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)
"08de953c-627e-4e66-a6dd-3bd54d255c4c"
> (uuid-generate)
"0fabfd50-8a36-4582-941e-69b22bbf5c1c"

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)
"6aab1cc0-9889-4a34-ac48-ffbf6c3b7618"
> (uuid-generate/random)
"3d9d260f-37e9-4409-bc67-218295a80255"

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)
"951d56de-b6bf-11f0-8ee4-f92e38ea87da"
> (uuid-generate/time)
"951d5d28-b6bf-11f0-8ee4-f92e38ea87da"