I've been working on a diary program (ChronoLog). but lately my date and time variable keeps resetting. I've spent hours trying to fix it. I'm wondering if there's a known issue.

On Tuesday, 11 October 2022 at 22:09:34 UTC, Joel wrote:

An ordinary DateTime variable? Those are pretty simple and won't reset unless something else is wrong around it.

Do you have the code online? Or can at least show some of the context around its use?

On Tuesday, 11 October 2022 at 22:21:35 UTC, Adam D Ruppe wrote:

I programmed the date and time stuff past midnight, then I think I had trouble onwards.

Here's code, I've included other code (maybe it can be compiled and run):
https://www.icloud.com/iclouddrive/08fL87THzs2BrI7-lEwXFF0Mw#ChronoLog_etc

I'm just eyeballing the code, is it the g_dateTimeCursor you're concerned about? That's the only one I really see there.

A few things that might explain it:

1. as a global variable, it is thread local. I don't see any use of threads in here, but if you do, each one has a separate copy and other threads won't see the same value. I do see a new Task in places though so maybe it is this... I don't know where that's coming from or what it actually does but possible the different tasks are running in different threads, and thus seeing a different variable. If it is this, you can make the variable shared (then handle the cross thread safety so they don't overwrite each other) and maybe fix it.

2. there's a bunch of places it might be modified from so possible you just overwrite it somewhere....

I also see a _dateTime in there. This is a member of the Control struct.... and since it is a struct, remember it is an independent value whenever you use it, just like an int.

int a = 5;
int getA() { return a; }

int b = getA();
b += 5;

// but a is still 5 here! Because ints are values, when it is returned by the function, it gets an independent copy.

Structs work the same way. So that getControl in base.d returns an independent copy of the control, and this has an independent copy of the _dateTime variable too. Changes to one will not affect the original.

So this might cause your problem too, with the info being lost. It is possible that changing getControl to return ref will help here, but hard to be sure when just eyeballing the code like I am.

Let me know if this helps.

On Tuesday, 11 October 2022 at 23:28:50 UTC, Adam D Ruppe wrote:

Yes! :-D getControl was the issue, I've used ref on its return value now. Thanks so much for your help! :-)