I am getting compiler error using boost::function and boost::numeric::ublas as function return value. I am sure I am not declaring something right, but I can't quite catch where (probably the "const" member function specifier). Any help will be greatly appreciated. Code to reproduce the problem is shown below. If #include <vector> #include <boost/function.hpp> #include <boost/numeric/ublas/matrix.hpp> using namespace boost::numeric::ublas; class Foo { public: int bar() const { return 1; } const matrix<double>& stdev() const { return _stdev; } private: matrix<double> _stdev; }; typedef std::vector<Foo> container; class invoker { public: invoker (container* cont, boost::function<int (Foo*) > t) : f(t), _cont(cont) { for (container::iterator it = _cont->begin(); it != _cont->end(); ++it) { Foo& foo = *it; int i = f(&foo); } } // compiler generates error if following code // is uncomennted together with the call in _tmain // invoker (container* cont, // boost::function<const matrix<double>& (Foo* const) > fmatrix) // : _fmatrix(fmatrix), _cont(cont) // { // for (container::iterator it = _cont->begin(); // it != _cont->end(); ++it) // { // Foo& foo = *it; // const matrix<double>& stddev = _fmatrix(&foo); // } // } private: boost::function<int (Foo*) > f; boost::function<const matrix<double>& (Foo* const) > _fmatrix; container* _cont; }; int _tmain(int argc, _TCHAR* argv[]) { container lst (5); std::fill(lst.begin(), lst.begin() + 5, Foo()); invoker invbar(&lst, &Foo::bar); // uncomment this line together with method in "invoker" to generate error // invoker invstdev(lst, &Foo::stdev); return 0; }