PHP mysqli: poll() function
mysqli_poll function / mysqli::poll
The mysqli_poll function / mysqli::poll — Poll connections
Syntax:
Object oriented style
public static int mysqli::poll ( array &$read , array &$error , array &$reject , int $sec [, int $usec ] )
Procedural style
int mysqli_poll ( array &$read , array &$error , array &$reject , int $sec [, int $usec ] )
Parameter:
Name | Description |
---|---|
read | List of connections to check for outstanding results that can be read. |
error | List of connections on which an error occured, 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. |
sec | Maximum number of seconds to wait, must be non-negative. |
usec | Maximum number of seconds to wait, must be non-negative. |
Usage: Procedural style
mysqli_poll(connection);
Parameter:
Name | Description | Required/Optional |
---|---|---|
connection | Specifies the MySQL connection to use | Required |
Return value:
Returns number of ready connections upon success, FALSE otherwise.
Version: PHP 5, PHP 7
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));
?>
See also
PHP: Tips of the Day
var_export(): var_export() dumps a PHP parseable representation of the item.
You can pass true as the second parameter to return the contents into a variable.
Example:
<?php $myarray = [ "PHP", "Tips" ]; $mystring = "PHP Tips"; $myint = 28; var_export($myarray); var_export($mystring); var_export($myint); ?>
Output:
array ( 0 => 'PHP', 1 => 'Tips', )'PHP Tips'28
To put the content into a variable, you can do this:
$array_export = var_export($myarray, true); $string_export = var_export($mystring, true); $int_export = var_export($myint, 1); // any `Truthy` value
After that, you can output it like this:
printf('$myarray = %s; %s', $array_export, PHP_EOL); printf('$mystring = %s; %s', $string_export, PHP_EOL); printf('$myint = %s; %s', $int_export, PHP_EOL);
Example:
<?php $myarray = [ "PHP", "Tips" ]; $mystring = "PHP Tips"; $myint = 28; $array_export = var_export($myarray, true); $string_export = var_export($mystring, true); $int_export = var_export($myint, 1); printf('$myarray = %s; %s', $array_export, PHP_EOL); printf('$mystring = %s; %s', $string_export, PHP_EOL); printf('$myint = %s; %s', $int_export, PHP_EOL); ?>
This will produce the following output:
Output:
$myarray = array ( 0 => 'PHP', 1 => 'Tips', ); $mystring = 'PHP Tips'; $myint = 28;
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