[boost] [serialization] use of unsigned int instead of size_type

File collections_save_imp.hpp uses unsigned int to represent number of elements in STL container. Shouldn't this be replaced with "typename Container::size_type" (or at least with size_t) to be more portable? At least it would stop annoying warning from MSVC. The part of file that is relevant: template<class Archive, class Container> inline void save_collection(Archive & ar, const Container &s) { // record number of elements unsigned int count = s.size(); // <-- here and also below ar << make_nvp("count", const_cast<const unsigned int &>(count)); /* ...truncated... */ Best regards, Marcin