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)
"03be31d6-1a04-4869-8d77-a5de2258746f"
> (uuid-generate)
"c13a8350-3d4b-44f9-ad67-f957457a2d8d"

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)
"9986b96e-7ca8-43ef-b875-137215fc8a3b"
> (uuid-generate/random)
"5968c07d-bc0f-42a2-a897-3040a2b9ca60"

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)
"7c454614-bb9f-11f0-b9e5-558125cc0d17"
> (uuid-generate/time)
"7c454cea-bb9f-11f0-b9e5-558125cc0d17"