Message: Call to undefined function curl_exec() in php

Question

Call to undefined function curl_exec() in php

$ch = curl_init();
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
curl_setopt($ch, CURLOPT_URL, $url);
curl_setopt($ch, CURLOPT_PROXY, 'http://10.59.82.2:8080');
curl_setopt($ch, CURLOPT_HTTPHEADER, $header);
curl_setopt($ch, CURLOPT_POSTFIELDS, $post );   
curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false);
$datas = curl_exec($ch);
$error = curl_error($ch);
$status = curl_getinfo($ch, CURLINFO_HTTP_CODE);
curl_close($ch);