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)
"684bf9d0-dee8-4a59-8b0d-aedfcfa3ca30"
> (uuid-generate)
"b060cf4e-756f-40c0-9299-5350f1961a5f"

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)
"59eb16fe-cd21-4f6a-a336-dcd9080ef8d8"
> (uuid-generate/random)
"9975e178-a788-427d-b270-b829f73f48be"

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)
"f2a36b5c-c7b0-11f0-be85-3bd6b9238645"
> (uuid-generate/time)
"f2a38362-c7b0-11f0-be85-3bd6b9238645"