What happens whenever an inline function is registered to AS? I accidentaly did it and it actually worked, but is it safe?

In C++, inline is a hint and largely ignored by modern compilers, which use their own heuristics to decide when to inline functions. Its main purpose is to allow the implementation of small functions in header files without causing linker errors. Taking the address of an inline function will generally cause the compiler to generate a out of line copy in the final executable. I don't know if any compilers are capable of avoiding this, even in simple cases where the function pointer is pointing at a fixed address, but they are allowed to.

It is safe.