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)
"5c3b13bb-716b-4d23-96dd-db742d344038"
> (uuid-generate)
"93ac941e-2038-4e30-a3b7-e06410e1a1bf"

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)
"afbbf266-4db2-435f-b6f8-49cc53d23301"
> (uuid-generate/random)
"60cd844a-c9bd-433a-b2ac-311e95e2ac53"

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)
"d3b08544-7f4f-11f0-b6e6-61381789e625"
> (uuid-generate/time)
"d3b0a8b2-7f4f-11f0-b6e6-61381789e625"