[boost] confused about uniform_01

I'm confused. Usually I want to share the state of 1 underlying rng between many distributions, to ensure good independence. So, for example: boost::variate_generator<rng_t&, boost::uniform_real<> > gen; But uniform_01 holds a rng member: base_type _rng; which is not declared as a reference. But, I _can't_ make it a reference, by doing: boost::uniform_01<rng_t&> eng; Because uniform_01 says: base_type& base() { return _rng; } Which would then be && and won't compile. What am I not understanding?