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)
"c58de149-1ab8-4f38-a3e3-9296692d4267"
> (uuid-generate)
"3d07bf47-36ff-4444-acfd-ea1ed70a5d92"

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)
"0d17224f-96d0-472f-a00a-52f21ecfd852"
> (uuid-generate/random)
"2f8d28e7-4b71-4bd6-a3cd-b08ab2f684b1"

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)
"ff52197c-5e54-11f0-98c5-4310d5b6cc3b"
> (uuid-generate/time)
"ff528d08-5e54-11f0-98c5-4310d5b6cc3b"