Priority when choosing overloaded template functions in C++

Question

I have the following problem:

class Base
{
};

class Derived : public Base
{
};

class Different
{
};

class X
{
public:
  template 
  stat         


        

Answer 1

You must use SFINAE for this. In the following code, the first function can be instantiated if and only if you pass something that can't be (implicitly) converted to Base *. The second function has this reversed.

You might want to read up on enable_if.

#include 
#include 
#include 

class Base {};
class Derived : public Base {};
class Different {};

struct X
{
    template 
    static typename boost::disable_if,
        const char *>::type func(T *data)
    {
        return "Generic";
    }

    template 
    static typename boost::enable_if,
        const char *>::type func(T *data)
    {
        return "Specific";
    }
};

int main()
{
    Derived derived;
    Different different;
    std::cout << "Derived: " << X::func(&derived) << std::endl;
    std::cout << "Different: " << X::func(&different) << std::endl;
}