Question

So, say I have the following C++ header, testheader.h:

struct mystruct
{
  struct myinnerstruct
  {
        int x;
  } astruct;
};

struct myinnerstruct
{
    int x;
};

和以下C++来源,test.cpp:

#include "testheader.h"
using namespace std;
int main()
{
    return 0;
}

g ++在汇编/链接中没有问题。

现在,如果我有同样的主人,而不是C++来源,则一份C源文件test.c:

#include "testheader.h"
int main()
{
  return 0;
}

我用快乐汇编,我有以下错误:

error: redefinition of struct myinnerstruct

因此,我认为,C版的范围是翻译单位,C++版本的范围是有限的? 谁能证实这种情况,也许会给我一个理由,说明它为何有意义? 我做一些C和C++编码的混合,这给我带来了很大的麻烦。

Any insight is greatly appreciated. Thanks!

Answer 1

在C区,被nes住的建筑实际上并不在其父母的范围之内。然而,在C++中,它们的确是teststruct:innerstruct 是不同的类别,可到innerstruct。这样做是为了改进C++编码的资本。如果没有这一规则,同一名称空间中没有任何两种类型可以界定一个密封的<编码>iterator类别,例如,这种类别将极为坏。

C treats structs in plenty of other very silly ways, so it s no surprise that they did the wrong thing here. However, C does not otherwise allow type scoping and having a sane rule here would have introduced many additional concepts to the language- ultimately, it would have required the introduction of namespaces, which for some reason was never done.

Answer 2

在C,内障的定义超出了外部结构,C++的情况并非如此。

This has been explained in this blog: Incompatibilities Between ISO C and ISO C++ among many other things in C vs. C++ with a reference to C99 and c++98 ISO standards.

Answer 3

There are no scopes in C, so everything is in the "global" namespace (in C++ speak)

Answer 4

在C和C++上工作的更清洁的方法是:

struct myinnerstruct
{
    int x;
};

struct mystruct
{
  struct myinnerstruct astruct;
};

友情链接