3v4l.org

run code in 300+ PHP versions simultaneously
<?php //PHPの関数 //様々な関数 $a[] = "000"; //empty関数 /*以下の場合にTRUE ・空白の数値 ・NULLやFALSE ・変数が定義されただけの状態 ・文字列の半角の0 ・配列、数値の0 */ print a; echo empty($a).PHP_EOL;
based on NU2CB
Output for 8.0.0 - 8.0.1
Fatal error: Uncaught Error: Undefined constant "a" in /in/6WcGf:15 Stack trace: #0 {main} thrown in /in/6WcGf on line 15
Process exited with code 255.
Output for 7.3.0 - 7.3.26, 7.4.0 - 7.4.14
Warning: Use of undefined constant a - assumed 'a' (this will throw an Error in a future version of PHP) in /in/6WcGf on line 15 a