Racket

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)
"5a82af85-8df5-4114-8bb6-1bd38351e2b8"
> (uuid-generate)
"8d5c6124-bb18-41b3-929b-b1faf4e9c8d6"

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)
"260ca969-7b47-4532-84f7-e46ec5b91592"
> (uuid-generate/random)
"d98dc4d8-0ea8-431b-bae0-1d6da24ca655"

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)
"bfdc35b2-4ead-11f1-9c4d-5520a19489b3"
> (uuid-generate/time)
"bfdc3f94-4ead-11f1-9c4d-5520a19489b3"