PHP Manual: Poll connections

Description

Object-oriented style

public static intfalse mysqli::poll(
    arraynull &$read,
    arraynull &$error,
    array &$reject,
    int $seconds,
    int $microseconds = 0
)

Procedural style

intfalse mysqli_poll(
    arraynull &$read,
    arraynull &$error,
    array &$reject,
    int $seconds,
    int $microseconds = 0
)

Poll connections. The method can be used as static.

Note:
Available only with mysqlnd.

Parameters

read: List of connections to check for outstanding results that can be read.
error: List of connections on which an error occurred, for example, query failure or lost connection.
reject: List of connections rejected because no asynchronous query has been run on for which the function could poll results.
seconds: Maximum number of seconds to wait, must be non-negative.
microseconds: Maximum number of microseconds to wait, must be non-negative.

Return Values

Returns number of ready connections upon success, false otherwise.

Errors/Exceptions

A ValueError is thrown when neither the read nor error arguments are passed.

Changelog

Version	Description
8.3.0	Now throws a ValueError exception when neither the `read` nor `error` arguments are passed.

Examples

Example #1 A mysqli_poll example

<?php
$link1 = mysqli_connect();
$link1->query("SELECT 'test'", MYSQLI_ASYNC);
$all_links = array($link1);
$processed = 0;
do {
    $links = $errors = $reject = array();
    foreach ($all_links as $link) {
        $links[] = $errors[] = $reject[] = $link;
    }
    if (!mysqli_poll($links, $errors, $reject, 1)) {
        continue;
    }
    foreach ($links as $link) {
        if ($result = $link->reap_async_query()) {
            print_r($result->fetch_row());
            if (is_object($result))
                mysqli_free_result($result);
        } else die(sprintf("MySQLi Error: %s", mysqli_error($link)));
        $processed++;
    }
} while ($processed < count($all_links));
?>

The above example will output:

Array
(
    [0] => test
)

mysqli::poll

mysqli_poll