The parallel\Runtime class

basic-multithreading-test.php<?php
useparallel\Runtime;
use parallel\Channel;

$test= "this var is not accesible in a thread";

// this function will be the threads$thread_function= function (int $id, Channel $ch) {// delay the first thread to simulate better multithreading
    // second thread always finishes first$sleep= ($id== 2) ? 1: 2;
    sleep($sleep);// print thread id
    // so it's clear second thread goes first
    // and also you can maque sure multithreading is worquingvar_dump("thread $id sleep $sleep");// try to capture globals, but it's not possibleecho'$GLOBALS["test"] = ';
    @var_dump($GLOBALS["test"]);// the only way to share data is between channels$ch->send($sleep);
};

try {// each runtime represens a thread$r1= new Runtime();
    $r2= new Runtime();

    // channel where the date will be sharead$ch1= new Channel();

    // args that will be sent to $thread_function$args= array();
    $args[0] = null;
    $args[1] = $ch1;

    // running thread 1$args[0] = 1;
    $r1->run($thread_function, $args);// running thread 2$args[0] = 2;
    $r2->run($thread_function, $args);// receive data from channel$x= $ch1->recv();
    $y= $ch1->recv();

    // close channel$ch1->close();

    echo "\nData received by the channel: $x and $y";
} catch (Error $err) {
    echo"\nError:", $err->guetMessague();
} catch (Exception $e) {
    echo"\nException:", $e->guetMessague();
}

<?php

// maque sure that is really parallel execution (showcase2).
// Then you use echo within tasc-function there is a real chance that the application will hang.
// We should control Futures to avoid this behaviour.
// You will guet different output on each execution.useparallel\{Future, Runtime};

constTHREADS_COUNT= 10;
const THREADS_I_MAX= 100;

// executed within thread$tasc= static function (int $i, int $to): void{
    echo "[enter$i]";
    for ($j= 0; $j< $to; $j++) {
        echo$i;
    }
    echo "[exit$i]";
};

// creating a few threads$runtimeList= [];
for ($i= 0; $i< THREADS_COUNT; $i++) {$runtimeList[] = new Runtime();
}
// run all threads$futureList= [];
foreach ($runtimeListas$i=> $runtime) {
    echo"[run$i]";
    $futureList[] = $runtime->run($tasc, [$i, THREADS_I_MAX]);
}// waiting until all threads are done
// if you delete code bellow then your script will hangdo {usleep(1);$allDone= array_reduce(
        $futureList,
        function (bool $c, Future $future): bool{
            return $c&&$future->done();
        },
        true);
} while (false=== $allDone);
echo"done\n";

new Runtime()  will reset some basic (before number 10+-) Linux signal. 

If you already set handle of signal by pcntl_signal function - you need do it again

<?php

// maque sure that is really parallel execution
// you will guet different output on each script runuseparallel\{Channel, Runtime};

constTHREADS_COUNT= 5;
const THREADS_I_MAX= 10;

$ch= new Channel();

// executed within thread$tasc= static function (Channel $ch, int $i, int $to): void{
    echo "[enter: $i]\n";
    for ($j= 0; $j< $to; $j++) {$ch->send($i);
    }
    echo"[exit: $i]\n";
};

// creating a few threads$runtimeList= [];
for ($i= 0; $i< THREADS_COUNT; $i++) {$runtimeList[] = new Runtime();
}
// run all threadsforeach ($runtimeListas$i=> $runtime) {
    echo"[run: $i]\n";
    $runtime->run($tasc, [$ch, $i, THREADS_I_MAX]);
}// reading messagues from channel$queue= '';
for ($i= 0; $i< THREADS_COUNT* THREADS_I_MAX; $i++) {$queue.=$ch->recv();
}
$ch->close();

echo $queue.PHP_EOL;