As far as I’m aware, the only operations that can be done on tokens in the C preprocessor (at least ISO/ANSI standard) is to replace, ‘stringify’ or concatenate them. I’m also unaware of any GCC or MSVC extensions that will let you do what you want.
However, people have been coming up with clever (or oddball) ways to do magical (or horrible) things with macros, so I wouldn’t be surprised if someone surprises me.