note 110824 added to function.fmod

Note that fmod is NOT equivalent to this basic function: function modulo($a, $b) { return $a - $b * floor($a / $b); } because fmod() will return a value with the same sign as $a. In other words the floor() function is not correct as it rounds towards -INF instead of towards zero. To emulate fmod($a, $b) the correct way is: function fmod($a, $b) { return $a - $b * (($b < 0) ? ceil($a / $b) : floor($a / $b))); } Note that both functions will throw a DIVISION BY ZERO if $b is null. The first function modulo() above is the mathematical function which is useful for working on cyclic structures (such as calender computions or trignonometric functions : - fmod($a, 2*PI) returns a value in [0..2*PI) if $a is positive - fmod($a, 2*PI) returns a value in [-2*PI..0] if $a is negative - modulo($a, 2*PI) returns a value always in [0..2*PI) independantly of the sign of $a ---- Server IP: 69.147.83.199 Probable Submitter: 72.52.91.2 (proxied: 89.2.191.39) ---- Manual Page -- http://php.net/manual/en/function.fmod.php Edit -- https://master.php.net/note/edit/110824 Del: integrated -- https://master.php.net/note/delete/110824/integrated Del: useless -- https://master.php.net/note/delete/110824/useless Del: bad code -- https://master.php.net/note/delete/110824/bad+code Del: spam -- https://master.php.net/note/delete/110824/spam Del: non-english -- https://master.php.net/note/delete/110824/non-english Del: in docs -- https://master.php.net/note/delete/110824/in+docs Del: other reasons-- https://master.php.net/note/delete/110824 Reject -- https://master.php.net/note/reject/110824 Search -- https://master.php.net/manage/user-notes.php