Hi boosters, First of all, my opinion is that this kind of classes, sometimes called concrete types, are the very plus plus suggested by the language's name. A well designed user type behaves and cost, exactly the same as any built in type. This makes C++ unique in the plethora of available languages. That said, I must mention that I am aware of the flaws pointed out by many reviewers, specially those concerning interface. In particular, I don't like the "default null constructor". For me, the default constructor MUST generate a valid object, period. I have already copied/used Andy's code, which I luckily found in your vault, and one thing I changed was this default constructor [uuid_t uuid; // generates a valid random uuid]. If the user is short of resources, she must use the copy constructor [uuid_t nil(uuid_t::null());]. But I don't provide a bool is_null() const; method, for operator==() does the job pretty well. Despite this weaknesses, I think the library is ready for out-of-the-box usage, so my vote is YES, this library should be part of boost. Sincerely, Kenneth -- View this message in context: http://www.nabble.com/-Review--UUID-library-%28mini-%29review-starts-today%2... Sent from the Boost - Users mailing list archive at Nabble.com.