Hi. I have the following problem: One of our devs used (my_opt != NULL) to check an boost::optional for emptiness. This lead me to write the following test case: ... using namespace std; boost::optional<int> num_opt; boost::optional< std::string > obj_opt; if(obj_opt) { cout << "(3) Object: " << *obj_opt << endl; } // Compiles and does what the user intended - // BUT is this what the boost optional interface intends?? - // namely checking the optional for empty: if(obj_opt != NULL) { cout << "(4) Object: " << *obj_opt << endl; } if(num_opt) { cout << "(1) Integer: " << *num_opt << endl; } // Compiles and crashes, because the user actually // should have written if(num_opt) but, being used to pointers, // wrote the below, which compiles fine, but does not check for empty // but for equality with zero: if(num_opt != NULL) { cout << "(2) Integer: " << *num_opt << endl; } ... I find the behaviour of boost::optional<int> vs. opt<ClassType> highly un-intuitive. Wouldn't it be better if comparing an boost::optional always required to "dereference" it? I checked the headers (Boost 1.44) and sadly there doen't seem to be a preprocessor switch to disable the implicit comparison operators ... I would appreciate if other users could comment on my observations. Thanks! cheers, Martin