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)
"9f5aa0c7-26f5-4aa7-86bc-ba001a064990"
> (uuid-generate)
"3026e9d9-e15a-473e-9e48-57a52c8a5ece"

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)
"66336f22-fb58-4400-a137-a8ecc240e303"
> (uuid-generate/random)
"9ecdfeb2-1f01-4a66-85d4-48efbc34a468"

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)
"54e57d8e-8038-11f0-b068-493ba8dc208a"
> (uuid-generate/time)
"54e5b4c0-8038-11f0-b068-493ba8dc208a"