CURL how not to wait for a response?

Question

PHP

There is a simple code:

$v1 = microtime(true);
$main = curl_init('http://site.com/test.php');
curl_setopt($main, CURLOPT_RETURNTRANSFER, 1);
curl_setopt($main, CURLOPT_USERAGENT, 'Opera/9.80');
curl_setopt($main, CURLOPT_FOLLOWLOCATION, 1);
curl_exec($main);

$v2 = microtime(true);
echo $v2 - $v1.'<br>';
echo 'ok';

The landing page has the following http://site.com/test.phpcode:

sleep(3);
echo 'цель';

As a result, the first script always waits for the second one to complete and send a response, i.e. its operating time is at least 3 seconds.
How can I send a curl request and not wait for a response, but immediately show ok in the first script?

Answer 1

https://stackoverflow.com/a/962920