彻底崩溃的VS2005 DLL之Singleton模板

2011-12-15 09:16:50 300 阅读 AI 写同款 · GEO 优化AI 选题数据监测一键分发 ›

C++ 知识补充向量（vector）是一个封装了动态大小数组的顺序容器（SequenceContainer）。跟任意其它类型容器一样，它能够存放各种类型的对象。可以简单的认为，向量是一个能够存放任意类型的动态数组。C++中map提供的是一种键值对容器，里面的数据都是成对出现的,如下图：每一对中的第一个值称之为关键字(key)，每个关键字只能在map中出现一次；第二个称之为该关键字的对应值。阅读详情

class Derived:public TSingleton<Derived>{}

继承自TSingleton<>模板,当new出Derived时,TSingleton<Derived>构造函数向静态变量Derived* s_pInstanceSingleton写入this值.调用TSingleton<>::GetpInstance()能够返回以前写入的this值

问题出在Dll上,使用的是MFC扩展Dll,使用Console调用.测试代码写在Dll01中,TSingleton写在Dll00中.两个Dll中分别定义了一个用于测试的Derived类,分别是CTest02和CTest05,代码几乎一模一样.

类似于
class AFX_EXT_CLASS CTest2:public TSingleton<CTest2>
{
public:
CTest2(void);
virtual ~CTest2(void){}

void SayHello(void)
{
std::cout<<"Hello Test2"<<m_strNameBase<<m_nSeq<<std::endl;
}

void SayHelloMsg(){
AfxMessageBox(_T("Hello Test2"));
}
};
CTest2::CTest2(void):TSingleton(this,"CTest2"){}

Dll01的用例"CTest05"没有问题,异地Dll00的用例 "CTest02"写入后调用GetpInstance返回是Null.后来用GetpInstance2返回了非Null值.但是对象被创建了2次.从Console输出可以看到.
更加诡异的是如果将CTest02的构造函数写在.h文件(class结构内)中,则没有问题.而写在.cpp中,即使加了inline也没有用

template的静态指针型变量象蒸发了一样.

翻阅了Addison的C++ Templates: The Complete Guide 好像似乎有个章节是CRTP,不过没有深入展开.
安装的是VS2005sp1英文版,不知道是何原因?

MFC Ext Dll00



//Singleton.h,基础类,检查是否有违规

class AFX_EXT_CLASS CSingleton

{

protected:

	static std::set<std::string> s_setStr;

public:

	CSingleton(const std::string& strName);

	virtual ~CSingleton(void){}

};

//Singleton.cpp,基础类,检查是否有违规

std::set<std::string> CSingleton::s_setStr;



CSingleton::CSingleton(const std::string& strName)

{

	if(s_setStr.find(strName)!=s_setStr.end()){

		std::cout<<"duplicate!"<<std::endl;

	}

	s_setStr.insert(strName);

}



//TSingleton.h,模板类



template<class Tp>

class TSingleton:public CSingleton

{

protected:

	static Tp* s_pInstanceSingleton;

	static std::string s_strSingletonName;

	std::string m_strNameBase;

	static int m_nSeq;

protected:

	TSingleton(Tp* pThis,const std::string& strT);/*:CSingleton(strT);

	{

		s_strSingletonName=strT;

		s_pInstanceSingleton=pThis;

	}*/

	virtual ~TSingleton(void)

	{

		s_pInstanceSingleton=NULL;

		std::cout<<"deleted: "<<s_strSingletonName<<std::endl;

	}

public:

	static Tp* GetpInstance()	//with no auto create

	{

		if(s_pInstanceSingleton){

			std::cout<<"GetpInstance() success: "<<s_strSingletonName<<std::endl;

			return s_pInstanceSingleton;

		}

		std::cout<<"fail to load class's instance: "<<s_strSingletonName<<std::endl;

		return NULL;

	}

	static Tp* GetpInstance2()	//with auto create

	{

		if(s_pInstanceSingleton){

			std::cout<<"GetpInstance2() success: "<<s_strSingletonName<<std::endl;

			return s_pInstanceSingleton;

		}

		s_pInstanceSingleton=new Tp;

		AfxMessageBox(_T("new instance"));

		return s_pInstanceSingleton;

