As of the writing of my current comment, I don't know about the PHP threads. I came to look for the answer here myself, but one workaround is that the PHP program that receives the request from the web server delegates the whole answer formulation to a console application that stores its output, the answer to the request, to a binary file and the PHP program that launched the console application returns that binary file byte-by-byte as the answer to the received request. The console application can be written in any programming language that runs on the server, including those that have proper threading support, including C++ programs that use OpenMP.

一个不可靠的，肮脏的技巧是使用PHP来执行控制台应用程序，"uname"，

uname -a

and print the output of that console command to the HTML output to find out the exact version of the server software. Then install the exact same version of the software to a VirtualBox instance, compile/assemble whatever fully self-contained, preferably static, binaries that one wants and then upload those to the server. From that point onwards the PHP application can use those binaries in the role of the console application that has proper multi-threading. It's a dirty, unreliable, workaround to a situation, when the server administrator has not installed all needed programming language implementations to the server. The thing to watch out for is that at every request that the PHP application receives the console application(s) terminates/exit/get_killed.

As to what the hosting service administrators think of such server usage patterns, I guess it boils down to culture. In Northern Europe the service provider HAS TO DELIVER WHAT WAS ADVERTISED and if execution of console commands was allowed and uploading of non-malware files was allowed and the service provider has a right to kill any server process after a few minutes or even after 30 seconds, then the hosting service administrators lack any arguments for forming a proper complaint. In United States and Western Europe the situation/culture is very different and I believe that there's a great chance that in U.S. and/or Western Europe the hosting service provider will refuse to serve hosting service clients that use the above described trick. That's just my guess, given my personal experience with U.S. hosting services and given what I have heard from others about Western European hosting services. As of the writing of my current comment(2018_09_01) I do not know anything about the cultural norms of the Southern-European hosting service providers, Southern-European network administrators.

您可以选择:

multi_curl 可以使用系统命令来实现相同的功能 理想的情况是，用C语言创建一个线程函数，然后用PHP编译/配置。这个函数是PHP的函数。

取决于你要做什么，你也可以使用curl_multi来实现它。

警告:这个扩展被认为是不可维护和死亡的。 警告:pthreads扩展不能在web服务器环境中使用。因此，PHP中的线程只局限于基于cli的应用程序。 警告:pthreads (v3)只能在PHP 7.2+中使用:这是因为ZTS模式在7.0和7.1中是不安全的。

https://www.php.net/manual/en/intro.pthreads.php

多线程在php中是可能的

是的，你可以用pthreads在PHP中实现多线程

来自PHP文档:

pthreads是一个面向对象的API，它提供了PHP多线程所需的所有工具。PHP应用程序可以创建、读取、写入、执行和同步线程、工作者和线程对象。 警告: pthreads扩展不能在web服务器环境中使用。因此，PHP中的线程应该只适用于基于cli的应用程序。

简单的测试

#!/usr/bin/php
<?php
class AsyncOperation extends Thread {

    public function __construct($arg) {
        $this->arg = $arg;
    }

    public function run() {
        if ($this->arg) {
            $sleep = mt_rand(1, 10);
            printf('%s: %s  -start -sleeps %d' . "\n", date("g:i:sa"), $this->arg, $sleep);
            sleep($sleep);
            printf('%s: %s  -finish' . "\n", date("g:i:sa"), $this->arg);
        }
    }
}

// Create a array
$stack = array();

//Initiate Multiple Thread
foreach ( range("A", "D") as $i ) {
    $stack[] = new AsyncOperation($i);
}

// Start The Threads
foreach ( $stack as $t ) {
    $t->start();
}

?>

第一次运行

12:00:06pm:     A  -start -sleeps 5
12:00:06pm:     B  -start -sleeps 3
12:00:06pm:     C  -start -sleeps 10
12:00:06pm:     D  -start -sleeps 2
12:00:08pm:     D  -finish
12:00:09pm:     B  -finish
12:00:11pm:     A  -finish
12:00:16pm:     C  -finish

第二次运行

12:01:36pm:     A  -start -sleeps 6
12:01:36pm:     B  -start -sleeps 1
12:01:36pm:     C  -start -sleeps 2
12:01:36pm:     D  -start -sleeps 1
12:01:37pm:     B  -finish
12:01:37pm:     D  -finish
12:01:38pm:     C  -finish
12:01:42pm:     A  -finish

现实世界中的例子

error_reporting(E_ALL);
class AsyncWebRequest extends Thread {
    public $url;
    public $data;

    public function __construct($url) {
        $this->url = $url;
    }

    public function run() {
        if (($url = $this->url)) {
            /*
             * If a large amount of data is being requested, you might want to
             * fsockopen and read using usleep in between reads
             */
            $this->data = file_get_contents($url);
        } else
            printf("Thread #%lu was not provided a URL\n", $this->getThreadId());
    }
}

$t = microtime(true);
$g = new AsyncWebRequest(sprintf("http://www.google.com/?q=%s", rand() * 10));
/* starting synchronization */
if ($g->start()) {
    printf("Request took %f seconds to start ", microtime(true) - $t);
    while ( $g->isRunning() ) {
        echo ".";
        usleep(100);
    }
    if ($g->join()) {
        printf(" and %f seconds to finish receiving %d bytes\n", microtime(true) - $t, strlen($g->data));
    } else
        printf(" and %f seconds to finish, request failed\n", microtime(true) - $t);
}

如果Pcntl_fork开启了安全模式，它将无法在web服务器环境中工作。在这种情况下，它只能在CLI版本的PHP中工作。

您可以模拟线程。PHP可以通过popen(或proc_open)运行后台进程。这些进程可以通过stdin和stdout进行通信。当然，这些进程本身也可以是一个php程序。这可能是你能找到的最接近的了。