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)
"1c12c674-7a61-45ef-a8b5-9fc6a78f5180"
> (uuid-generate)
"24d53677-1fff-452d-b3a1-6a4e2e9279bc"

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)
"c7d85692-afa3-4c25-9b43-e2a35bead9dc"
> (uuid-generate/random)
"eeb03f7c-e0c5-42fd-ba91-a10c26ab3967"

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)
"e3c3b622-40a6-11f1-b0dc-a78edbc52332"
> (uuid-generate/time)
"e3c3bcd0-40a6-11f1-b0dc-a78edbc52332"