3v4l.org

run code in 300+ PHP versions simultaneously
<?php $arr = array('key' => 'value'); //array_map(function($k, $v){var_dump($k, $v);}, array_keys($arr), $arr); array_map(function($a){ var_dump(key($a)); }, &$arr);
Output for 5.4.0 - 5.4.31
Fatal error: Call-time pass-by-reference has been removed in /in/WkVqc on line 8
Process exited with code 255.
Output for 5.3.0 - 5.3.29
Deprecated: Call-time pass-by-reference has been deprecated in /in/WkVqc on line 8 Warning: key() expects parameter 1 to be array, string given in /in/WkVqc on line 7 NULL
Output for 4.4.2 - 4.4.9, 5.1.0 - 5.1.6, 5.2.0 - 5.2.17
Parse error: syntax error, unexpected T_FUNCTION, expecting ')' in /in/WkVqc on line 5
Process exited with code 255.
Output for 4.3.0 - 4.3.1, 4.3.5 - 4.3.11, 4.4.0 - 4.4.1, 5.0.0 - 5.0.5
Parse error: parse error, unexpected T_FUNCTION, expecting ')' in /in/WkVqc on line 5
Process exited with code 255.
Output for 4.3.2 - 4.3.4
Parse error: parse error, expecting `')'' in /in/WkVqc on line 5
Process exited with code 255.
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210.73 ms | 1394 KiB | 122 Q