可以在gcc中模拟nullptr吗？ [英] Can nullptr be emulated in gcc?

问题描述

我看到 nullptr 在Visual Studio 2010中实现。我喜欢这个概念，并希望尽快开始使用它;然而GCC不支持它。我的代码需要在两者上运行（但不必与其他编译器一起编译）。

I saw that nullptr was implemented in Visual Studio 2010. I like the concept and want to start using it as soon as possible; however GCC does not support it yet. My code needs to run on both (but doesn't have to compile with other compilers).

有没有办法模拟它？像：

Is there a way to "emulate" it? Something like:

#define nullptr NULL

（这显然不会很好，只是为了显示我的意思。）

(That obviously wouldn't work well at all, it's just to show what I mean.)

推荐答案

官方提案有一个解决方法 -

The Official proposal has a workaround -

const                        // this is a const object...
class {
public:
  template<class T>          // convertible to any type
    operator T*() const      // of null non-member
    { return 0; }            // pointer...
  template<class C, class T> // or any type of null
    operator T C::*() const  // member pointer...
    { return 0; }
private:
  void operator&() const;    // whose address can't be taken
} nullptr = {};              // and whose name is nullptr

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