Question

I stumbled on the same problem of nested templates described here.

The following code :

# include <cstdlib>  // for std::size_t

template<std::size_t N>
class Outer
{
public :
  template<typename T>
  class Inner
  {
      public :
        inline Inner<T> & operator ++ (void) ;
        inline Inner<T>   operator ++ (int) ;
  } ;
} ;

template<std::size_t N>
template<typename T>
inline typename Outer<N>::template Inner<T> & Outer<N>::Inner<T>::operator ++ (void)
{   //                    ^^^^^^^^ Point Of Interest : MSVC is the only one who complains
    // preincrement
}

template<std::size_t N>
template<typename T>
inline typename Outer<N>::template Inner<T>   Outer<N>::Inner<T>::operator ++ (int)
{   //                    ^^^^^^^^ Point Of Interest
    // postincrement
}

只要返回型号有<代码>template的关键词,与MinGW 4.5(即gcc)一起汇编罚款,但MSVC2010对申报/定义不匹配提出抱怨:

error C2244:  Outer::Inner::operator ++  : unable to match function definition to an existing declaration
1>  definition
1>     Outer::Inner &Outer::Inner::operator ++(void) 
1>  existing declarations
1>     Outer::Inner Outer::Inner::operator ++(int) 
1>     Outer::Inner &Outer::Inner::operator ++(void)  <- This is what it wants !

在删除<代码>template关键词时,MSVC汇编了罚款,而gcc成为愤怒:

error: non-template  Inner  used as template
note: use  Outer::template Inner  to indicate that it is a template

加入,MSVC似乎有过错。因此,我的问题是:

How to adapt the above code in order to compile with both MSVC and GCC ? I really want to avoid this awful preprocessor hack :
```
# ifdef MSVC
# define nested_template 
# else
# define nested_template template
# endif
```

然后,使用<条码>,在MSVC, 即<条码>。

If impossible, how to refactor/redesign the code to avoid the nested templates case ?

Answer 1

实际上,定义是在你们需要加固模板的许多地方交叉汇编者支持的途径。 Boo!

另一种选择是,在额外负责人中保存所有你的封顶模板,并在特别志愿人员委员会和海合会有不同的途径。

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