3v4l.org

run code in 150+ php & hhvm versions
Bugs & Features
<?php error_reporting( -1 ); #ini_set('display_errors', '1'); set_error_handler('my_error_handler'); $global_last_undefined_variable = false; function my_error_handler($severity, $message, $filename, $lineno) { global $global_last_undefined_variable; if ( $severity == E_NOTICE ) { if ( preg_match( '/^Undefined variable: (.*?)$/', $message, $matches ) ) { $global_last_undefined_variable = $matches[1]; } } return false; } function is_undefined( $var ) { global $global_last_undefined_variable; $result = $global_last_undefined_variable==$var; if ( $result ) $global_last_undefined_variable = false; return $result; } $last_notice = false; $a = null; // $b - undefined if ( $a===null && is_undefined( 'a' ) ) echo "a is undefined\n"; else echo "a is defined\n"; if ( $b===null && is_undefined( 'b' ) ) echo "b is undefined\n"; else echo "b is defined\n";
Output for 5.0.4 - 5.6.28, hhvm-3.10.0 - 3.12.0, 7.0.0 - 7.1.0
a is defined Notice: Undefined variable: b in /in/fY96G on line 44 b is undefined
Output for 4.3.10 - 4.4.9, 5.0.3
a is defined Notice: Undefined variable: b in /in/fY96G on line 44 b is defined
Output for 5.0.0 - 5.0.2
a is defined Notice: Undefined variable:  in /in/fY96G on line 44 b is defined
Output for 4.3.9
a is defined Notice: Undefined variable: � in /in/fY96G on line 44 b is defined
Output for 4.3.8
a is defined Notice: Undefined variable: � in /in/fY96G on line 44 b is defined
Output for 4.3.7
a is defined Notice: Undefined variable: q in /in/fY96G on line 44 b is defined
Output for 4.3.0 - 4.3.6
a is defined b is defined