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Bug #64390 round() corrupted
Submitted: 2013-03-08 11:45 UTC Modified: 2013-03-08 12:09 UTC
From: bugzilla77 at gmail dot com Assigned:
Status: Not a bug Package: Math related
PHP Version: 5.5.0alpha5 OS: Win 7
Private report: No CVE-ID: None
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 [2013-03-08 11:45 UTC] bugzilla77 at gmail dot com 
Description:
------------
Negative zero in mathematics does not exist.


Test script:
---------------
<?=round(-0.1)?>


Expected result:
----------------
0


Actual result:
--------------
-0

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 [2013-03-08 12:09 UTC] johannes@php.net 
Floating point values have a limited precision. Hence a value might 
not have the same string representation after any processing. That also
includes writing a floating point value in your script and directly 
printing it without any mathematical operations.

If you would like to know more about "floats" and what IEEE
754 is, read this:
http://www.floating-point-gui.de/

Thank you for your interest in PHP.

.
 [2013-03-08 12:09 UTC] johannes@php.net
-Status: Open +Status: Not a bug
 [2013-03-10 13:27 UTC] anon at anon dot anon 
>Negative zero in mathematics does not exist.
Then you should also report this against most programming environments that have ever existed, because negative zero is that common, and is even part of an international standard for floating-point representation.

https://en.wikipedia.org/wiki/Negative_zero
 
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