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)
"2a01a8d2-b9ee-40ea-9c54-32aa5e5e8ab2"
> (uuid-generate)
"aab4d680-f689-4159-beb4-2c41d2a46729"

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)
"4547b667-141a-4012-8e3a-860a3e0ee006"
> (uuid-generate/random)
"97b537f5-022f-4d15-aaf6-129b1ede3a43"

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)
"9e9af182-cea5-11f0-b914-15b9726aa6cf"
> (uuid-generate/time)
"9e9af88a-cea5-11f0-b914-15b9726aa6cf"