PHP cURL을 사용하여 HTTP POST 요청을 보내는 방법은 무엇입니까?

// Initialize a cURL handle
$ch = curl_init();

// Set the URL to post to
curl_setopt($ch, CURLOPT_URL, "http://www.example.com/tester.phtml");

// Enable POST method
curl_setopt($ch, CURLOPT_POST, true);

// Set the POST fields
$data = array('username' => 'user1', 'password' => 'passuser1', 'gender' => 1);
$post_fields = http_build_query($data);
curl_setopt($ch, CURLOPT_POSTFIELDS, $post_fields);

// Receive server response
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
$server_output = curl_exec($ch);

// Close the cURL handle
curl_close($ch);

// Process the response
if ($server_output == "OK") {
    // Handle successful response
} else {
    // Handle error
}