Bug 32022 - Decimal precision of SecondsSinceReferenceDate truncated
Summary: Decimal precision of SecondsSinceReferenceDate truncated
Alias: None
Product: iOS
Classification: Xamarin
Component: Xamarin.iOS.dll ()
Version: master
Hardware: PC Mac OS
: Normal normal
Target Milestone: 15.6
Assignee: Sebastien Pouliot
Depends on:
Reported: 2015-07-16 08:36 UTC by Rolf Bjarne Kvinge [MSFT]
Modified: 2017-10-24 15:02 UTC (History)
3 users (show)

Is this bug a regression?: No
Last known good build:

Workbook showing difference in time subtraction precision (1.21 KB, text/plain)
2017-07-24 20:00 UTC, Larry O'Brien

Notice (2018-05-24): bugzilla.xamarin.com is now in read-only mode.

Please join us on Visual Studio Developer Community and in the Xamarin and Mono organizations on GitHub to continue tracking issues. Bugzilla will remain available for reference in read-only mode. We will continue to work on open Bugzilla bugs, copy them to the new locations as needed for follow-up, and add the new items under Related Links.

Our sincere thanks to everyone who has contributed on this bug tracker over the years. Thanks also for your understanding as we make these adjustments and improvements for the future.

Please create a new report on Developer Community or GitHub with your current version information, steps to reproduce, and relevant error messages or log files if you are hitting an issue that looks similar to this resolved bug and you do not yet see a matching new report.

Related Links:

Comment 1 Larry O'Brien 2017-07-24 20:00:11 UTC
Created attachment 23762 [details]
Workbook showing difference in time subtraction precision

Attached is a workbook that illustrates different precisions for `SecondsSinceReferenceDate - SecondsSinceReferenceDate` vs `(DateTime - DateTime).TotalSeconds` 

It actually seems to me that it's `TotalSeconds` that's truncating, but one way or the other, you would expect the result to be the same, but they are not.
Comment 2 Larry O'Brien 2017-07-24 20:01:18 UTC
Switching status to "Confirmed" since I can recreate discrepancy between the two precisions.
Comment 3 Larry O'Brien 2017-07-24 20:12:57 UTC
I'm not sure if this is the same bug, but:

    var a = NSDate.Now
    a.SecondsSinceReferenceDate - ((NSDate) (DateTime) a).SecondsSinceReferenceDate

Comment 4 Sebastien Pouliot 2017-10-24 01:19:02 UTC
PR https://github.com/xamarin/xamarin-macios/pull/2916
Comment 5 Sebastien Pouliot 2017-10-24 15:02:01 UTC
PR merged in master https://github.com/xamarin/xamarin-macios/commit/523e95182e9abb3b8ba77215dbe0105555c04e14

Includes unit test