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why does guid have special formats? [duplicate]

This question already has answers here: Closed 11 years ago.

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Why is the GUID structure declared the way it is?

i've been looking a GUID generation开发者_StackOverflow中文版 and handling and is wondering why Microsoft has decided these "strange" formats.

A single format specifier that indicates how to format the value of this Guid. The format parameter can be "N", "D", "B", "P", or "X". If format is null or an empty string (""), "D" is used.

Say what?

Format flags goes as following:

N: 32 digits = 00000000000000000000000000000000

D: 32 digits separated by hyphens = 00000000-0000-0000-0000-000000000000

B: 32 digits separated by hyphens, enclosed in braces = {00000000-0000-0000-0000-000000000000}

P: 32 digits separated by hyphens, enclosed in parentheses = (00000000-0000-0000-0000-000000000000)

X: Four hexadecimal values enclosed in braces, where the fourth value is a subset of eight hexadecimal values that is also enclosed in braces = {0x00000000,0x0000,0x0000,{0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00}}

Why???

Why not a 00000000-00000000-00000000-00000000

or 0000-0000-0000-0000-0000-0000-0000-0000 ??

Does any one have a good answer, except its Microsoft? :o)


UUID/GUID have standard representations according to RFC-4122. Simpler explanation here.

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