- var_dump: documentation ( source)
- json_last_error: documentation ( source)
- json_encode: documentation ( source)
<?php
function is_cyclic(array &$array) {
json_encode($array);
return json_last_error() === JSON_ERROR_RECURSION;
}
$array = [1, [2, 3]];
$array[1][1] = &$array;
var_dump(is_cyclic($array));