单体模式实现代码

 

刚刚跟朋友讨论单体模式的实现，以下是我为公司写的基类的实现，应该是经过很多项目的考验的，拿出来跟大家探讨下，

 

/**
* @author konyel lin 
* @version 0.1
* @brief Singleton
*/
#include <cassert>
#ifndef EXPORT_H
#define EXPORT_H
#define Export _declspec(dllexport)
#endif
#ifndef _SINGLETON_H__
#define _SINGLETON_H__


template <typename T>  class Singleton
{
    protected:
        static T* ms_Singleton;
    public:
        Singleton( void )
        {
             assert( !ms_Singleton );

//vc编译器
#if defined( _MSC_VER ) && _MSC_VER < 1200     
            int offset = (int)(T*)1 - (int)(Singleton <T>*)(T*)1;
            ms_Singleton = (T*)((int)this + offset);
#else
             ms_Singleton = static_cast<T*>( this );
#endif
        }
        ~Singleton( void )
        { assert( ms_Singleton );  ms_Singleton = 0;  }
        static T& getSingleton( void )
        {    
            assert( ms_Singleton );  
            return ( *ms_Singleton ); 
        }
        static T* getSingletonPtr( void )
        { return ms_Singleton; }
};

#endif