Hi, I compile my project with boost header only files, the compiler is C6000 Texas Instruments. The compile errors occurs for example in "boost/algorithm/string/find_iterator.hpp" I have extracted the cause of the problem in the next example code: namespace boost { namespace iterators { class iterator_core_access { public: iterator_core_access(){} ~iterator_core_access(){} }; } using iterators::iterator_core_access; } class testFriend { private: // don't work, compiler error: error: namespace "boost" has no actual member "iterator_core_access" friend class ::boost::iterator_core_access; // here is the problem // it works, compiles ok, this was my cure //friend class ::boost::iterators::iterator_core_access; }; int main () { // it works ::boost::iterator_core_access a; return 0; } Do you guys know what is the reason of this ? With msvc and g++ works fine. Thanks and best regards, Alin