libuuid

8.16.0.1

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)
"61d26643-6e45-4c45-b4b5-97db3a5f1b36"
> (uuid-generate)
"bb603f67-1e09-4077-b37a-2ffbbed96354"

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)
"7f6a3d64-cecc-4bdd-9418-abd2f20234ad"
> (uuid-generate/random)
"7954821e-fed7-48ba-92f6-f080aa373f22"

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)
"ab7ee896-d71f-11ef-abfc-4f796faeb2d2"
> (uuid-generate/time)
"ab7f1172-d71f-11ef-abfc-4f796faeb2d2"