I'm building Boost 1.47.0 with GCC 4.6.1 and C++11 support enabled and get the following two errors building the Signals library: libs/signals/src/named_slot_map.cpp: In member function ‘void boost::signals::detail::named_slot_map::disconnect(const boost::signals::detail::stored_group&)’: libs/signals/src/named_slot_map.cpp:105:23: error: call of overloaded ‘erase(boost::signals::detail::named_slot_map::group_iterator&)’ is ambiguous libs/signals/src/named_slot_map.cpp:105:23: note: candidates are: /usr/local/include/c++/4.6.1/bits/stl_map.h:613:7: note: std::map<_Key, _Tp, _Compare, _Alloc>::iterator std::map<_Key, _Tp, _Compare, _Alloc>::erase(std::map<_Key, _Tp, _Compare, _Alloc>::const_iterator) [with _Key = boost::signals::detail::stored_group, _Tp = std::listboost::signals::detail::connection_slot_pair, _Compare = boost::function2, _Alloc = std::allocatorboost::signals::detail::connection_slot_pair > >, std::map<_Key, _Tp, _Compare, _Alloc>::iterator = std::_Rb_tree_iteratorboost::signals::detail::connection_slot_pair > >, std::map<_Key, _Tp, _Compare, _Alloc>::const_iterator = std::_Rb_tree_const_iteratorboost::signals::detail::connection_slot_pair > >] /usr/local/include/c++/4.6.1/bits/stl_map.h:643:7: note: std::map<_Key, _Tp, _Compare, _Alloc>::size_type std::map<_Key, _Tp, _Compare, _Alloc>::erase(const key_type&) [with _Key = boost::signals::detail::stored_group, _Tp = std::listboost::signals::detail::connection_slot_pair, _Compare = boost::function2, _Alloc = std::allocatorboost::signals::detail::connection_slot_pair > >, std::map<_Key, _Tp, _Compare, _Alloc>::size_type = long unsigned int, std::map<_Key, _Tp, _Compare, _Alloc>::key_type = boost::signals::detail::stored_group] libs/signals/src/named_slot_map.cpp: In member function ‘void boost::signals::detail::named_slot_map::remove_disconnected_slots()’: libs/signals/src/named_slot_map.cpp:128:35: error: call of overloaded ‘erase(std::_Rb_tree_iteratorboost::signals::detail::connection_slot_pair > >::_Self)’ is ambiguous libs/signals/src/named_slot_map.cpp:128:35: note: candidates are: /usr/local/include/c++/4.6.1/bits/stl_map.h:613:7: note: std::map<_Key, _Tp, _Compare, _Alloc>::iterator std::map<_Key, _Tp, _Compare, _Alloc>::erase(std::map<_Key, _Tp, _Compare, _Alloc>::const_iterator) [with _Key = boost::signals::detail::stored_group, _Tp = std::listboost::signals::detail::connection_slot_pair, _Compare = boost::function2, _Alloc = std::allocatorboost::signals::detail::connection_slot_pair > >, std::map<_Key, _Tp, _Compare, _Alloc>::iterator = std::_Rb_tree_iteratorboost::signals::detail::connection_slot_pair > >, std::map<_Key, _Tp, _Compare, _Alloc>::const_iterator = std::_Rb_tree_const_iteratorboost::signals::detail::connection_slot_pair > >] /usr/local/include/c++/4.6.1/bits/stl_map.h:643:7: note: std::map<_Key, _Tp, _Compare, _Alloc>::size_type std::map<_Key, _Tp, _Compare, _Alloc>::erase(const key_type&) [with _Key = boost::signals::detail::stored_group, _Tp = std::listboost::signals::detail::connection_slot_pair, _Compare = boost::function2, _Alloc = std::allocatorboost::signals::detail::connection_slot_pair > >, std::map<_Key, _Tp, _Compare, _Alloc>::size_type = long unsigned int, std::map<_Key, _Tp, _Compare, _Alloc>::key_type = boost::signals::detail::stored_group] WHOA BUDDY! Anyway, if you look into this, it is because my STL implementation has changed to the new definition for map::erase which takes a const_iterator. As you can see, trying to erase with an iterator creates an ambiguous call between the const_iterator and key_type. I came up with two solutions: One was to explicitly cast to a const_iterator and the other was to mark stored_group::stored_group<T>(const T&) as explicit. Both work perfectly fine for me, but I like the explicit constructor solution better. I attached that change as a patch...feel free to use it if it doesn't break anything (which it probably does). -- Travis Gockel