Overloading function in C bindings

Help & Support
1

It looks like I cannot overload functions in C bindings:

@[Link(ldflags: "#{__DIR__}/tst.o")]
lib LibTst
  fun func=func_f(a : Float32) : Float32
  fun func=func_d(a : Float64) : Float64
end

Furthermore, compiler silently uses first function without any warning. Am I missing something here? What is a recommendation to avoid a lot of boilerplate code defining overloads?

2

C doesnā€™t have overloads and so the C bindings in Crystal donā€™t have overloads either. When the compiler finds SomeLib.name(...) it just finds the first (only) one with that name and uses it. If you ā€œoverloadā€ it, like you did in the above example, you actually overwrite it.

Youā€™ll have to use func_f and func_d separately.

You could open an issue to try to discuss this, but I donā€™t think it will be changed soon (if at all). Currently the code that checks C function matching is very different compared to regular Crystal code, mainly because for C we autocast some stuff (to_unsafe), C supports untyped splats, etc.

3

Does it makes sense to show a warning/error if same name is used twice? Or it is impossible due to macros?

4

This should either be an error, or it should use the second definition, please open an issue.

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