Bug #74925 [NEW]: Mismatching floating values

From: tuepp at gmx dot de Operating system: Windows PHP version: 7.0.21 Package: PHP Language Specification Bug Type: Bug Bug description:Mismatching floating values Description: ------------ Floating number comparison fails for numbers that have to be rounded internal. This bug may be over 10 years old. I've reported it 5 years ago and it is still not fixed. Now I have an example with one instead of 3 lines of code what might be more shoking. I've documented this bug in my final exam 6 years ago and it feeled like I got some extra points for it - so thank you. But now it's really time to fix it! I'm not sure if I'll report it a third time in another 5 years... So go, get it! Test script: --------------- <?php echo (54.83 + 0.01 == 54.84) ? 'ok' : 'fail'; //fail echo "<br>\n"; echo ((3 * 202.3) == 606.9) ? 'ok' : 'fail'; //fail echo "<br>\n"; for($v = -1; $v < 0; $v += 0.2){ echo "$v; "; // -1; -0.8; -0.6; -0.4; -0.2; -5.5511151231258E-17; } Expected result: ---------------- ok ok -1; -0.8; -0.6; -0.4; -0.2 Actual result: -------------- fail fail -1; -0.8; -0.6; -0.4; -0.2; -5.5511151231258E-17; -- Edit bug report at https://bugs.php.net/bug.php?id=74925&edit=1 -- Try a snapshot (PHP 5.4): https://bugs.php.net/fix.php?id=74925&r=trysnapshot54 Try a snapshot (PHP 5.5): https://bugs.php.net/fix.php?id=74925&r=trysnapshot55 Try a snapshot (trunk): https://bugs.php.net/fix.php?id=74925&r=trysnapshottrunk Fixed in SVN: https://bugs.php.net/fix.php?id=74925&r=fixed Fixed in release: https://bugs.php.net/fix.php?id=74925&r=alreadyfixed Need backtrace: https://bugs.php.net/fix.php?id=74925&r=needtrace Need Reproduce Script: https://bugs.php.net/fix.php?id=74925&r=needscript Try newer version: https://bugs.php.net/fix.php?id=74925&r=oldversion Not developer issue: https://bugs.php.net/fix.php?id=74925&r=support Expected behavior: https://bugs.php.net/fix.php?id=74925&r=notwrong Not enough info: https://bugs.php.net/fix.php?id=74925&r=notenoughinfo Submitted twice: https://bugs.php.net/fix.php?id=74925&r=submittedtwice register_globals: https://bugs.php.net/fix.php?id=74925&r=globals PHP 4 support discontinued: https://bugs.php.net/fix.php?id=74925&r=php4 Daylight Savings: https://bugs.php.net/fix.php?id=74925&r=dst IIS Stability: https://bugs.php.net/fix.php?id=74925&r=isapi Install GNU Sed: https://bugs.php.net/fix.php?id=74925&r=gnused Floating point limitations: https://bugs.php.net/fix.php?id=74925&r=float No Zend Extensions: https://bugs.php.net/fix.php?id=74925&r=nozend MySQL Configuration Error: https://bugs.php.net/fix.php?id=74925&r=mysqlcfg