Question

I have 2 simple PHP files:

test.php

<?php
$a=10;
require "use.php?c=$a";
?>

use.php:

<?php
$test=$_GET['c'];
echo $test;
?>

But it returns nothing.

What is wrong?

Answer 1

include() and require() do not make HTTP requests unless you supply a full URL, they work on the local file system. $_GET and friends use URL parameters when they are populated. You code should not work, because you are trying to require() a file called use.php?c=$a, not a file called use.php passing the value $a to the parameter c, which is what you want.

This will work:

test.php

<?php
$a=10;
require "use.php";
?>

use.php

<?php
echo $a;
?>

If you are getting no output, you should enable error reporting:

error_reporting(-1);
ini_set('display_errors',1);