Question

If you have this generic function:

template<class type, class ret, class atype1, class atype2, class atype3>
ret call3(type *pClass, ret(type::* funcptr)(atype1, atype2, atype3), atype1 arg, atype2 arg2, atype3 arg3)
{
    //do some stuff here
    return (pClass->*funcptr)(arg, arg2, arg3);
}

and you do this:

class MyClass
{
  public: 
    void test(int, int, int){};
    void test(int, int){};
    void test(int, int, const char *){};  //comment this line, and it works fine.
};

...

    MyClass *a = new MyClass();
    call3(a, &MyClass::test, 1, 2, 3);

g++ will say:

no matching function for call to `call3(MyClass*&, <unknown type>, int, int, int)'

Is there any way to fix this?
(My code is probably very bad also since I’m not very good at C++.)

Answer 1

You can explicitly specify which template to use.

call3<MyClass, void, int, int, int>( a, &MyClass::test, 1, 2, 3 );

If you rearange the order of your template parameters, you can get the MyClass and void deduced from the argument, so the call when needing an overload will look like this:

call3<int,int,int>( a, &MyClass::test, 1, 2, 3 )

Note that when you dont actually need the explicit overload resolution it can still be

call3( a, &MyClass::otherfunction, 1,2,3 );