为什么以这种方式声明GUID结构? [英] Why is the GUID structure declared the way it is?

问题描述

在rpc.h中，GUID结构声明如下:

In rpc.h, the GUID structure is declared as follows:

typedef struct _GUID 
{  
   DWORD Data1;  
   WORD Data2;  
   WORD Data3;  
   BYTE Data[8];
} GUID;

我了解Data1，Data2和Data3.当写出GUID(XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXX)时，它们定义了第一，第二和第三组十六进制数字.

I understand Data1, Data2, and Data3. They define the first, second, and third sets of hex digits when writing out a GUID (XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXX).

我从未理解过，为什么最后两个组在同一个字节数组中一起声明.这样会更有意义(并且更容易编写代码)吗?

What I never understood was why the last 2 groups were declared together in the same byte array. Wouldn't this have made more sense (and been easier to code against)?

typedef struct _GUID 
{  
   DWORD Data1;  
   WORD Data2;  
   WORD Data3;  
   WORD Data4;  
   BYTE Data5[6]; 
} GUID;

有人知道为什么这样声明吗?

Anyone know why it is declared this way?

推荐答案

这是因为GUID是 RFC 4122 .

It's because a GUID is a special case of a UUID. For information on what all the fields mean, you can look at RFC 4122.

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