Pointer to function returning function pointer

Question

I would like to declare a variable of type pointer to function returning pointer to function. Essentially what the following does, but without any typedefs

Answer 1

You can have a look at the declaration of signal() which is a function taking a void(*)() and returning one of those. The variable ptr can be declared like this:

void (*(*ptr)())()

The notation is a bit awkward and clearly inside out. It may be easier to use trailing return types:

auto (*ptr)() -> void (*)()

... or, of course, use trailing return types all the way through:

auto (*ptr)() -> auto (*)() -> void