libuuid
uuid-generate
uuid-generate/  random
uuid-generate/  time
8.2

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)

"5d65b5e0-1d70-45bd-9574-a8a56486"

> (uuid-generate)

"ecb6a51b-00b0-4b61-9e09-3ae57c01"

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)

"150bde83-14fa-4dbd-95ec-3321dd08"

> (uuid-generate/random)

"4e0be3fd-2c26-44b7-bebf-65d27e8c"

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)

"984d5a9e-e8be-11eb-b049-c91e7154"

> (uuid-generate/time)

"984d6d22-e8be-11eb-b049-c91e7154"