boost uuid

UUIDs are used by distributed systems that have to uniquely identify components. For example, Microsoft uses UUIDs to identify interfaces in the COM world. For new interfaces developed for COM, unique identifiers can be easily assigned.

UUIDs are 128-bit numbers. Various methods exist to generate UUIDs. For example, a computer’s network address can be used to generate a UUID. The generators provided by Boost.Uuid are based on a random number generator to avoid generating UUIDs that can be traced back to the computer generating them.

1. boost::uuids::random_generator

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

using namespace boost::uuids;

int main()
{
  random_generator gen;
  uuid id = gen();
  std::cout << id << std::endl;

  std::cout << id.size() << std::endl;
  std::cout << std::boolalpha << id.is_nil() << std::endl;
  std::cout << id.variant() << std::endl;
  std::cout << id.version() << std::endl;

return 0; }

size() returns the size of a UUID in bytes. Because a UUID is always 128 bits, size() always returns 16. is_nil() returns true if the UUID is a nil UUID. variant() and version() specify the kind of UUID and how it was generated.

2. conversion to strings

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

using namespace boost::uuids;

int main()
{
  random_generator gen;
  uuid id = gen();

  std::string s = to_string(id);
  std::cout << s << std::endl;

  std::cout << boost::lexical_cast<std::string>(id) << std::endl;

  return 0;
}

uses boost::uuids::to_string() or boost::lexical_cast()