The UUID is assigned to an interface to distinguish that interface from other interfaces. The UUID is generated from a command-line utility program, uuidgen, which creates unique identifiers in the required format using both a time identifier and a machine identifier. It guarantees that any two UUIDs produced on the same machine are unique because they are produced at different times, and that any two UUIDs produced at the same time are unique because they are produced on different machines. The uuidgen utility generates the UUID in IDL file format or C-language format.
The textual representation of a UUID is a string consisting of 8 hexadecimal digits followed by a hyphen, followed by three hyphen-separated groups of 4 hexadecimal digits, followed by a hyphen, followed by 12 hexadecimal digits. The following example is a valid UUID string:
6B29FC40-CA47-1067-B31D-00DD010662DA
When you run the uuidgen utility from the command line, you can use the following command switches:
| uuidgen switch | Description |
|---|---|
| /i | Outputs UUID to an IDL interface template. |
| /s | Outputs UUID as an initialized C structure. |
| /o<filename> | Redirects output to a file; specified immediately after the /o switch. |
| /n<number> | Specifies the number of UUIDs to generate. |
| /v | Displays version information about uuidgen. |
| /h or ? | Displays command-option summary. |