Example usage of pcntl_fork

pcntl_fork_example.php

<?php

    class Task {

        private $cb;
        public function __construct(callable $cb) {
            $this->cb = $cb;
        }

        public function start() {
            $pid = pcntl_fork();
            if ($pid == -1) {
                die('could not fork');
            } else if ($pid) {
                return;
                pcntl_wait($status); //Protect against Zombie children
            } else {
                ($this->cb)();
                exit;
            }
        }

    }

    $task1 = new Task(function() {
        for($i = 0; $i <= 100; $i++) {
            echo "\n1: Task: $i";
            usleep(10000);
        }
    });

    $task2 = new Task(function() {
        for($i = 0; $i <= 100; $i++) {
            echo "\n2: Task: $i";
            usleep(20000);
        }
    });

    $task1->start();
    $task2->start();

?>