Online PHP editor | refs for HMcFD

@ 2023-01-23T23:22:17Z

<?php

foreach (\DateTimeZone::listIdentifiers(\DateTimeZone::ALL_WITH_BC) as $tz) {
    try {
        new \DateTimeZone($tz);
        
        if (preg_match('{\AEtc/GMT[+-]\d+\z}', $tz)) {
            echo "OK: $tz", PHP_EOL;
        }
    } catch (\Throwable $ex) {
        echo "FAIL: $tz", PHP_EOL;
    }
}