Re: LONGINT... ? to be or not to be?...
| From: | Sheridan Saint-Michel | Date: | Tue, 28 Aug 2001 19:54:10 +0000 |
| Subject: | Re: LONGINT... ? to be or not to be?... | ||
| References: | 1 | Groups: | php.general |
| Request: | Send a blank email to php-general+get-64872@lists.php.net to get a copy of this message | ||
A couple of points here... First, 0 is obviously wrong for
3221225472 & 1073741824
But I don't know how you got 2147483648 either.
I get 1073741824 as
3221225472 = 11000000000000000000000000000000
1073741824 = 01000000000000000000000000000000
11000000000000000000000000000000 &
01000000000000000000000000000000 =
01000000000000000000000000000000
right?
Anyways, to your question =P
First, if you check here:
http://www.php.net/manual/en/language.types.integer.php
you will see that int's in PHP are always signed and that if
they exceed the max size for an int they are converted to a
float.
Try running this on your server
<?php
$x = 3221225472;
$y = 1073741824;
echo "x = ";
var_dump($x);
echo "<BR>";
echo "y = ";
var_dump($y);
?>
I would be willing to bet that $x is a float and $y is an int, so
the bitwise operator can't compare them. The only
workaround I can offer you is this
<?php
$x = 3221225472;
$y = 1073741824;
$x = decbin($x);
$y = decbin($y);
$bitand = bindec($x & $y);
echo "Bitwise and gives $bitand";
?>
It's a bit kludgy but it forces both $x and $y to be compared
as binary numbers, which is what you want =)
Sheridan Saint-Michel
Website Administrator
FoxJet, an ITW Company
www.foxjet.com
----- Original Message -----
From: "Alexey Prohorenko" <green@usa.dp.ua>
To: <php-general@lists.php.net>
Sent: Tuesday, August 28, 2001 1:47 PM
Subject: [PHP] LONGINT... ? to be or not to be?...
> Hello,
>
> I have one question. How can PHP work with longint (in C we call
> them "unsigned long") variables?
> F.e., I want to do next thing:
>
> 65536 & 4096 = 0 (this is right)
> 65536 & 65536 = 65536 (again, everything is okay)
> 196608 & 65536 = 65536 (perfect, it works great)
>
> but,
>
> 3221225472 & 1073741824 = 0 (this is wrong, right answer isn't 0
> but 2147483648)
>
> So, can anybody help me with this? Any suggestions?
>
> Thanks, anyway. Looking forward your answers.
> Will check my mailbox every 5 minutes. :-)
>
> --
> green
> [http://www.extrasy.net]
> [http://www.unix-how-to.net]
>
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