Unordered map: issue using class member function pointer

Question

I have the following problem: I am writing a simple chip8 emulator, and have a massive class of interpreter functions that I would like to access via opcodes as keys, such a

Answer 1

Use std::invoke from the header functional to execute it (C++17):

test t;
std::invoke(iter->second, t);

After all, you need to invoke it on an object. The method on its own cannot be executed.

If you don't have C++17 (IIRC):

test t;
(t.*(iter->second))();