3v4l.org

run code in 200+ php & hhvm versions
<?php $foo = new stdClass; $bar = new stdClass; $foo->bar = $bar; $bar->foo = $foo; echo json_encode($foo);
Output for 5.5.0 - 5.6.40, hhvm-3.10.1 - 3.22.0, 7.0.0 - 7.3.3
Output for 5.2.0 - 5.4.45
Warning: json_encode(): recursion detected in /in/5rVEA on line 9 {"bar":{"foo":{"bar":null}}}
Output for 5.0.0 - 5.1.6
Fatal error: Call to undefined function json_encode() in /in/5rVEA on line 9
Process exited with code 255.
Output for 4.4.5 - 4.4.9
Fatal error: Call to undefined function: json_encode() in /in/5rVEA on line 9
Process exited with code 255.
Output for 4.3.2 - 4.4.4
Fatal error: Call to undefined function: json_encode() in /in/5rVEA on line 9
Process exited with code 255.
Output for 4.3.0 - 4.3.1
Fatal error: Call to undefined function: json_encode() in /in/5rVEA on line 9