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<?php $c = array_filter(get_defined_constants(), function ($constantName) { return in_array($constantName, ['TRUE', 'FALSE', 'NULL'], true); }, ARRAY_FILTER_USE_KEY); var_dump($c);
Output for 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 - 8.2.19, 8.3.0 - 8.3.7
array(3) { ["TRUE"]=> bool(true) ["FALSE"]=> bool(false) ["NULL"]=> NULL }
preferences:
124.61 ms | 403 KiB | 214 Q