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<?php $auth = false; $s = serialize($auth); echo $s; echo "\n"; echo strrev($s); setcookie("auth", $s); echo $_COOKIE["auth"]; echo "\n"; echo $auth; ?>
Output for 8.0.0 - 8.0.30, 8.1.0 - 8.1.28, 8.2.0 - 8.2.18, 8.3.0 - 8.3.6
b:0; ;0:b Warning: Cannot modify header information - headers already sent by (output started at /in/6ItmL:5) in /in/6ItmL on line 10 Warning: Undefined array key "auth" in /in/6ItmL on line 11
Output for 5.3.0 - 5.3.29, 5.4.0 - 5.4.45, 5.5.0 - 5.5.38, 5.6.0 - 5.6.38, 7.0.0 - 7.0.33, 7.1.0 - 7.1.33, 7.2.0 - 7.2.33, 7.3.0 - 7.3.31, 7.4.0 - 7.4.33
b:0; ;0:b Warning: Cannot modify header information - headers already sent by (output started at /in/6ItmL:5) in /in/6ItmL on line 10 Notice: Undefined index: auth in /in/6ItmL on line 11
Output for 7.3.32 - 7.3.33
b:0; ;0:b Warning: Cannot modify header information - headers already sent by (output started at /in/6ItmL:5) in /in/6ItmL on line 10
Output for 5.2.3 - 5.2.17
b:0; ;0:b Warning: Cannot modify header information - headers already sent by (output started at /in/6ItmL:5) in /in/6ItmL on line 10 Notice: Undefined index: auth in /in/6ItmL on line 11
Output for 4.3.0 - 4.3.11, 4.4.0 - 4.4.9, 5.0.0 - 5.0.5, 5.1.0 - 5.1.6, 5.2.0 - 5.2.2
b:0; ;0:b Notice: Undefined index: auth in /in/6ItmL on line 11

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