Does my code have some problems?

[jonike]

Hi, there.

I'm use your Plugin Framework code to study c++ skill.

Below is my test code: main.cpp

#include <iostream>
#include <string>
#include <map>

class IPrint
{
public:
	virtual ~IPrint(){}

	virtual void print() = 0;
};

template <typename T, typename ...T1>
class TemplateClass:public T
{
public:
	typedef T *(*class_t)(T1...);
	typedef std::map<int, class_t> map_int_t;


	virtual ~TemplateClass(){}

	static int Set(int a, class_t b);

	static T* Get(int a, T1... args);

	static void dump();
private:
	static map_int_t mMapIntContainer;
};

template <typename T, typename ...T1>
typename TemplateClass<T,T1...>::map_int_t TemplateClass<T,T1...>::mMapIntContainer;

template <typename T, typename ...T1>
int TemplateClass<T, T1...>::Set(int a, class_t b)
{
	/*test creation*/
	//T* test = b();
	//delete test;
	std::cout << "create:" << a << std::endl;
	std::cout << "map_size:" << mMapIntContainer.size() << std::endl;
	//mMapIntContainer.insert(std::make_pair(a, b)); // @FixMe: if insert anything will be crashed immediately.
	return 0;
}

template <typename T, typename ... T1>
T* TemplateClass<T, T1...>::Get(int a, T1 ... args)
{
	std::cout << "query:" << a << std::endl;
	std::cout << "map_size:" << mMapIntContainer.size() << std::endl;
	auto it = mMapIntContainer.find(a);
	if(it!=mMapIntContainer.end())
	{
		std::cout << "Find*" << std::endl;
		return (it->second)(args...);
	}
	return nullptr;
}


template <typename T, typename ...T1>
void TemplateClass<T, T1...>::dump()
{
	for(auto s :mMapIntContainer)
	{
		std::cout << s.first << ", " << s.second << std::endl;
	}

}
static int count = 0;
template <typename T, typename T1, typename ...T2>
class StaticReg
{
public:
	static T* factory(T2 ... args)
	{
		std::cout << "sublcass creation" << std::endl;
		return new T1(args...);
	}

	StaticReg(){
		std::cout << "StaticReg::StaticReg" << std::endl;
		std::cout << typeid(T).name() << std::endl;
		TemplateClass<T, T2...>::Set(++count, factory);
		std::cout << "count:" << count << std::endl;
	}
};

template <typename T, typename T1, typename ...T2>
class RealTemplateClass: public TemplateClass<T,T2...>
{
public:
	RealTemplateClass(){}
	static StaticReg<T, T1, T2...> hold_obj;
};

template<typename T, typename T1, typename ...T2>
StaticReg<T, T1, T2...> RealTemplateClass<T, T1, T2...>::hold_obj;

class APrint:public RealTemplateClass<IPrint, APrint>
{
public:
	APrint() { std::cout << "APrint:construct" << std::endl; }
	virtual ~APrint(){}

	void print()
	{
		std::cout << "APrint::print" << std::endl;

	}
};

template class RealTemplateClass<IPrint, APrint>;

class BPrint:public TemplateClass<IPrint, BPrint>
{
public:
	BPrint(){std::cout << "BPrint:construct" << std::endl;}
	virtual ~BPrint(){}
	void print()
	{
		std::cout << "BPrint:print" << std::endl;
	}
};

template class RealTemplateClass<IPrint, BPrint>;

int main()
{
	IPrint* aa_ptr = TemplateClass<IPrint>::Get(1);  // return new APrint();
	if(aa_ptr!=nullptr)
	{
		//APrint* a = dynamic_cast<APrint*>(aa_ptr);
		aa_ptr->print();
		delete aa_ptr;
		aa_ptr = nullptr;
	}
	IPrint* bb_ptr = TemplateClass<IPrint>::Get(2);  // return new BPrint();
	if(bb_ptr!=nullptr)
	{
		//BPrint* b = dynamic_cast<BPrint*>(bb_ptr);
		bb_ptr->print();
		delete bb_ptr;
		bb_ptr = nullptr;
	}
	return 0;
}

When i debug this code in VS 2015 x64.

The debugger tell me :

Line 43:mMapIntContainer.insert(std::make_pair(a, b));

Exception thrown: read access violation.
std::_Tree<std::_Tmap_traits<int,IPrint * __ptr64 (__cdecl*)(void),std::less<int>,std::allocator<std::pair<int const ,IPrint * __ptr64 (__cdecl*)(void)> >,0> >::_Root(...) returned 0x8.

Perhaps it is the std::map container is not initialize?

Can you help me fix this problem? Thanks.