
    }
    else if (!$pid) {

        switch ($i) {
            case 1:
                // Child 1
                error_log("I\'m the child number ".$i." PID: ".getmypid()."\n", 3, "/var/log/php_errors.log");
                //Doing some stuff
                exit;
            case 2:
                // Child 2
                error_log("I\'m the child number ".$i." PID: ".getmypid()."\n", 3, "/var/log/php_errors.log");
                //Doing some stuff
                exit;
            case 3:
                // Child 3
                error_log("I\'m the child number ".$i." PID: ".getmypid()."\n", 3, "/var/log/php_errors.log");
                //Doing some stuff
                exit;
            case 4:
                // Child 4
                error_log("I\'m the child number ".$i." PID: ".getmypid()."\n", 3, "/var/log/php_errors.log");
                //Doing some stuff
                exit;
            case 5:
                // Child 5
               error_log("I\'m the child number ".$i." PID: ".getmypid()."\n", 3, "/var/log/php_errors.log");
                //Doing some stuff
                exit;
            default:
                break;
        }
    }
    else {
        $pids[] = $pid;
    }
}

error_log("Luke, I\'m your father. PID: ".getmypid()."\n", 3, "/var/log/php_errors.log");
foreach ($pids as $key => $child) {
    $res = pcntl_waitpid($child, $status);
    //Check if this child has exited normally
    if (pcntl_wifexited($status))
        error_log("Child ".$child." has ended\n", 3, "/var/log/php_errors.log");
    else
        error_log("Child ".$child." is zombie\n", 3, "/var/log/php_errors.log");

    if($res == -1 || $res > 0)
        unset($pids[$key]);
}
?>

Answer 1

<?php
for ($i=1; $i<=5; $i++) {
    $pid = pcntl_fork();

    if ($pid == -1) {
        die("Error Creating subprocess ".$i);
        exit(-1);
    }
    else if (!$pid) {

        switch ($i) {
            case 1:
                // Child 1
                error_log("I\'m the child number ".$i." PID: ".getmypid()."\n", 3, "/var/log/php_errors.log");
                //Doing some stuff
                exit;
            case 2:
                // Child 2
                error_log("I\'m the child number ".$i." PID: ".getmypid()."\n", 3, "/var/log/php_errors.log");
                //Doing some stuff
                exit;
            case 3:
                // Child 3
                error_log("I\'m the child number ".$i." PID: ".getmypid()."\n", 3, "/var/log/php_errors.log");
                //Doing some stuff
                exit;
            case 4:
                // Child 4
                error_log("I\'m the child number ".$i." PID: ".getmypid()."\n", 3, "/var/log/php_errors.log");
                //Doing some stuff
                exit;
            case 5:
                // Child 5
               error_log("I\'m the child number ".$i." PID: ".getmypid()."\n", 3, "/var/log/php_errors.log");
                //Doing some stuff
                exit;
            default:
                break;
        }
    }
    else {
        $pids[$pid] = $pid;
    }
}

while (!empty($pids)) {
  if ($child = pcntl_wait($status, WNOHANG)) {
    if (pcntl_wifexited($status))
        error_log("Child ".$child." has ended\n", 3, "/var/log/php_errors.log");
    else
        error_log("Child ".$child." is zombie\n", 3, "/var/log/php_errors.log");
    unset($pids[$child]);    
  } else
    usleep(100);
}

不要忘记更改 $pids[] = $pid;到 $pids[$pid] = $pid; :o) 或选择更好的方式从退出的数组中弹出。