libuuid

8.17

libuuid🔗ℹ

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

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)
"d086a9f3-8af6-497a-ab6b-e440b5e6c2bf"
> (uuid-generate)
"d3917994-d561-476d-922a-3483ad6d8cd2"

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)
"be36c5e2-e196-4746-a968-926fdb36f23c"
> (uuid-generate/random)
"77b1567b-a37d-4d4f-b8a3-fb02eb88b1de"

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)
"5663a228-3153-11f0-ba94-cd897bf497c8"
> (uuid-generate/time)
"5663af20-3153-11f0-ba94-cd897bf497c8"