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)
"34cc075c-32df-4f95-b1b6-d2637faa0b50"
> (uuid-generate)
"1bbff251-87e9-4b2a-b674-9ed1e5bc2564"

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)
"f2d9fb6b-fb18-471b-88d6-91cc3a69ebe4"
> (uuid-generate/random)
"253eb831-4fd5-4d11-bbf5-9bc5f52e0cc6"

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)
"f353b712-b709-11f0-bbd9-cb9c404e1357"
> (uuid-generate/time)
"f353bd52-b709-11f0-bbd9-cb9c404e1357"