Passing a template which requires a comma to a single-argument macro

Question

I have some code that essentially condenses down to

#define FOO(a)
FOO(std::map);

But it emits a compile error (too many ac

Answer 1

This should perhaps ideally be a comment, but SO doesn't support code in comments, so, you can do

#include 

or you can define a macro that resolves to comma, or you can use just about any scheme that's specific to some particular use case (e.g., passing template name separately).