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run code in 150+ php & hhvm versions
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<?php ob_start(); header("X-WTFIDONTEVEN: true"); if (headers_sent()) { echo "sent"; } else { echo "not sent"; } ob_end_flush();
Output for 5.2.3 - 5.6.28, hhvm-3.10.0 - 3.12.0, 7.0.0 - 7.1.0
not sent
Output for 4.3.0 - 5.2.2
sent