UUID

Overview

Universally Unique Identifiers (UUID), also known as Globally Unique IDentifiers (GUIDs), are 128-bit identifiers intended to guarantee uniqueness across space and time. They are defined by RFC 9562.

The UUID subsystem provides utility functions for the generation, parsing, and manipulation of UUIDs. It supports generating version 4 (random) and version 5 (name-based) UUIDs.

Usage

To use the UUID API, include the header file:

#include <zephyr/sys/uuid.h>

Generating a UUIDv4

UUIDv4 is based on random numbers (hence requires an entropy generator), and can be generated using the uuid_generate_v4() function. CONFIG_UUID_V4 must also be enabled.

struct uuid my_uuid;
char uuid_str[UUID_STR_LEN];

int ret = uuid_generate_v4(&my_uuid);

if (ret != 0) {
    printk("Failed to generate UUID v4 (err %d)\n", ret);
    return ret;
}

ret = uuid_to_string(&my_uuid, uuid_str);
if (ret != 0) {
    printk("Failed to convert UUID to string (err %d)\n", ret);
    return ret;
}

 printk("UUID: %s\n", uuid_str);

Generating a UUIDv5

UUIDv5 is generated from a namespace UUID and a name (binary data), and can be generated using the uuid_generate_v5() function. CONFIG_UUID_V5 must also be enabled.

UUIDv5 is deterministic: the same namespace and name will always result in the same UUID.

struct uuid ns_uuid;
struct uuid my_uuid;
char uuid_str[UUID_STR_LEN];

/* Well-known namespace ID for URLs (RFC 9562) */
uuid_from_string("6ba7b811-9dad-11d1-80b4-00c04fd430c8", &ns_uuid);

const char *name = "https://zephyrproject.org/";
int ret = uuid_generate_v5(&ns_uuid, name, strlen(name), &my_uuid);

if (ret != 0) {
    printk("Failed to generate UUID v5 (err %d)\n", ret);
    return ret;
}

ret = uuid_to_string(&my_uuid, uuid_str);
if (ret != 0) {
    printk("Failed to convert UUID to string (err %d)\n", ret);
    return ret;
}

/* outputs: "UUID: abdb72b5-b342-5882-925b-4ce0e3cb4790" */
printk("UUID: %s\n", uuid_str);

Configuration

Related configuration options:

API Reference

UUID