3v4l.org

run code in 300+ PHP versions simultaneously
<?php $a = 1; // Your case function b() { $a = 4; return true; } // Passing by reference function c(&$d) { $d = 5; return true; } // Using return function d($d) { $d = 6; return $d; } b(); var_dump($a); c($a); var_dump($a); $a = d($a); var_dump($a);
Output for 7.1.0 - 7.1.20, 7.2.0 - 7.2.33, 7.3.16 - 7.3.33, 7.4.0 - 7.4.33, 8.0.0 - 8.0.30, 8.1.0 - 8.1.33, 8.2.0 - 8.2.29, 8.3.0 - 8.3.25, 8.4.1 - 8.4.12
int(1) int(5) int(6)

preferences:
145.33 ms | 407 KiB | 5 Q