Bug #66011 [Com]: Wrong serialize of rounded value

Edit report at https://bugs.php.net/bug.php?id=66011&edit=1 ID: 66011 Comment by: mail at johanntanzer dot at Reported by: proh dot alexey at gmail dot com Summary: Wrong serialize of rounded value Status: Feedback Type: Bug Package: *General Issues PHP Version: Irrelevant Block user comment: N Private report: N New Comment: well that was obvious as you are using strval(), if i do $a = round(1 / 3, 2); var_dump($a, serialize($a)); I get double(0.33) string(22) "d:0.33000000000000002;" on PHP 5.4.6-1ubuntu1.1 (cli) The problem is, i guess, that there is no finite number in the base 2 system that is equal to 0.33, and when you serialize that php takes all the available bits to make it as accurate as possible, so it is serializing the approximation of 0.33 in the base 2 system, which is not equal to 0.33. There is nothing php can do about this since this is just how computers work, but if you know this you could just serialize the strval() version. Previous Comments: ------------------------------------------------------------------------ [2013-10-31 16:08:51] nikic@php.net Can't reproduce this either. Don't see how that result could possible happen with the strval() call in there. ------------------------------------------------------------------------ [2013-10-31 15:55:24] mail at johanntanzer dot at Could not reproduce I get string(4) "0.33" string(11) "s:4:"0.33";" as expected ------------------------------------------------------------------------ [2013-10-31 13:19:34] proh dot alexey at gmail dot com Description: ------------ Wrong serialize of rounded value Test script: --------------- $a = strval(round(1 / 3, 2)); var_dump($a, serialize($a)); Expected result: ---------------- float(0.33) string(7) "d:0.33;" Actual result: -------------- float(0.33) string(59) "d:0.330000000000000015543122344752191565930843353271484375;" ------------------------------------------------------------------------ -- Edit this bug report at https://bugs.php.net/bug.php?id=66011&edit=1