3v4l.org

run code in 150+ php & hhvm versions
Bugs & Features
<?php $a = array(1, 2); $b = array(&$a); $a[] = $b; var_dump(json_encode($a), JSON_ERROR_SYNTAX); echo json_last_error();
based on FV0GO
Output for 5.5.0 - 7.1.0
bool(false) int(4) 6
Output for 5.3.0 - 5.4.45
Warning: json_encode(): recursion detected in /in/htQWf on line 7 string(18) "[1,2,[[1,2,null]]]" int(4) 0
Output for 5.2.0 - 5.2.17
Warning: json_encode(): recursion detected in /in/htQWf on line 7 Notice: Use of undefined constant JSON_ERROR_SYNTAX - assumed 'JSON_ERROR_SYNTAX' in /in/htQWf on line 7 string(18) "[1,2,[[1,2,null]]]" string(17) "JSON_ERROR_SYNTAX" Fatal error: Call to undefined function json_last_error() in /in/htQWf on line 8
Process exited with code 255.
Output for 5.0.0 - 5.1.6
Fatal error: Call to undefined function json_encode() in /in/htQWf on line 7
Process exited with code 255.
Output for 4.4.5 - 4.4.9
Fatal error: Call to undefined function: json_encode() in /in/htQWf on line 7
Process exited with code 255.
Output for 4.3.2 - 4.4.4
Fatal error: Call to undefined function: json_encode() in /in/htQWf on line 7
Process exited with code 255.
Output for 4.3.0 - 4.3.1
Fatal error: Call to undefined function: json_encode() in /in/htQWf on line 7