I still occasionally find myself reflexively std::move()ing strings into glibmm/gtkmm functions that I unconsciously see as taking ownership of their arguments - only to realise it makes no difference because all of them take strings as const&.This made me wonder whether there are any cases where, if the user instructs so by using std::move(), glibmm/gtkmm functions could steal the string [ or at least it's c_str() ] and thus avoid having to copy it. All those copies quickly add up to a lot.