libuuid

8.16.900

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)
"97151746-730e-4381-b2af-151ea70550ce"
> (uuid-generate)
"ed4fb5cc-28d1-442a-966a-75679833f80d"

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)
"6a7074e8-8510-45ed-8d67-ac94475fe0e3"
> (uuid-generate/random)
"2c73efa6-12aa-4341-b866-957c2d078da1"

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)
"19d383fa-3301-11f0-a544-d3a6e1a3e6d7"
> (uuid-generate/time)
"19d3aa6a-3301-11f0-a544-d3a6e1a3e6d7"