ASPN ActiveState Programmer Network
ActiveState
/ Home / Perl / PHP / Python / Tcl / XSLT /
/ Safari / My ASPN /
Cookbooks | Documentation | Mailing Lists | Modules | News Feeds | Products | User Groups


Recent Messages
List Archives
About the List
List Leaders
Subscription Options

View Subscriptions
Help

View by Topic
ActiveState
.NET Framework
Open Source
Perl
PHP
Python
Tcl
Web Services
XML & XSLT

View by Category
Database
General
SOAP
System Administration
Tools
User Interfaces
Web Programming
XML Programming


MyASPN >> Mail Archive >> php-dev
php-dev
#50080 [Opn->Bgs]: 1 bit short of an 8 byte integer
by jani other posts by this author
Nov 4 2009 2:52PM messages near this date
#50080 [Bgs]: 1 bit short of an 8 byte integer | #50080 [Com]: 1 bit short of an 8 byte integer
ID:               50080
 Updated by:       jani@[...].net
 Reported By:      aidevelopment at gmail dot com
-Status:           Open
+Status:           Bogus
 Bug Type:         Variables related
 Operating System: Linux 2.6.15-26-server
 PHP Version:      5.2.11
 New Comment:

No.


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

[2009-11-04 17:59:05] aidevelopment at gmail dot com

I understand what you are saying. However, the handling is very
difficult to understand. As you can see, adding 1 simply has no effect
past positive 0
(1000000000000000000000000000000000000000000000000000000000000000). I
have not been able to determine yet exactly what happens when you
explicitly assign a variable to a value "too large".

Is there no way to have PHP utilize 64 bit values (uint64)?

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

[2009-11-04 17:17:58] sjoerd@[...].net

In a 64 bit integer, 1 bit indicates the sign and 63 bits are left for
the number. Thus the range is from -2^63 to 2^63, giving 2^64 numbers.

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

[2009-11-04 16:14:21] aidevelopment at gmail dot com

Description:
------------
Despite having PHP_INT_MAX set to 8 bytes, It is impossible to have an
int greater than
1000000000000000000000000000000000000000000000000000000000000000.
8 Byte, or 64 bit maximum should be
1111111111111111111111111111111111111111111111111111111111111111.

In my included example, it is clear that when attempting to increase
the value above(by adding 1), simply nothing happens.

Attempting to assign a variable to a number greater than the above
number produces unpredictable results.


Reproduce code:
---------------
<?php
echo "Int Size = ".PHP_INT_SIZE." bytes.<br> ";
$status = 0x7FFFFFFFFFFFFFFF;
for($i=0;$i<=4;$i++)
{
        printf ("status = '%b'<br> ", $status);
        $status++;
}
?> 


Expected result:
----------------
Int Size = 8 bytes.
status =
'111111111111111111111111111111111111111111111111111111111111111'
status =
'1000000000000000000000000000000000000000000000000000000000000000'
status =
'1000000000000000000000000000000000000000000000000000000000000001'
status =
'1000000000000000000000000000000000000000000000000000000000000010'
status =
'1000000000000000000000000000000000000000000000000000000000000011'

Actual result:
--------------
Int Size = 8 bytes.
status =
'111111111111111111111111111111111111111111111111111111111111111'
status =
'1000000000000000000000000000000000000000000000000000000000000000'
status =
'1000000000000000000000000000000000000000000000000000000000000000'
status =
'1000000000000000000000000000000000000000000000000000000000000000'
status =
'1000000000000000000000000000000000000000000000000000000000000000'


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


-- 
Edit this bug report at http://bugs.php.net/?id=50080&edit=1
Thread:
Aidevelopment At Gmail Dot Com
Aidevelopment At Gmail Dot Com
jani
Aidevelopment At Gmail Dot Com
sjoerd

Privacy Policy | Email Opt-out | Feedback | Syndication
© ActiveState Software Inc. All rights reserved