C ++中的GUID默认值 [英] GUID default value in c++

问题描述

您好，我想在课堂上使用GUID.

1)我想在默认构造函数中给它一个默认值(例如0，NULL等).我该怎么办?

2)在另一个构造函数中，我想给它一个默认值，以防构造函数调用没有它的情况.例如:

构造函数:MY_CLASS(int a，int b，int c = 0，GUID g = ???)
调用:MY_CLASS m =新的MY_CLASS(5,3);

我该怎么办?

感谢

Hello, I want to use a GUID in my class.

1) I want to give it a default value in the default constructor (something like 0, NULL, etc). How can I do it?

2) In another constructor, I want to give it a default value in a case the call for the constructor dont have it. for example:

the constructor: MY_CLASS(int a, int b, int c = 0, GUID g = ???)
the call: MY_CLASS m = new MY_CLASS(5,3);

How can i do it?

Thanks

推荐答案

GUID的默认值:GUID_NULL或IID_NULL(它是GUID_NULL的别名)


GUID_NULL是设置为零的GUID.这是字符串表示形式''{00000000-0000-0000-0000-000000000000}''
typedef struct _GUID
{
无符号长型Data1;
无符号的简短Data2;
unsigned short Data3;
unsigned char Data4 [8];
} GUID;
const GUID GUID_NULL = {0，0，0，{0，0，0，0，0，0，0，0}};

Default value of a GUID: GUID_NULL, or IID_NULL (it is alias of GUID_NULL)


GUID_NULL is a GUID set to zero. Here''s a string representation ''{00000000-0000-0000-0000-000000000000}''
typedef struct _GUID
{
unsigned long Data1;
unsigned short Data2;
unsigned short Data3;
unsigned char Data4[8];
} GUID;
const GUID GUID_NULL = { 0, 0, 0, { 0, 0, 0, 0, 0, 0, 0, 0 } };

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