Documentation

Learn how to use TrueAsync for building concurrent PHP applications.

Channel::isEmpty

(PHP 8.6+, True Async 1.0)

public Channel::isEmpty(): bool

Checks whether the channel buffer is empty (no values available for receiving).

For a rendezvous channel (capacity = 0), this always returns true, since data is transferred directly without buffering.

Return values

true — the buffer is empty. false — the buffer contains values.

Examples

Example #1 Checking for available data

<?php

use Async\Channel;

$channel = new Channel(5);

echo $channel->isEmpty() ? "empty" : "has data"; // "empty"

$channel->send(42);

echo $channel->isEmpty() ? "empty" : "has data"; // "has data"

Example #2 Batch data processing

<?php

use Async\Channel;

$channel = new Channel(100);

spawn(function() use ($channel) {
    while (!$channel->isClosed() || !$channel->isEmpty()) {
        if ($channel->isEmpty()) {
            delay(50); // wait for data to arrive
            continue;
        }

        $batch = [];
        while (!$channel->isEmpty() && count($batch) < 10) {
            $batch[] = $channel->recv();
        }

        processBatch($batch);
    }
});

See also