Bug #74355 [Opn]: DateInterval::format() with "%F" sometimes shows incorrect value by 1us
| From: | heiglandreas@php.net | Date: | Fri, 21 Apr 2017 11:59:27 +0000 |
| Subject: | Bug #74355 [Opn]: DateInterval::format() with "%F" sometimes shows incorrect value by 1us | ||
| References: | 1 | Groups: | php.bugs |
| Request: | Send a blank email to php-bugs+get-208700@lists.php.net to get a copy of this message | ||
Edit report at https://bugs.php.net/bug.php?id=74355&edit=1
ID: 74355
Updated by: heiglandreas@php.net
Reported by: for-bugs at hnw dot jp
Summary: DateInterval::format() with "%F" sometimes shows
incorrect value by 1us
Status: Open
Type: Bug
Package: Date/time related
Operating System: Any
PHP Version: 7.1.3
Block user comment: N
Private report: N
New Comment:
The floating-point inaccuracy you are describing is far below the millisecond-range. The
fraction-issue you are pointing out here relates to a mismatch of 299 meters when you're
calculating distances based on the speed of lightâ¦
In GPS a timing-error of 0.0001 second results in a 0.8m offset, so for the timing error we're
talking about here we have an offset of 8mm
Is this really relevant?
I'd rather say we document that it might be possible that the last digit of the fraction might
be off by one.
Previous Comments:
------------------------------------------------------------------------
[2017-04-01 06:31:52] for-bugs at hnw dot jp
Another example:
<?php
$dt1=new DateTime("2000-01-01 00:00:00");
$dt2=new DateTime("2006-01-02 03:04:05.000251");
$interval = $dt1->diff($dt2);
var_dump($interval->format("%R%Y-%M-%D %H:%I:%S.%F"));
/* Output: string(25) "+06-00-01 03:04:05.000250" */
------------------------------------------------------------------------
[2017-04-01 01:35:04] for-bugs at hnw dot jp
Description:
------------
From PHP 7.1.0, DateInterval::format() supports "%F" parameter which shows fraction of
DateInterval. However, sometimes "%F" prints incorrect value because of floating point
inaccuracy.
Test script:
---------------
<?php
$dt1=new DateTime("2000-01-01 00:00:00");
$dt2=new DateTime("2006-01-02 03:04:05.524287");
$interval = $dt1->diff($dt2);
var_dump($interval->format("%R%Y-%M-%D %H:%I:%S.%F"));
Expected result:
----------------
string(25) "+06-00-01 03:04:05.524287"
Actual result:
--------------
string(25) "+06-00-01 03:04:05.524286"
------------------------------------------------------------------------
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Edit this bug report at https://bugs.php.net/bug.php?id=74355&edit=1