最简单的cURL代码不会在CURLOPT_URL选项中执行脚本

How can a cURL code be more basic? Yet I can't get it to output - hello cURL! - on the browser. Please help!

<?php
$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, "http://".$_SERVER["HTTP_HOST"]."/ita2/test.php");
curl_exec($ch);
curl_close($ch);
?>

This is the test.php script:

<?php
echo "hello cURL!";
?>