php.net |  support |  documentation |  report a bug |  advanced search |  search howto |  statistics |  random bug |  login

go to bug id or search bugs for

Bug #39680 Type Casting from float into int
Submitted: 2006-11-29 10:19 UTC Modified: 2006-11-29 13:40 UTC
From: diefans at googlemail dot com Assigned:
Status: Not a bug Package: *Math Functions
PHP Version: 5.2.0 OS: Linux
Private report: No CVE-ID: None
View Developer Edit
Anyone can comment on a bug. Have a simpler test case? Does it work for you on a different platform? Let us know!
Just going to say 'Me too!'? Don't clutter the database with that please !
Your email address:
MUST BE VALID
Solve the problem:
49 + 24 = ?
Subscribe to this entry?

 
 [2006-11-29 10:19 UTC] diefans at googlemail dot com 
Description:
------------
since version 5.2.0 when I cast a negative float smaller than -2147483648 into an int all bits are lost and the minimum Integer value is returned. For positive floats larger than the max integer value all is fine.
It is not possible to perform bitwise calculations with negative overflowing values since all usable information is lost.

Reproduce code:
---------------
echo (int) -40000000000;
echo (int) 40000000000;


Expected result:
----------------
-1345294336
1345294336

Actual result:
--------------
-2147483648
1345294336

Patches

Pull Requests

History

AllCommentsChangesGit/SVN commitsRelated reports
 [2006-11-29 11:30 UTC] tony2001@php.net 
The logic behind this conversion is quite plain:
if (double > LONG_MAX) {
  long = (unsigned long) double;
} else {
  long = (long) double;
}

You can try to compile a simple program in C and see that the result is the same.
 [2006-11-29 12:21 UTC] diefans at googlemail dot com 
So all versions prior 5.2.0 are buggy - right?
 [2006-11-29 13:29 UTC] diefans at googlemail dot com 
I tested (compiled PHP 5.2.0) the DVAL_TO_LVAL macro (in Zend/zend_operators.c) from version 5.1.4
 and could reproduce expected values. 
So the DVAL_TO_LVAL macro from version 5.2.0 performs not equal as in 5.1.4

#define DVAL_TO_LVAL(d, l) (l) = (d) > LONG_MAX ? (unsigned long) (d) : (long) (d)

please check this issue, if it is intended to be there -
 [2006-11-29 13:40 UTC] tony2001@php.net 
>So all versions prior 5.2.0 are buggy - right?
That's right.
 
PHP Copyright © 2001-2025 The PHP Group
All rights reserved. 		Last updated: Sun Oct 26 11:00:02 2025 UTC