How to Generate UUID in C++

How to Generate a UUID in C++

The most portable way to generate a UUID in C++ is Boost.UUID's random_generator, which produces a random, RFC 4122-compliant UUID v4 without depending on any OS-specific API. The r uuid reference explains how to use uuid::UUIDgenerate() for random v4 identifiers in R.

main.cpp

#include <boost/uuid/uuid.hpp>
#include <boost/uuid/uuid_generators.hpp>
#include <boost/uuid/uuid_io.hpp>
#include <iostream>

int main() {
    boost::uuids::random_generator gen;
    boost::uuids::uuid my_uuid = gen();

    std::cout << my_uuid << std::endl;
    // Output: 550e8400-e29b-41d4-a716-446655440000

    return 0;
}

Explanation

#include <boost/uuid/uuid.hpp> and #include <boost/uuid/uuid_generators.hpp> pull in the uuid type and the random_generator that builds one.
boost::uuids::random_generator gen; creates a callable generator object seeded from Boost's cryptographically secure random source.
gen() returns a boost::uuids::uuid — calling the generator like a function produces a new random v4 UUID on every call.
#include <boost/uuid/uuid_io.hpp> is what makes std::cout << my_uuid work; without it the compiler has no operator<< for the uuid type.

Convert a String to a UUID in C++

When a UUID arrives as a string — from a config file, command-line argument, or network payload — Boost's string_generator parses it back into a proper boost::uuids::uuid object. For uuid in rust in async web services, the page includes complete Actix-web and Axum handler examples.

main.cpp

#include <boost/uuid/uuid.hpp>
#include <boost/uuid/uuid_io.hpp>
#include <boost/uuid/string_generator.hpp>
#include <iostream>

int main() {
    boost::uuids::string_generator gen;
    boost::uuids::uuid u = gen("550e8400-e29b-41d4-a716-446655440000");

    std::cout << u << std::endl;

    return 0;
}

Explanation

boost::uuids::string_generator gen; builds a reusable parser object — construct it once and call it for as many strings as you need.
gen("550e8400-...") parses the hyphenated string form and returns a boost::uuids::uuid; it also accepts uppercase and unhyphenated 32-character hex strings.
Malformed input makes string_generator throw std::runtime_error, so wrap the call in a try/catch block when parsing untrusted data.
Two boost::uuids::uuid values compare equal with == whenever they represent the same identifier, regardless of how each one was created.

Other Options for Generating UUIDs in C++

Boost.UUID covers most projects, but if you'd rather skip the dependency, both major platforms expose a native UUID/GUID generator you can call directly instead.

platform-native.cpp

#ifdef _WIN32
#include <objbase.h>
#pragma comment(lib, "ole32.lib")

GUID my_guid;
CoCreateGuid(&my_guid);
#endif

#ifdef __linux__
#include <uuid/uuid.h>

uuid_t my_uuid;
char uuid_str[37];
uuid_generate(my_uuid);
uuid_unparse(my_uuid, uuid_str);
#endif

Explanation

CoCreateGuid() (Windows, <objbase.h>, requires linking ole32.lib) fills a GUID struct with a random 128-bit identifier using the OS's COM-based generator.
uuid_generate() (Linux, <uuid/uuid.h>, from the util-linux-dev / uuid-dev package) fills a 16-byte uuid_t array; uuid_unparse() formats it into the standard hyphenated string.
Both avoid the Boost dependency entirely, at the cost of portability — you'll need #ifdef guards, or a small wrapper, to support both platforms from one codebase.
Neither exposes namespace-based (v5) generation the way Boost's name_generator_sha1 does, so reach for Boost.UUID when you need deterministic, content-addressed IDs.

Generate UUID in C++

How to Generate a UUID in C++

Explanation

Convert a String to a UUID in C++

Explanation

Other Options for Generating UUIDs in C++

Explanation

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