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To: "'Patrick Schaaf'" <php@bof.de>, internals@lists.php.net, "Frank Liepert"
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Cc: "'Derick Rethans'" <derick@php.net>, "'Martin Jansen'"
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Date: Mon, 04 Feb 2013 12:32:42 +0100
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Subject: Re: AW: [PHP-DEV] FILTER_VALIDATE_INT and +0/-0
From: glopes@nebm.ist.utl.pt ("Gustavo Lopes")

On Mon, 04 Feb 2013 12:14:50 +0100, Frank Liepert <Frank.Liepert@gmx.de>=
  =

wrote:

> The change to FILTER_VALIDATE_INT seems to be inconsistent.
>
> First of all, take the following bug  =

> (https://bugs.php.net/bug.php?id=3D54096) where it says "PHP defines -=
0 as  =

> an int.". Where does PHP define it? The documentation says: "An intege=
r  =

> is a number of the set =E2=84=A4 =3D {..., -2, -1, 0, 1, 2, ...}."
>
> Secondly, try the following code: var_dump(round(-0.1));
> What is the result? Surprise: float(-0)
> And it is not a bug (https://bugs.php.net/bug.php?id=3D42477)
>
> To sum it up:
> - FILTER_VALIDATE_INT should never treat "+0" or "-0" as valid integer=
s.
> - Instead, var_dump needs to be corrected.
> - It could be even gone further in adding support for signed zero  =

> arithmetic (see IEEE754).
>

You're confusing things. Floats are irrelevant to this discussion. It's =
 =

clear -0. (float) does exist and has a well defined meaning. The situati=
on  =

is manifestly different for integers because there are no separate  =

positive and negative 0 integers in most likely all the architectures PH=
P  =

runs on.

So the question is only whether "+0" or "-0" (or "+0", etc.) should be  =

accepted as integers by FILTER_VALIDATE_INT. I think they should, becaus=
e  =

we also accept non-canonical inputs such as "+5", i.e., we always accept=
 a  =

sign. It's true that 0 is neither positive or negative, but I don't thin=
k  =

"accepts a leading sign, except if it's 0" is a good option. It's an  =

unnecessary special case.

Finally, please don't top post. See  =

http://lxr.php.net/xref/PHP_TRUNK/README.MAILINGLIST_RULES#67

-- =

Gustavo Lopes