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run code in 300+ PHP versions simultaneously
<?php define('DB_USER','root'); echo "DB_USER=$GLOBALS[db_user]";
Output for 8.1.0 - 8.1.27, 8.2.0 - 8.2.17, 8.3.0 - 8.3.4
Warning: Undefined global variable $db_user in /in/iAVfo on line 3 DB_USER=
Output for 8.0.0 - 8.0.30
Warning: Undefined array key "db_user" in /in/iAVfo on line 3 DB_USER=
Output for 5.3.0 - 5.3.29, 5.4.0 - 5.4.45, 5.5.24 - 5.5.35, 5.6.7 - 5.6.28, 7.0.0 - 7.0.20, 7.1.0 - 7.1.25, 7.2.0 - 7.2.33, 7.3.0 - 7.3.31, 7.4.0 - 7.4.33
Notice: Undefined index: db_user in /in/iAVfo on line 3 DB_USER=
Output for 7.3.32 - 7.3.33
DB_USER=
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 - 5.2.17
Notice: Undefined index: db_user in /in/iAVfo on line 3 DB_USER=

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