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)
"3fccb2bc-6f71-4335-9bff-78932776229e"
> (uuid-generate)
"b35fb948-fb07-4ea9-a722-162f0fd6c52e"

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)
"0e49eef4-34d1-443b-82e0-1e0c8e55cb0d"
> (uuid-generate/random)
"0a21e611-5117-48c8-a8ce-6d56aa360c19"

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)
"1f40d394-5f1e-11f0-a602-2bec95abfc4d"
> (uuid-generate/time)
"1f41da78-5f1e-11f0-a602-2bec95abfc4d"