Data::UUID::LibUUID - uuid.h based UUID generation (versions 2 and 4 depending on platform)

Author

       Yuval Kogman <nothingmuch@woobling.org>

Copyright

           Copyright (c) 2008 Yuval Kogman. All rights reserved
           This program is free software; you can redistribute
           it and/or modify it under the same terms as Perl itself.

perl v5.40.0                                       2024-10-20                           Data::UUID::LibUUID(3pm)

Description

       This module provides bindings for libuuid shipped with e2fsprogs or uuid-dev on debian, and also works
       with the system uuid.h on darwin.

Exports

new_uuid_string $version
new_uuid_binary $version
Returns a new UUID in string (dash separated hex) or binary (16 octets) format.

$version can be either 2, or 4 and defaults to whatever the underlying implementation prefers.

Version 1 is timestamp/MAC based UUIDs, like Data::UUID provides. They reveal time and host
information, so they may be considered a security risk.

Version 2 is described here
<http://www.opengroup.org/onlinepubs/9696989899/chap5.htm#tagcjh_08_02_01_01>. It is similar to
version 1 but considered more secure.

Version 4 is based just on random data. This is not guaranteed to be high quality random data, but
usually is supposed to be.

On MacOS X "getpid" is called before UUID generation, to ensure UUIDs are unique accross forks.
Behavior on other platforms may vary.

uuid_to_binary $str_or_bin
Converts a UUID from string or binary format to binary format.

Returns undef on a non UUID argument.

uuid_to_string $str_or_bin
Converts a UUID from string or binary format to string format.

Returns undef on a non UUID argument.

uuid_eq $str_or_bin, $str_or_bin
Checks if two UUIDs are equivalent. Returns true if they are, or false if they aren't.

Returns undef on non UUID arguments.

uuid_compare $str_or_bin, $str_or_bin
Returns -1, 0 or 1 depending on the lexicographical order of the UUID. This works like the "cmp"
builtin.

Returns undef on non UUID arguments.

new_dce_uuid_string
new_dce_uuid_binary
These two subroutines are a little hackish in that they take no arguments but also do not validate
the arguments, so they can be abused as methods:

package MyFoo;

use Data::UUID::LibUUID (
new_dce_uuid_string => { -as "generate_uuid" },
);

sub yadda {
my $self = shift;
my $id = $self->generate_uuid;
}

This allows the ID generation code to be subclassed, but still keeps the hassle down to a minimum.
DCE is UUID version two specification.

ascending_ident
Creates a lexically ascending identifier containing a UUID, high resolution timestamp, and a counter.

This is not a UUID (it's longer), but if you can store variable length identifier (and exposing the
system clock is not an issue) they can be used to create an identifier that is both universally
unique, and lexically increasing.

Note that while the identifiers are universally unique, there is no universal ordering (that would
require synchronization), so identifiers generated on different machines or even different
process/thread could have IDs which interleave.

Name

       Data::UUID::LibUUID - uuid.h based UUID generation (versions 2 and 4 depending on platform)

Synopsis

           use Data::UUID::LibUUID;

           my $uuid = new_uuid_string();

Todo

       •   Consider bundling libuuid for when no system "uuid.h" exists.

Version Control

       This    module    is    maintained    using    Darcs.    You    can   get   the   latest   version   from
       <http://nothingmuch.woobling.org/code>, and use "darcs send" to commit changes.