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Selected

finalclass
final class Selected

Which select() case fired, and with what.

Example

use Async\SelectCase;
use function Async\async;
use function Async\channel;
use function Async\delay;
use function Async\select;
use function Async\selectNow;
use function Async\selectWithin;
use function Async\spawn;

async(function () {
    $fast = channel();
    $slow = channel();

    spawn(function () use ($fast) { delay(0.01); $fast->send("from fast"); });
    spawn(function () use ($slow) { delay(0.05); $slow->send("from slow"); });

    // A bare channel is shorthand for a receive case.
    $r = select([$slow, $fast]);
    echo "case {$r->index}: {$r->value}\n";

    // Nothing is ready right now.
    var_dump(selectNow([$fast]));

    // A deadline: null when it expires first.
    var_dump(selectWithin(0.01, [$fast]));

    // The other value is still on its way.
    $r = select([$slow]);
    echo $r->value, "\n";

    // A send arm completes when a receiver (or buffer space) is available.
    $out = channel(1);
    $r = select([SelectCase::send($out, 7)]);
    echo $r->isSend ? "sent " : "received ", $out->recv(), "\n";
});

Output

case 1: from fast
NULL
NULL
from slow
sent 7

See also: select

Methods

__construct()Build a select result.

__construct()#source

function __construct(
    public int $index,
    public mixed $value,
    public bool $ok,
    public ?Channel $channel,
    public bool $isSend
)

Build a select result.

Parameters

$index int
position of the winning case
$value mixed
received value, null for a send case
$ok bool
false when the channel was closed
$channel ?Channel
the channel that completed
$isSend bool
whether the winning case was a send

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