C++ typedef member function signature syntax

Question

I want to declare type definition for a member function signature. Global function typedefs look like this:

typedef int (function_signature)(int, int);
typed         


        

Answer 1

Well basically it can't work (at least I know no way using g++); Using borland c++ compiler there would be the __closure keyword.

The reason why it does not compile is, that sizeof the functionpointer (on a x86 machine) occupies always <<32bits>>; but if you want to point to a class (interface) signature, the sizeof has to be 64bit: 32 bit for the this pointer (as the class interface is in the memory only once) and 32 bit for the actual function

But the __closure keyword is a bcb language 'hack' not standardized...