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

go to bug id or search bugs for

Bug #76955 -1*round(0,2) = -0
Submitted: 2018-10-01 07:26 UTC Modified: 2018-10-01 08:06 UTC
From: giolaza at gmail dot com Assigned: cmb (profile)
Status: Not a bug Package: *General Issues
PHP Version: 7.2.10 OS: Windows, Linux
Private report: No CVE-ID: None
View Add Comment Developer Edit
Welcome back! If you're the original bug submitter, here's where you can edit the bug or add additional notes.
If this is not your bug, you can add a comment by following this link.
If this is your bug, but you forgot your password, you can retrieve your password here.
Password:
Status:
Package:
Bug Type:
Summary:
From: giolaza at gmail dot com
New email:
PHP Version: OS:

 

 [2018-10-01 07:26 UTC] giolaza at gmail dot com 
Description:
------------
-1*round(0) = -0

Test script:
---------------
$var= -1*round(0,2);
var_dump($var); //float(-0)
var_dump($var==0); //bool(true)
var_dump($var===0); //bool(false)

$var= -1*round(0);//has same results

Actual result:
--------------
$var= -1*round(0,2);
var_dump($var); //float(-0)
var_dump($var==0); //bool(true)
var_dump($var===0); //bool(false)

Patches

Add a Patch

Pull Requests

Add a Pull Request

History

AllCommentsChangesGit/SVN commitsRelated reports
 [2018-10-01 07:32 UTC] giolaza at gmail dot com 
$var= -1*0;
var_dump($var); //int(0)
var_dump($var==0); //bool(true)
var_dump($var===0); //bool(true)


$var= -1*0.00;
var_dump($var); //float(-0)
var_dump($var==0); //bool(true)
var_dump($var===0); //bool(false)


as we can see we had problem with float type
 [2018-10-01 08:06 UTC] cmb@php.net
-Status: Open +Status: Not a bug -Assigned To: +Assigned To: cmb
 [2018-10-01 08:06 UTC] cmb@php.net 
Floating point values have a limited precision. Hence a value might 
not have the same string representation after any processing. That also
includes writing a floating point value in your script and directly 
printing it without any mathematical operations.

If you would like to know more about "floats" and what IEEE
754 is, read this:
http://www.floating-point-gui.de/

Thank you for your interest in PHP.

A negative zero is to be expected here.
 
PHP Copyright © 2001-2024 The PHP Group
All rights reserved. 		Last updated: Fri Apr 19 08:01:28 2024 UTC