3v4l.org

run code in 300+ PHP versions simultaneously
<?php // The original function function a($i){$e=microtime(1)+$i;while(microtime(1)<$e);} // Use 'for' instead of 'while' function b($i){for($e=microtime(1)+$i;microtime(1)<$e;);} // Extract 'microtime' into a variable // Requires error_reporting(0) to suppress the "PHP Notice: Use of undefined constant microtime" // Use '-d error_reporting=0' in the command line function c($i){for($f=microtime,$e=$f(1)+$i;$f(1)<$e;);} // Squeeze the initialization of $f into its first use // PHP 7 only; it doesn't compile on older versions function d($i){for($e=($f=microtime)(1)+$i;$f(1)<$e;);}

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