Comments by amirea - CodeProject

amirea 1-Mar-21 8:56am View

Thank you for sticking around and helping me! It turned out that my code was valid but it took me 1.5 days to figure out that the errors are a bug of the IDE's. After building with the errors still there, the errors were gone.
It didn't occur to me but I found this:

https://stackoverflow.com/questions/3015624/how-to-declare-type-conversion-in-header-file-and-implement-in-cpp-file

and please see the op comment saying it worked with clean project:

https://stackoverflow.com/questions/3015624/how-to-declare-type-conversion-in-header-file-and-implement-in-cpp-file#comment3082516_3015624

and I admit I had my reserves, I tried clean -- didn't work, then built and that solved it. Still, that's a shame... What would happen if the project would need 5 minutes of build time? Imagine building at every error :)

Back to your code: it is clearer than what I wrote and I'll go with that. Thanks again.

amirea 26-Feb-21 3:54am View

Thanks. There's a problem though, all information and examples on custom conversion function I found on Google, including that at the link you provided don't involve namespaces. And they don't present it split into header and implementation files.
_This_ apparently makes the difference in my case.

amirea 25-Feb-21 13:53pm View

I know the types, I chose to use integer instead of floating point for precision and consistency reasons. And thank you for pointing that out, there's never too much or too obvious information.

amirea 25-Feb-21 13:49pm View

Thank you for taking a look at the code. I don't want to just get things done. I want to learn the proper way to do it. Learn once, use it forever :)

amirea 25-Feb-21 13:45pm View

I must got them confused. I thought they were the same thing.

amirea 25-Feb-21 11:42am View

I am sorry, as I was saying -- I'm just starting with interop and I probably didn't properly articulate my question.
It was recently that I found out:
1. Primary types are not copied but directly accessed (shared) between runtimes.
2. Arrays are shared as well.
3. structs are passed by value but one can avoid this by passing as <code>ref and pointers.
4. classes are copied. But one can avoid this by manually pinning through custom marshaling the type.
5. In all automatic cases (non-custom marshaling) P/Invoke internally takes care of pinning as appropriate from case to case.
6. IntPtr is automatically translated back and forth to void*.

amirea 23-Feb-21 8:29am View

Thanks for the comment. I'm not using CLI. just C#/.NET and C++. Also I think I'm missing something on the utility of memory pinning.
My impression is that pinning is necessary in order to refer to the very same variable instance from both runtimes and work with it directly. And that without pinning, a variable would be marshaled (copied or "translated").
Is my knowledge correct? I could be wrong in 2 ways:
1. Maybe you can directly reference an unpinned memory and view it as the variable.
2. Either pinned or not, variable would be marshaled and there wouldn't be any direct interaction with the variable but only through "mediation".

amirea 15-Feb-21 12:03pm View

Thank you for the insight! I won't be updating all of those very often, just some of them at a given moment.
"each communication is real workload which costs performance"
I'll send all of them in a single call, in an array from C++ to C#.
"Any typed pointer has the advantage of helping you debug - with the cost of some performance"
In this particular case I prefer performance over the debugging options.

There are so many options apparent to me -- somebody that knows next to nothing about the matter but I'm sure there are really just a couple of valid solutions, out of which there's one that fits the bill.

Ideally pinning the object in memory isn't needed (?) and I may get away with ref in C# and & or void* on C++ side.

Comments by amirea (Top 8 by date)