note: declarations in dependent base ‘std::basic_ios<char>’ are not found by unqualified lookup

错误信息如题所示。

修改前：

  template<
     typename _CharT,
     typename _Traits = std::char_traits<_CharT>
   >
     class BasicStkIos
     : virtual public std::basic_ios<_CharT, _Traits>
     {
     public:
       typedef basic_stkbuf <_CharT,_Traits>        StkBufType;

       BasicStkIos()
       : mBuf()
       {init(&mBuf) ;};

       BasicStkIos(const char* fName, std::ios::openmode m, const char* pFilter)
       : mBuf(fName, m, pFilter)
       { init(&mBuf) ; }

       StkBufType*
       rdbuf()
       { return &mBuf; }

     protected:
       StkBufType  mBuf;
     };

修改后：

  template<
     typename _CharT,
     typename _Traits = std::char_traits<_CharT>
   >
     class BasicStkIos
     : virtual public std::basic_ios<_CharT, _Traits>
     {
     public:
       typedef basic_stkbuf <_CharT,_Traits>        StkBufType;

       BasicStkIos()
       : mBuf()
       {this->init(&mBuf) ;};

       BasicStkIos(const char* fName, std::ios::openmode m, const char* pFilter)
       : mBuf(fName, m, pFilter)
       { init(&mBuf) ; }

       StkBufType*
       rdbuf()
       { return &mBuf; }

     protected:
       StkBufType  mBuf;
     };