	}

};





template<class Tp> Tp* TSingleton<Tp>::s_pInstanceSingleton;

template<class Tp> std::string TSingleton<Tp>::s_strSingletonName="unknown";

template<class Tp> int TSingleton<Tp>::m_nSeq=0;



template<class Tp>  TSingleton<Tp>::TSingleton(Tp* pThis,const std::string& strT):CSingleton(strT),s_pInstanceSingleton(pThis)

{

	this->s_strSingletonName=strT;

	this->s_pInstanceSingleton=pThis;

	this->m_strNameBase=strT;

	this->m_nSeq++;

	std::cout<<m_strNameBase<<" created: "<<m_nSeq<<std::endl;

	//s_pInstanceSingleton=dynamic_cast<Tp*>(this);

}





//测试体02.h



class AFX_EXT_CLASS CTest2:public TSingleton<CTest2>

{

public:

	CTest2(void);

	virtual ~CTest2(void){}

	

	void SayHello(void)

	{

		std::cout<<"Hello Test2"<<m_strNameBase<<m_nSeq<<std::endl;

	}

	

	void SayHelloMsg(){

		AfxMessageBox(_T("Hello Test2"));

	}

};



//测试体02.cpp



CTest2::CTest2(void):TSingleton(this,"CTest2"){}

MFC EXT DLL01



//测试体05.h

#include "stdafx.h"



class AFX_EXT_CLASS CTest5:public TSingleton<CTest5>

{

public:

	CTest5(void);

	virtual ~CTest5(void);

	void SayHello(void);

	void SayHelloMsg();



};

//测试体05.cpp

CTest5::CTest5(void):

TSingleton(this,"CTest5")

{

}



CTest5::~CTest5(void)

{

}



void CTest5::SayHello(void)

{

	std::cout<<"Hello Test5"<<std::endl;

}



void CTest5::SayHelloMsg()

{

	AfxMessageBox(_T("Hello Test5"));

}



//测试CTest02,CTest05



#include "Test5.h"



class AFX_EXT_CLASS CTestAll

{

public:

	CTestAll(void);

	virtual ~CTestAll(void);

public:

	void TestConsole()

	{

		new CTest2;

		CTest2* pTest2=CTest2::GetpInstance();

		if(pTest2){

			pTest2->SayHello();

		}else{

			std::cout<<"Call Fail 2"<<std::endl;

			pTest2=CTest2::GetpInstance2();

			CTest2::GetpInstance()->SayHello();

		}

		

		new CTest5;

		CTest5* pTest5=CTest5::GetpInstance();

		if(pTest5){

			pTest5->SayHello();

		}else{

			std::cout<<"Call Fail 5"<<std::endl;

			pTest5=CTest5::GetpInstance2();

			CTest5::GetpInstance()->SayHello();

		}

		delete pTest2;

		delete pTest5;

	}

	void TestGui()

	{

		new CTest2;

		CTest2* pTest2=CTest2::GetpInstance();

		if(pTest2){

			pTest2->SayHelloMsg();

		}else{

			AfxMessageBox(_T("Call Fail 2"));

			pTest2=CTest2::GetpInstance2();

			CTest2::GetpInstance()->SayHello();

		}



		new CTest5;

		CTest5* pTest5=CTest5::GetpInstance();

		if(pTest5){

			pTest5->SayHelloMsg();

		}else{

			AfxMessageBox(_T("Call Fail 5"));

			pTest5=CTest5::GetpInstance2();

			CTest5::GetpInstance()->SayHello();

		}

		delete pTest2;

		delete pTest5;

	}

};

MFC console Exe文件,Depends on Dll00,Dll01





int _tmain(int argc, TCHAR* argv[], TCHAR* envp[])

{

	int nRetCode = 0;



	// initialize MFC and print and error on failure

	if (!AfxWinInit(::GetModuleHandle(NULL), NULL, ::GetCommandLine(), 0))

	{

		// TODO: change error code to suit your needs

		_tprintf(_T("Fatal Error: MFC initialization failed\n"));

		nRetCode = 1;

	}

	else

	{

		CTestAll test;

		test.TestConsole();

	}



	return nRetCode;

}