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)
"d6da0e10-d601-41e5-a7a6-1da931d44574"
> (uuid-generate)
"cfb4a212-7728-428e-87bd-c1a076f4ad4a"

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)
"023d8e55-314d-46eb-9a87-8b06d929a34a"
> (uuid-generate/random)
"4afd00a4-7376-4ce0-a831-a6a465f6776e"

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)
"b5712456-a60c-11f0-a29d-511616cfbc78"
> (uuid-generate/time)
"b5714800-a60c-11f0-a29d-511616cfbc78"