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)
"771689de-cb61-4121-89f0-55e3706b6e9e"
> (uuid-generate)
"d20ef740-78d2-4455-a676-08963fd12254"

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)
"b207c04b-f4fd-4497-863a-30a179ec8fde"
> (uuid-generate/random)
"f84f9aaf-bf3e-4fc7-8ef4-bfec995032ab"

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)
"e141f2c0-6f2c-11f0-842b-cd37d53529d2"
> (uuid-generate/time)
"e142171e-6f2c-11f0-842b-cd37d53529d2"