libuuid
uuid-generate
uuid-generate/  random
uuid-generate/  time
7.5

libuuid

Jan Dvorak <mordae@anilinux.org>

Interface to the libuuid library usable to generate high-quality UUIDs.

 (require libuuid) package: libuuid

procedure

(uuid-generate)  string?

Generate new universally unique identifier using /dev/urandom, if available. If it is not available, use current time, local ethernet MAC address and random data from a pseudo-random generator.

Examples:
> (uuid-generate)

"d5bca603-85ac-4090-b0cc-ea851a8110f8"

> (uuid-generate)

"e12651f8-37b9-40ae-ad0b-34e2bdc2b79c"

procedure

(uuid-generate/random)  string?

When /dev/urandom is available, same as uuid-generate, but fails back to a pseudo-random generator only.

Can be used to prevent any chance of host’s MAC address leaking, at the cost of slightly higher chance of generating non-unique identifiers if the worst-case situation arises on multiple hosts.

Examples:
> (uuid-generate/random)

"b2fd64cb-3523-4a4f-b50c-b2ed35672c8e"

> (uuid-generate/random)

"2267c7c6-4c92-44f6-a77b-dbfc5c11735b"

procedure

(uuid-generate/time)  string?

Same as uuid-generate when the /dev/urandom is missing.

Could potentially produce non-uniqueue identifiers if used concurrently so if you do not absolutely need sequential identifiers, stick with the generic (and safe) uuid-generate function above.

Examples:
> (uuid-generate/time)

"7991db06-0e82-11ea-b02f-2d08393ef337"

> (uuid-generate/time)

"799201e4-0e82-11ea-b02f-2d08393ef337"