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<?php define('CONSTANT', 1); define('_CONSTANT', 0); define('EMPTY', ''); var_dump(CONSTANT); $a = '5'; if (!empty($a)) { if (!(boolean) _CONSTANT) { echo 1; } } else if (constant('CONSTANT') == 1) { echo 2; }
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, 5.3.0 - 5.3.29, 5.4.0 - 5.4.45, 5.5.0 - 5.5.38, 5.6.0 - 5.6.40, 7.0.0 - 7.0.33, 7.1.0 - 7.1.33, 7.2.0 - 7.2.33, 7.3.0 - 7.3.33, 7.4.0 - 7.4.33, 8.0.0 - 8.0.30, 8.1.0 - 8.1.28, 8.2.0 - 8.2.18, 8.3.0 - 8.3.6
int(1) 1

preferences:
328.6 ms | 406 KiB | 456 Q