the identifier __VA_ARGS__ can only appear in the replacement lists of variadic macros

Question

I am attempting to create a macro to perform api calls. My current issue is the passing of parameters for the call. I get the following error message:

#define DO_CALL(api_name)(...) wow64hg::do_call(FNV(#api_name), __VA_ARGS__)

const auto status = DO_CALL(TerminateProcess)(process_handle, 0);

It technically may be possible to fix this by using operator loading, but I am confident there should be a way to keep it simple like this and get it to work.

Nate Eldredge · Answer

Variadic macro syntax doesn't work like that; the ... has to represent additional arguments of the macro.  A macro can't take multiple sets of arguments in separate sets of parentheses like an iterated function call.
I think you have to do the following:
#define DO_CALL(api_name, ...) wow64hg::do_call(FNV(#api_name), __VA_ARGS__)

const auto status = DO_CALL(TerminateProcess, process_handle, 0);

the identifier __VA_ARGS__ can only appear in the replacement lists of variadic macros

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