[Boost-users] static reflection

On a boost thread a while ago, I saw some code to query for the existence of a member function of a class using SFINAE and BOOST_STATIC. I guess you could call it static reflection. Below is a code snippet that does not work using the aforementioned methods. The culprit is the using Base::operator() statement in the Derived class. Apparently the base class method void operator()(float u) is not part of the type of Derived. This was a shock to me, because you can call the overloaded method from the derived class. I'd appreciate any advice on how to check for the existence of member functions in this scenario. I fear it may be impossible. Thanks! #include <iostream> #include typedef char (&no_tag)[1]; typedef char (&yes_tag)[2]; template struct HasExactSignature { }; template no_tag doesVisitorImplementHelper(...); template yes_tag doesVisitorImplementHelper(HasExactSignature* p=0); template struct DoesVisitorImplement { BOOST_STATIC_CONSTANT(bool, value = sizeof(doesVisitorImplementHelper(0)) == sizeof(yes_tag)); }; struct Base { void operator()(float u) { std::cout << "aaaa"; } }; struct Derived : public Base { using Base::operator(); void operator()(int u) { std::cout << "bbbb"; } }; int main() { std::cout << DoesVisitorImplement::value << std::endl; std::cout << DoesVisitorImplement::value << std::endl; return 0; }