(draft) Custom function pointer from dll

function_pointer.cpp

#include <iostream>
#include <string>

#include <type_traits>

template<typename TReturn, typename... TArgs>
class _Proc
{
protected:
	typedef TReturn(*ProcType)(TArgs...);

public:
	_Proc(void * dll, ProcType proc)
		: dll_(dll)
		, proc_(proc)
	{}

	TReturn operator() (TArgs... args)
	{
		std::cout << "ARGS!" << std::endl;
		if (proc_)
		{
			return proc_(args...);
		}
		return TReturn();
	}

private:
	ProcType proc_ = nullptr;
	void * dll_;

};

template<typename TReturn, typename... TArgs>
class Proc
{};

template<typename TReturn, typename... TArgs>
class Proc<TReturn(*)(TArgs...)>
	: public _Proc<TReturn, TArgs...>
{
public:
	Proc(void * dll, _Proc<TReturn, TArgs...>::ProcType proc)
		: _Proc(dll, proc)
	{}
};

template<typename TReturn, typename... TArgs>
class Proc<TReturn(TArgs...)>
	: public _Proc< TReturn, TArgs...>
{
public:
	Proc(void * dll, _Proc<TReturn, TArgs...>::ProcType proc)
		: _Proc(dll, proc)
	{}
};


std::string TestFn(const char *str1, const std::string & str2)
{
	std::cout << "TestFn(" << str1 << ", " << str2 << ")" << std::endl;
	return "OK!";
}

int main()
{
	typedef int(*ProcX)(int);

	Proc<ProcX> x(nullptr, nullptr);
	auto r = x(2);


	Proc<decltype(TestFn)> test(nullptr, TestFn);
	auto r2 = test("string #1", "string #2");

	return 0;
}