note 108046 added to function.floor

I have this little truncate float function function truncate1 ($num, $digits = 0) { $shift = pow(10 , $digits); return ((floor($num * $shift)) / $shift); } I hit a weird floor() behavior problem recently, it took very long time to debug, see this: $e_num = 25/24; echo $e_num." orig\n"; // get 1.0416666666667 $rnd = round($e_num, 6); echo $rnd." round\n"; // get 1.041667 $trc = truncate1($rnd, 6); echo $trc." truncate\n"; // get 1.041666 !! expected 1.041667 $mul = $rnd * 1000000; echo $mul." multiply\n"; // get 1041667 $flr = floor($mul); echo $flr." floor\n"; // get 1041666, expected 1041667 I think because $rnd is kept as float so it's not precisely 1.041667. So i tested this further $flr1 = floor(1.041667 * 1000000); echo $flr1." floor1\n"; // get 1041666 $flr2 = floor(1041667); echo $flr2." floor2\n"; // get 1041667 So beware of float type !!! ---- Server IP: 124.217.228.174 Probable Submitter: 110.159.131.36 ---- Manual Page -- http://www.php.net/manual/en/function.floor.php Edit -- https://master.php.net/note/edit/108046 Del: integrated -- https://master.php.net/note/delete/108046/integrated Del: useless -- https://master.php.net/note/delete/108046/useless Del: bad code -- https://master.php.net/note/delete/108046/bad+code Del: spam -- https://master.php.net/note/delete/108046/spam Del: non-english -- https://master.php.net/note/delete/108046/non-english Del: in docs -- https://master.php.net/note/delete/108046/in+docs Del: other reasons-- https://master.php.net/note/delete/108046 Reject -- https://master.php.net/note/reject/108046 Search -- https://master.php.net/manage/user-notes.php