Edit report at http://bugs.php.net/bug.php?id=54842&edit=1
ID: 54842 Updated by: ras...@php.net Reported by: php at maisqi dot com Summary: ceil yields a negative zero -Status: Open +Status: Bogus Type: Bug Package: *Math Functions Operating System: Windows XP32 PHP Version: 5.3.6 Block user comment: N Private report: N New Comment: This is not a bug. All floating point operations is done using IEEE-754 and both positive and negative 0 exists. You can read more about it here. http://en.wikipedia.org/wiki/Signed_zero You can add 0 to your result to make it never show -0 if you like. eg. 0+ceil(...) Previous Comments: ------------------------------------------------------------------------ [2011-05-18 17:24:03] php at maisqi dot com Description: ------------ When doing some math with dates and "ceiling" the result, I got a negative zero! I don't understand how that can be, so I presume it's an error. Test script: --------------- <?php $dt = mktime (0, 0, 0, 5, 18, 2011); $base = mktime (16, 16, 0, 5, 18, 2011); echo 'dt: ', date ('Y-m-d', $dt), '<br />'; echo 'base: ', date ('Y-m-d', $base), '<br />'; echo '<br />'; echo 'dt - base: <strong>', ceil (($dt - $base) / 86400), '</strong>'; ?> <br /><br /> It outputs "-0" on PHP 5.3.6, under Windows XP 32 bits Expected result: ---------------- The bolded text should be "0" (zero) Actual result: -------------- The bolded text is "-0" (negative zero) ------------------------------------------------------------------------ -- Edit this bug report at http://bugs.php.net/bug.php?id=54842&edit=1
