Re: [Boost-users] Re: boost::bind and member functions

Pablo Aguilar wrote:

Maybe not the best solution performance-wise, but you can try the following:

Replace typedef float (A::*pfn)(int, float); with typedef boost::function3 pfn;

Thanks, that works nicely, though the required coding difference is a bit disconcerting. I found that if I created a class in analogy with "apply" called, say, "apply_mem_fn" like this: namespace boost { template<class R> struct apply_mem_fn { typedef R result_type; template result_type operator()(F & f, A1 & a1, A2 & a2, A3 & a3) const { return ((a1).*(f))(a2, a3); } }; } // namespace boost Then I can achieve what I was trying to accomplish with code that looks nearly the same as in the case of pointers to non-member functions: #include <vector> #include <iostream> #include <iterator> #include "boost/bind.hpp" namespace boost { template<class R> struct apply_mem_fn { typedef R result_type; template result_type operator()(F & f, A1 & a1, A2 & a2, A3 & a3) const { return ((a1).*(f))(a2, a3); } }; } // namespace boost using namespace std; using namespace boost; struct A { float a(int m, float x) { return m * x;} float b(int m, float x) { return m + x;} float c(int m, float x) { return m - x;} float d(int m, float x) { return m / x;} }; typedef float (A::*pfn)(int, float); int main() { A a; int m = 2; float x = 3.0; vector<pfn> v; vector<float> f; v.push_back(&A::a); v.push_back(&A::b); v.push_back(&A::c); v.push_back(&A::d); transform(v.begin(), v.end(), back_inserter(f), bind(apply_mem_fn<float>(), _1, a, m, x)); copy(f.begin(), f.end(), ostream_iterator<float>(cout, "\n")); } It's not clear to me whether it's possible to choose the right implementation based on the argument. Dave