[Boost-users] How to figure out if a boost class does lazy copy or not?

Hi, I need to construct some container in a function and return it. I think that some container in boost follow lazy copy sematics but some don't. For example, if tr1::unordered_map uses lazy copy, then I can return an object of tr1::unordered_map. Otherwise, I should return boost::shared_ptrtr1::unordered_map. Although this information may be documented for any container that I will use, I still think that it is still worthwhile to having my own test case to figure it out, because it may not easy to find such information in the document. I'm wondering if there is a generic way to test if a container use lazy copy or not without reading the actual implementation of the class? -- Regards, Peng