Code Quality: Switch Storage Provider Status UI APIs to use MemberFunction

[dongle-the-gadget]

Resolved / Related Issues

Switch the Storage Provider Status UI APIs from the Stdcall calling convention to MemberFunction, for correctness.

Steps used to test these changes

Tested the Properties window of OneDrive, works as expected.

[0x5bfa]

Since CsWin32 uses StdCall for COM functions, I thought okay with this convention. It uses a wrong conversion?

[dongle-the-gadget]

MemberFunction is more strict, and for our purposes here it differentiates between C# int and C++ HRESULT (which is actually a type alias for int) versus CsWin32 HRESULT type, which is a wrapper around int.
The fact that Stdcall lets us use CsWin32 HRESULT instead of int is kind of by accident, and MemberFunction disallows that.

[0x5bfa]

Is that because the layout the HRESULT from CsWin32 matches the one of int (2 bytes)?

[dongle-the-gadget]

Quote from Jeremy (.NET):

MemberFunction “doesn’t work” with an HResult struct as that’s technically wrong. That’s the whole reason we needed to add it (as an HResult struct works with Stdcall)

As for why it worked, it has to do with registers (that I’m not qualified to talk about)

[0x5bfa]

Thanks.