<?php

function requestUrl($url)
{
    $ch = curl_init();
    curl_setopt($ch, CURLOPT_URL, $url);
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
    $output = curl_exec($ch);
    curl_close($ch);
    echo md5($output)."\n";
}

$urls = [
    "http://php.net", // Will work fine
    "https://stackoverflow.com/", // Will fail
];

// First, request an HTTPS url, required for the bug to occur
requestUrl("https://facebook.com");

foreach ($urls as $url) {
    $pid = pcntl_fork();
    if ($pid == -1) {
        throw new \Exception('Could not fork');
    } else if ($pid) {
        // Parent process
        pcntl_waitpid($pid, $status);

        print_r([
            "URL" => $url,
            "Successful Exit" => pcntl_wifexited($status) ? "Yes" : "No",
            "Exit Code" => pcntl_wexitstatus($status)
        ]);

        echo "\n";
    } else {
        // Child process
        requestUrl($url);
        exit(0);
    }
}