libuuid

8.17.0.4

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)
"e6e17a59-bb37-4398-a230-e83dbc3c5ccd"
> (uuid-generate)
"a103326c-d363-437b-b1b0-12414626bf71"

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)
"91b3b22f-217b-4afa-86ac-a2f1c6d613d3"
> (uuid-generate/random)
"2597e3de-7867-4147-b0e0-2b7519aba384"

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)
"f3508778-40d4-11f0-87d7-074b12218d62"
> (uuid-generate/time)
"f350ab18-40d4-11f0-87d7-074b12218d62"