I don't see any switch to specify the "C version" in the cppwinrt.exe tool !

(my fundamental assumption is cppwinrt.exe tool binds the C 17 syntax to the ABI, I can't figure out how it can bind C 20 or future newer versions syntax )

Similarly, the cswinrt.exe tool from C#/WinRT projection generates .cs files from .winmd files. The same question applies , How does the cswinrt.exe tool know which "C# version" to use to generate the .cs files ?

I don't see any switch to specify the "C# version" in the cswinrt.exe tool either !

end goal : is to understand how "language versions" fit in the WinRT language projections

CodePudding user response：

The cppwinrt.exe tool doesn't allow you to specify a C language standard. It simply defaults to C 17, with the ability to opt-in to newer language features by way of feature test macros.

The result is that the generated header files can be compiled with any C 17 compiler, or a compiler that supports a later language version.

At this time (C /WinRT version 2.0.210806.1) there are only two C 20 features in use:

• C 20 coroutines, guarded by an #ifdef __cpp_lib_coroutine directive (though that is really just deciding on whether to include the coroutine header file from the experimental/ directory or not; coroutines have been supported since VS 2015)
• C 20 modules. This isn't guarded as clients need to explicitly opt-in to using winrt.ixx through an import declaration.

At a fundamental level, C /WinRT is just a C library. As such it can employ any technique that's suitable to providing language-adaptive implementations.

I don't know how C#/WinRT operates internally, nor C# for that matter, so I cannot comment on that.