El 27/01/2013 9:02, Matias Capeletto escribió:
Any attempt to use the offset of the member to get to the bimap class seems to be forbidden by the standard.
Yes, i'ts undefined behaviour in theory but not in practice. Boost.Intrusive has a useful function implemented for many compilers: http://www.boost.org/doc/libs/1_52_0/boost/intrusive/parent_from_member.hpp It's similar to a "downcast" but using members. Like "static_cast", it does not work with virtual inheritance. In your case the pointer to member value can be a compile-time constant (so &Bimap::left can be passed as a template parameter). This constant can be part of the type "left_map" or the compile-time pointer to member could be obtained by left_map by a metafunction, call parent_from_member passing "this" and the compile-time pointer to member value, obtaining the pointer to Bimap. This way you can avoid storing any pointer to Bimap into left_map. Best, Ion