ID: 42510
User updated by: jr-php2 at quo dot to
Reported By: jr-php2 at quo dot to
-Status: Feedback
+Status: Open
Bug Type: Strings related
Operating System: Linux x86-64
PHP Version: 5.2.4
New Comment:
> Are you actually using PHP 5.2.4?
Yes.
> (the bug you claim to be bogus was fixed already in 5.2.1..
Maybe I wasn't clear: I'm suggesting that the bug report *and* the fix
that went into 5.2.1 are bogus.
Result with PHP 5.2.0 (matches my "expected result"):
unpack = 3368601800
ip2long = 3368601800
Result with PHP 5.2.1-5.2.4:
unpack = -926365496
ip2long = 3368601800
> why didn't you report it earlier?!)
I didn't notice the problem until now.
Previous Comments:
------------------------------------------------------------------------
[2007-09-03 08:14:48] [EMAIL PROTECTED]
Are you actually using PHP 5.2.4? (the bug you claim to be bogus was
fixed already in 5.2.1..why didn't you report it earlier?!)
------------------------------------------------------------------------
[2007-09-02 20:06:52] jr-php2 at quo dot to
Digging deeper, it looks like 'V' and 'N' used to work as documented
until bug #38770 was "fixed in CVS".
Isn't #38770 a bogus report, though? Since 'N' is documented as being
unsigned, isn't the user wrong to expect it to return a negative result?
------------------------------------------------------------------------
[2007-09-01 20:33:57] jr-php2 at quo dot to
Okay, looking at the unpack() code, it appears that:
- 'l' and 'L' are both treated as signed, even though 'l' is documented
as signed and 'L' is documented as unsigned.
- 'N' and 'V' are treated as signed, even though both are documented as
unsigned.
So who's right here, the code or the documentation?
------------------------------------------------------------------------
[2007-09-01 17:26:12] jr-php2 at quo dot to
Sorry, I mixed up the expected and actual results.
It should say:
Expected result:
----------------
unpack = 3368601800
ip2long = 3368601800
Actual result:
--------------
unpack = -926365496
ip2long = 3368601800
------------------------------------------------------------------------
[2007-09-01 17:22:10] jr-php2 at quo dot to
Description:
------------
On x86-64, unpack('V') sign-extends from 32-bit to 64-bit. In other
words, it can return a negative number.
Since 'V' specifies an *unsigned* 32-bit value, this is incorrect; the
upper 32 bits of the 64-bit result should always be zero.
This behavior makes unpack() inconsistent with other functions like
ip2long() and crc32() which never return negative numbers on 64-bit PHP.
Reproduce code:
---------------
$u = unpack('Vresult', chr(200).chr(200).chr(200).chr(200));
echo "unpack = ", $u['result'], "\n";
echo "ip2long = ", ip2long('200.200.200.200'), "\n";
Expected result:
----------------
unpack = -926365496
ip2long = 3368601800
Actual result:
--------------
unpack = 3368601800
ip2long = 3368601800
------------------------------------------------------------------------
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Edit this bug report at http://bugs.php.net/?id=42510&edit=1
