在平常的开发工作中，单例是我们经常使用的模式，经常我们需要写无数个单例类，现在提供一种单例模板：

#pragma once// common include#include 
    
     #include 
     
      #include 
      
       	// windows include	#if defined _WIN32#else// linux include#include 
       
        #endif	template 
        
          class Singleton{protected:	static T* singleton_;public:	Singleton(void)	{		assert(!singleton_);#if defined(_MSC_VER) && _MSC_VER < 1200	 		int offset = (int)(T*)1 - (int)(Singleton 
         
          *)(T*)1; singleton_ = (T*)((int)this + offset);#else singleton_ = static_cast< T* >(this);#endif } ~Singleton(void){ assert(singleton_); singleton_ = 0; } static T& getSingleton(void) { assert(singleton_); return (*singleton_); } static T* getSingletonPtr(void){ return singleton_; }};#define _SINGLETON_INIT( TYPE ) \template <> TYPE * Singleton< TYPE >::singleton_ = 0; \
         
        
       
      
     
    

template<> A* Singleton<A>::singleton_ = 0;

_SINGLETON_INIT(A)