I've just started working on my first project trying to fully utilize STL and the boost libraries, and have already run into something that I can't seem to figure out... I'm trying to use find_if to check if a member function of an object contained in an array returns true. It will only return true for a single object in the collection, so I just need the first instance. When the vector is declared like this: vector col; This statement compiles... vector::const_iterator i = find_if(col.begin(),col.end(),mem_fun(&Widget::IsPrimary)); However, when I try to use the boost::shared_ptr library like so... typedef boost::shared_ptr<Widget> WidgetPtr; vector<WidgetPtr> col; This statement causes gcc to bark with all manner of errors... vector<WidgetPtr>::const_iterator i = find_if(col.begin(),col.end(),mem_fun(&Widget::IsPrimary)); I'm thinking I've missed something basic, but it's eluding me...