# UUIDs

UUIDs.uuid1Function
uuid1([rng::AbstractRNG]) -> UUID

Generates a version 1 (time-based) universally unique identifier (UUID), as specified by RFC 4122. Note that the Node ID is randomly generated (does not identify the host) according to section 4.5 of the RFC.

The default rng used by uuid1 is not GLOBAL_RNG and every invocation of uuid1() without an argument should be expected to return a unique identifier. Importantly, the outputs of uuid1 do not repeat even when Random.seed!(seed) is called. Currently (as of Julia 1.6), uuid1 uses Random.RandomDevice as the default rng. However, this is an implementation detail that may change in the future.

Julia 1.6

The output of uuid1 does not depend on GLOBAL_RNG as of Julia 1.6.

Examples

julia> rng = MersenneTwister(1234);

julia> uuid1(rng)
UUID("cfc395e8-590f-11e8-1f13-43a2532b2fa8")
UUIDs.uuid4Function
uuid4([rng::AbstractRNG]) -> UUID

Generates a version 4 (random or pseudo-random) universally unique identifier (UUID), as specified by RFC 4122.

The default rng used by uuid4 is not GLOBAL_RNG and every invocation of uuid4() without an argument should be expected to return a unique identifier. Importantly, the outputs of uuid4 do not repeat even when Random.seed!(seed) is called. Currently (as of Julia 1.6), uuid4 uses Random.RandomDevice as the default rng. However, this is an implementation detail that may change in the future.

Julia 1.6

The output of uuid4 does not depend on GLOBAL_RNG as of Julia 1.6.

Examples

julia> rng = MersenneTwister(1234);

julia> uuid4(rng)
UUID("7a052949-c101-4ca3-9a7e-43a2532b2fa8")
UUIDs.uuid5Function
uuid5(ns::UUID, name::String) -> UUID

Generates a version 5 (namespace and domain-based) universally unique identifier (UUID), as specified by RFC 4122.

Julia 1.1

This function requires at least Julia 1.1.

Examples

julia> rng = MersenneTwister(1234);

julia> u4 = uuid4(rng)
UUID("7a052949-c101-4ca3-9a7e-43a2532b2fa8")

julia> u5 = uuid5(u4, "julia")
UUID("086cc5bb-2461-57d8-8068-0aed7f5b5cd1")
UUIDs.uuid_versionFunction
uuid_version(u::UUID) -> Int

Inspects the given UUID and returns its version (see RFC 4122).

Examples

julia> uuid_version(uuid4())
4