自动foo（...）-> decltype（this）有一些解决方法吗？ [英] auto foo(...) ->decltype(this) Is there some workaround?

问题描述

我有下一个类，并尝试声明成员函数，该函数将返回指向该类型但下一个代码的指针

I have next class and try to declare member function which will return pointer to a that type but next code

template<class Key, int b> class b_plus_tree_inner_node {
  auto split() -> decltype(this) {}
};

给我这样的错误

在顶层无效使用'this'

invalid use of ‘this’ at top level

我可以用另一种方式做到这一点吗，我现在谈到typedef，但使用decltype可能吗？

can i do it in another way, i now about existence of typedef, but may be its possible with decltype?

已编辑：

我想完成此操作：

b_plus_tree_inner_node<Key, b>* split() {...}

推荐答案

如果需要成员函数，请在类中声明它：

If you want a member function declare it inside the class:

template<class Key, int b> class b_plus_tree_inner_node {
   b_plus_tree_inner_node* split(){}
   // also valid:
   //b_plus_tree_inner_node<Key, b>* split(){}
};

如果要使用非成员函数，请将其作为模板：

If you want a non-member function, make it a template:

template<class Key, int b>
b_plus_tree_inner_node<Key, b>* split(){}

该标准确实允许您编写 auto split（）-> decltype（this）{} ，但GCC 4.6尚不支持（GCC 4.7的主干支持）。

The standard does allow you to write auto split() -> decltype(this) {} but GCC 4.6 doesn't support it yet (the trunk of GCC 4.7 does).

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