Non Blocking Channel Operations in PHP

Our first program demonstrates non-blocking channel operations. Here’s the full source code:

<?php

function main() {
    $messages = new SplQueue();
    $signals = new SplQueue();

    // Here's a non-blocking receive. If a value is
    // available in $messages then it will be retrieved,
    // otherwise it will immediately take the default case.
    if (!$messages->isEmpty()) {
        $msg = $messages->dequeue();
        echo "received message $msg\n";
    } else {
        echo "no message received\n";
    }

    // A non-blocking send works similarly. Here $msg
    // cannot be sent to the $messages queue, because
    // the queue is empty and there is no receiver.
    // Therefore the default case is selected.
    $msg = "hi";
    if ($messages->count() < 5) {  // Assume a max size of 5 for the queue
        $messages->enqueue($msg);
        echo "sent message $msg\n";
    } else {
        echo "no message sent\n";
    }

    // We can use multiple conditions to implement a multi-way
    // non-blocking select. Here we attempt non-blocking receives
    // on both $messages and $signals.
    if (!$messages->isEmpty()) {
        $msg = $messages->dequeue();
        echo "received message $msg\n";
    } elseif (!$signals->isEmpty()) {
        $sig = $signals->dequeue();
        echo "received signal $sig\n";
    } else {
        echo "no activity\n";
    }
}

main();

To run the program, save it as non_blocking_operations.php and use php:

$ php non_blocking_operations.php
no message received
sent message hi
no activity

In this PHP translation, we’ve used SplQueue to simulate channels. The non-blocking operations are implemented using conditional statements to check if the queues are empty or full before attempting to dequeue or enqueue.

Note that PHP doesn’t have built-in support for concurrent programming like Go does, so this example is a simplified simulation of the concept. In a real-world scenario, you might need to use extensions like pthreads or pcntl for true concurrency in PHP.

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Non Blocking Channel Operations in PHP