#45712 [Asn->Csd]: $something == NaN returns true with 5.3, false with 5.2.*

 ID:               45712
 Updated by:       [email protected]
 Reported By:      for-bugs at hnw dot jp
-Status:           Assigned
+Status:           Closed
 Bug Type:         Variables related
 Operating System: *
 PHP Version:      5.2CVS, 5.3CVS, 6CVS (2008-08-05)
 Assigned To:      tony2001
 New Comment:

This bug has been fixed in CVS.

Snapshots of the sources are packaged every three hours; this change
will be in the next snapshot. You can grab the snapshot at
http://snaps.php.net/.
 
Thank you for the report, and for helping us make PHP better.




Previous Comments:
------------------------------------------------------------------------

[2008-08-07 07:37:04] [email protected]

I'm testing a patch for it.

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[2008-08-05 12:52:06] for-bugs at hnw dot jp

NaN is not exact number. So, NaN should not equals itself. Additionaly,
NaN == NaN is false in C. You can see behavior of C as follows.

$ cat nan.c
int main() {double d;d=(-1e300*1e300)/(1e300*1e300);if (d==d) return 1;
else return 2;}
$ gcc nan.c; ./a.out; echo $?
2
$

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[2008-08-05 12:33:17] [email protected]

That $nan == $nan should be true. (like it is with 5.3)

------------------------------------------------------------------------

[2008-08-05 02:39:58] for-bugs at hnw dot jp

Description:
------------
There is == operator's problem dealing with NaN(Not a Number) in PHP
5.3.0alpha1. This behavior is different with PHP 5.0.0-5.2.6, so this is
compatibility problem.

Reproduce code:
---------------
<?php

$nan = (-1e300*1e300)/(1e300*1e300); // float(NAN)

var_dump($nan=='');
var_dump($nan==0.5);
var_dump($nan==50);
var_dump($nan=='500');
var_dump($nan=='abc');
var_dump($nan==$nan);

Expected result:
----------------
bool(false)
bool(false)
bool(false)
bool(false)
bool(false)
bool(false)

Actual result:
--------------
bool(true)
bool(true)
bool(true)
bool(true)
bool(true)
bool(true)


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