- var_dump: documentation ( source)
- fputcsv: documentation ( source)
- fopen: documentation ( source)
<?php
var_dump((new ReflectionFunction('fputcsv'))->getNumberOfParameters());
$fp = fopen('php://temp', 'r+');
$res = fputcsv($fp, [1, 2, 3], ',', '"', '\\');
var_dump($res);