//######################################################################	// Log	//######################################################################	void Log(const char* pStream, ...)	{#ifdef _DEBUG		va_list VaList;		char szBuffer[1024];		va_start(VaList, pStream);		vsprintf(szBuffer, pStream, VaList);		va_end(VaList);		std::ofstream fout("log.txt", std::ios::app);		fout<		fout.close();#endif	}	//######################################################################	// DllLoader	//######################################################################	class DllLoader	{		HINSTANCE	m_Handle;		std::string	m_FileName;	public:		DllLoader()		{			m_Handle = 0;		}		~DllLoader()		{		}		bool Load(const char* pFileName)		{			// If a DLL was already loaded, we'll unload it for the new DLL			if(m_Handle)				Release();			// If a filename wasn't supplied, we'll return false			if(!pFileName)			{				Log("DllLoader::Load() - No filename was supplied.\n");				return false;			}			// Load the library			m_Handle = LoadLibrary(pFileName);			// If the library wasn't loaded (for some reason) then we return false			if(!m_Handle)			{				Log("DllLoader::Load() - Library could not be loaded.\n");				return false;			}			Log("DllLoader::Load() - %s was loaded into memory.\n", pFileName);			m_FileName = pFileName;			return true;		}		void Release()		{			// If the DLL wasn't loaded, we can't unload it. So, we return			if(!m_Handle)			{				Log("DllLoader::Release() - A DLL was never loaded into memory.\n");				return;			}			// Free the library			FreeLibrary(m_Handle);			Log("DllLoader::Release() - %s was released.\n", m_FileName.c_str());		}		template <typename GF_FUNCTYPE>		bool GetFunction(const char* pFuncName, GF_FUNCTYPE& fpFunc)		{			// If a DLL wasn't loaded then return false			if(!m_Handle)			{				Log("DllLoader::GetFunction() - A DLL was never loaded into memory.\n");				return false;			}			// If a function name wasn't supplied, then return false			if(!pFuncName)			{				Log("DllLoader::GetFunction() - A function name was not supplied.\n");				return false;			}			// Get the proc. address			fpFunc = (GF_FUNCTYPE)GetProcAddress(m_Handle, pFuncName);			// If the function failed to load, return false			if(!fpFunc)			{				Log("DllLoader::GetFunction() - %s failed to load.\n", pFuncName);				return false;			}			Log("DllLoader::GetFunction() - %s was loaded into memory.\n", pFuncName);			return true;		}	};	//######################################################################	// DllInterface	//######################################################################	template <typename INTERFACETYPE>	class DllInterface	{		// Type definitions for each INTERFACETYPE		typedef bool (*CREATEINTERFACE)(INTERFACETYPE* pInterface, void* pData);		typedef void (*DESTROYINTERFACE)(INTERFACETYPE* pInterface);		INTERFACETYPE	m_pInterface;		DllLoader		m_Loader;	public:		DllInterface()		{			m_pInterface = 0;		}		~DllInterface()		{		}		bool Load(const char* pFileName, void* pData)		{			// If we can't load the dll, then return false			if(!m_Loader.Load(pFileName))				return false;			// If we can't load the function, then return false			CREATEINTERFACE CreateInterface = 0;			if(!m_Loader.GetFunction("CreateInterface", CreateInterface))				return false;			// If we fail to create the interface, then return false			if(!CreateInterface(&m_pInterface, pData))				return false;						// The interface was loaded, return true			return true;		}		void Release()		{			// If the interface wasn't loaded, return			if(!m_pInterface)				return;			// If we can't load the DestroyInterface function, then return false			DESTROYINTERFACE DestroyInterface = 0;			if(!m_Loader.GetFunction("DestroyInterface", DestroyInterface))				return;			// Destroy the interface			DestroyInterface(&m_pInterface);			// Release the DLL			m_Loader.Release();		}		INTERFACETYPE GetInterface() const		{			return m_pInterface;		}	};

#include #include "dftCommon.h"#include "ITextOut.h"dftlib::DllInterface g_TextOut;int WINAPI WinMain(HINSTANCE, HINSTANCE, LPSTR, int){	g_TextOut.Load("TextOut.dll", 0);	g_TextOut.GetInterface()->DrawText("Test 123");	g_TextOut.Release();	return 0;}[/soure]ITextOut#ifndef _ITEXTOUT_H_#define _ITEXTOUT_H_class ITextOut{public:	virtual void DrawText(const char* pString)	= 0;};#endif

#ifndef _TEXTOUT_H_#define _TEXTOUT_H_#include #include "ITextOut.h"class CTextOut : public ITextOut{public:	void DrawText(const char* pString);};extern "C" __declspec(dllexport) bool CreateInterface(ITextOut** pTextOut, void* pData);extern "C" __declspec(dllexport) void DestroyInterface(ITextOut** pTextOut);#endif

#include "TextOut.h"void CTextOut::DrawText(const char* pString){	MessageBox(0, pString, "Message", MB_OK);}extern "C" __declspec(dllexport) bool CreateInterface(ITextOut** pTextOut, void* pData){	if(*pTextOut)		return false;	*pTextOut = new CTextOut;	return *pTextOut != 0;}extern "C" __declspec(dllexport) void DestroyInterface(ITextOut** pTextOut){	if(!*pTextOut)		return;	delete *pTextOut;}