> Aren't the macros expanded by the preprocessor, and end up as a specific piece of code under a function name in a library? Sure, but you don't know the name

> Aren't the macros expanded by the preprocessor, and end up as a specific piece of code under a function name in a library? Sure, but you don't know the name of that function so you can't write the FFI declaration for it. You could reverse engineer it, but this would be platform and compiler specific, so non-portable and unstable.