libuuid

8.16.0.4

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)
"7f411a34-e8d9-40ff-a0fa-5d51a85fa6b5"
> (uuid-generate)
"3d9572ad-163d-4185-9ed1-19b85896eb5e"

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)
"5ad2890b-8b55-46f6-b6ab-031b21ea6900"
> (uuid-generate/random)
"adb98c14-ae19-40c4-a6e6-cc6defed971e"

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)
"831df33c-0efc-11f0-b1b6-cb16545690b2"
> (uuid-generate/time)
"831e1e84-0efc-11f0-b1b6-cb16545690b2"