NFD » ndn-cxx

This Feature is correct but not important.

Once either function is invoked, app stops receiving Interests because handler is removed from Face's internal FIB.

App doesn't care when NFD's Route is unregistered.

There is a potential problem of not having the callback. Operations are async (=they are scheduled in IO thread).

If the app is written that it destroys the face or the corresponding callback just after the call to unregisterPrefix/unsetInterestFilter, there is still a chance of the callback to be dispatched which can result in segfault.

I agree that this feature is low priority, but would be good to have.

It seems that Face::unregisterPrefix already has success/failure callbacks. An Face::unsetInterestFilter overload does not have success/failure callbacks, but its implementation is exactly same as Face::unregisterPrefix.
How about deprecating Face::unsetInterestFilter overload in favor of Face::unregisterPrefix?

If the app is written that it destroys the face or the corresponding callback just after the call to unregisterPrefix/unsetInterestFilter, there is still a chance of the callback to be dispatched which can result in segfault.

I cannot reproduce this situation. valgrind isn't complaining on the snippet below. I guess ndn-cxx:commit:ae0b418784aa1b021797190d0e56abb95a386b3c has fixed the problem.

// g++ -o x -std=c++0x x.cpp $(pkg-config --cflags --libs libndn-cxx)
#include <ndn-cxx/face.hpp>
#include <boost/asio.hpp>

using namespace ndn;

int main()
{
  boost::asio::io_service io;
  Face* face = new Face(io);
  const RegisteredPrefixId* rpid = face->registerPrefix("/A",
    bind([] { std::cout << "register-success\n"; }),
    bind([] { std::cout << "register-failure\n"; }));
  face->processEvents(time::milliseconds(500));
  face->unregisterPrefix(rpid,
    bind([] { std::cout << "unregister-success\n"; }),
    bind([] { std::cout << "unregister-failure\n"; }));
  delete face;
  io.run();
  return 0;
}