#49418 [Opn->Bgs]: The greatest bug in the history of PHP
ID: 49418
Updated by: colder@php.net
Reported By: ilies dot radu at gmail dot com
-Status: Open
+Status: Bogus
Bug Type: Variables related
Operating System: MacOSX, NetBSD, Linux
PHP Version: 5.2.10
New Comment:
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://docs.sun.com/source/806-3568/ncg_goldberg.html
Thank you for your interest in PHP.
Previous Comments:
------------------------------------------------------------------------
[2009-08-30 17:29:54] ilies dot radu at gmail dot com
Description:
------------
---- Example #1 / FAIL (This should NOT FAIL, but it does) !!!!!!!!!!!
$a=1.3333;
$b=1.6666;
$c=2.9999;
$d=($a+$b);
if($d != $c) {
echo 'php have a serious bug ...';
} else {
echo 'OK ...';
} //end if else
// notice that currently I use number_format($d, 4, '.', '') to fix
this, but is abnormal !
----
---- Example #2 / OK
$a=4.3333;
$b=4.6666;
$c=8.9999;
$d=($a+$b);
if($d != $c) {
echo 'php have a serious bug ...';
} else {
echo 'OK ...';
} //end if
// this seems that not raise that bug, ... hmmm ... very strange
----
I tested it on:
PHP 4.4.9
PHP 5.2.9
PHP 5.2.10
PHP 4.4.4 (bundled with Zend Studio)
It appears that all fail at Example #1 and should not ... !!!
If you release a patch, please also patch the 4.4.9 version.
Reproduce code:
---------------
$a=1.3333;
$b=1.6666;
$c=2.9999;
$d=($a+$b);
if($d != $c) {
echo 'php have a serious bug ...';
} else {
echo 'OK ...';
} //end if else
Expected result:
----------------
the output should be 'OK ...'
but is not !
Actual result:
--------------
'php have a serious bug ...'
------------------------------------------------------------------------
--
Edit this bug report at http://bugs.php.net/?id=49418&edit=1
Thread (2 messages)