the file_put_contents function does not work ... from php

Hello, good night, I would like to know why I do not believe the file gente.txt ? I was told that it may be permissions to create or edit files, but how would that be in wampserver? Thank you very much here I put the code.

$fichero = 'gente.txt';
// La nueva persona a añadir al fichero
$persona = "John Smith\n";
file_put_contents($fichero, $persona, FILE_APPEND | LOCK_EX);