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)
"185e9485-501d-4567-8b53-15adcef0e886"
> (uuid-generate)
"2dd9cce3-cfbc-4f2f-83e8-c99d8130f731"

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)
"4c6a4e60-a126-4b16-ab44-26d0bfb8302b"
> (uuid-generate/random)
"3640657a-444f-4417-a32b-96b6141ca34f"

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)
"b6160ee8-a5b8-11f0-a5cd-f39b95b507fb"
> (uuid-generate/time)
"b616150a-a5b8-11f0-a5cd-f39b95b507fb"