Bug #78073 [NEW]: echo fmod(25, 0.2); // 0.2, must be 0

From: e dot grinec at gmail dot com Operating system: Windows 10 x64 PHP version: 7.3.5 Package: *Math Functions Bug Type: Bug Bug description:echo fmod(25, 0.2); // 0.2, must be 0 Description: ------------ --- From manual page: https://php.net/function.fmod --- PHP 5.2.x through PHP 7.3.2 still the same problem. Code: <?php echo fmod(-25, 0.2); // -0.2, should be 0 echo -25 - floor(-25/0.2) * 0.2; // 0, as it should be ?> Default installation of OSPanel (OpenServer 5.2.2) with default configuration of php.ini and etc in it. Documentation says: "Returns the floating point remainder of dividing the dividend (x) by the divisor (y). The remainder (r) is defined as: x = i * y + r, for some integer i. If y is non-zero, r has the same sign as x and a magnitude LESS than the magnitude of y." But r magnitude EQUAL to y. Solution: function fmod($x, $y){return echo $x - floor($x/$y) * $y;} Test script: --------------- <?php echo var_dump(fmod(21, 0.2) == 0); // bool(false) echo var_dump(fmod(1, 0.1) == 0); // bool(false) echo fmod(1, 0.1); // 0.1 echo fmod(1, 0.2); // 0.2 Expected result: ---------------- <?php echo var_dump(fmod(21, 0.2) == 0); // bool(true) echo var_dump(fmod(1, 0.1) == 0); // bool(true) echo fmod(1, 0.1); // 0 echo fmod(1, 0.2); // 0 Actual result: -------------- bool(false) bool(false) 0.1 0.2 -- Edit bug report at https://bugs.php.net/bug.php?id=78073&edit=1 -- Try a snapshot (PHP 5.4): https://bugs.php.net/fix.php?id=78073&r=trysnapshot54 Try a snapshot (PHP 5.5): https://bugs.php.net/fix.php?id=78073&r=trysnapshot55 Try a snapshot (trunk): https://bugs.php.net/fix.php?id=78073&r=trysnapshottrunk Fixed in SVN: https://bugs.php.net/fix.php?id=78073&r=fixed Fixed in release: https://bugs.php.net/fix.php?id=78073&r=alreadyfixed Need backtrace: https://bugs.php.net/fix.php?id=78073&r=needtrace Need Reproduce Script: https://bugs.php.net/fix.php?id=78073&r=needscript Try newer version: https://bugs.php.net/fix.php?id=78073&r=oldversion Not developer issue: https://bugs.php.net/fix.php?id=78073&r=support Expected behavior: https://bugs.php.net/fix.php?id=78073&r=notwrong Not enough info: https://bugs.php.net/fix.php?id=78073&r=notenoughinfo Submitted twice: https://bugs.php.net/fix.php?id=78073&r=submittedtwice register_globals: https://bugs.php.net/fix.php?id=78073&r=globals PHP 4 support discontinued: https://bugs.php.net/fix.php?id=78073&r=php4 Daylight Savings: https://bugs.php.net/fix.php?id=78073&r=dst IIS Stability: https://bugs.php.net/fix.php?id=78073&r=isapi Install GNU Sed: https://bugs.php.net/fix.php?id=78073&r=gnused Floating point limitations: https://bugs.php.net/fix.php?id=78073&r=float No Zend Extensions: https://bugs.php.net/fix.php?id=78073&r=nozend MySQL Configuration Error: https://bugs.php.net/fix.php?id=78073&r=mysqlcfg