Hi, the erase() method (defined in associative_ptr_container.hpp, line 104) seems a bit strange: size_type erase( const key_type& x ) // nothrow { BOOST_ASSERT( !this->empty() ); iterator i = find( x ); // nothrow if( i == this->end() ) // nothrow return 0; // nothrow this->remove( i ); // nothrow return this->c_private().erase( i.base() ); // nothrow } http://cvs.sourceforge.net/viewcvs.py/boost/boost/boost/ptr_container/detail/associative_ptr_container.hpp?rev=1.4&view=markup My compiler (vc++7.1) complained about the unknown find() when I called erase() on ptr_map. "find" is not declared neither in this class nor in its base class. The closest valid call I could think of would be this->c_private().find( x ) . But there seems to be a nicer solution: size_type erase( const key_type& x ) // nothrow { BOOST_ASSERT( !this->empty() ); return this->c_private().erase( x ); // nothrow } This compiles fine and does just what I want it to do, even nothrow is guaranteed (I checked the vc++ reference for std::map). Now I wonder why erase() is implemented differently in Boost 1.33. Is there anything I overlooked? Btw, is there a rationale for the declaration of insert()? std::pair<iterator,bool> insert( key_type& k, value_type x ); http://cvs.sourceforge.net/viewcvs.py/boost/boost/boost/ptr_container/ptr_map_adapter.hpp?rev=1.12&view=auto Passing key_type by non-const reference caused some unaesthetic constructs in my code because return values (temporaries) cannot be used directly. Malte