isset vs empty vs is_null

Question

I\'m trying to write a script that when a user uploads a file and does not enter a name an error is returned. I\'ve tried using is_null, empty, and isset and they all do not

Answer 1

I use strlen to count the number of characters

 if (strlen($_REQUEST['name_input_name']) < 1) {
    $file->error = 'Please Enter a Title';
    return false;
}