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)
"bb047568-7252-4b1a-b39b-339c4cc464a6"
> (uuid-generate)
"825f3ed1-64c8-4779-93f6-36969eb0ebbf"

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)
"994c338b-c1d4-47bb-9f71-a9494c204323"
> (uuid-generate/random)
"700f7305-ee79-4d42-a8ae-107871b0d2ab"

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)
"63947786-5cfc-11f0-8b7e-83462163c402"
> (uuid-generate/time)
"6394b282-5cfc-11f0-8b7e-83462163c402"