Question

I would like to do a DNS reverse lookup (return hostname for a given IP Address) with asio, but I am not able to figure out which components I need to achieve this. Asio documentiation refers to ip::basic_resolver::resolve, but an endpoint_type is needed and I don’t know how to use it.
Could someone please post or refer to an example?

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EDIT:
With Joachim Pileborg’s help I was able to accomplish the task. Needed code (Minumin without error handling):

#include <asio.hpp>
#include <string>
#include <iostream>

int main()
{
    asio::ip::address_v4 ipa = asio::ip::address_v4::from_string("8.8.8.8");    
    asio::ip::tcp::endpoint ep;
    ep.address(ipa);

    asio::io_service io_service;
    asio::ip::tcp::resolver resolver(io_service);
    asio::ip::tcp::resolver::iterator destination = resolver.resolve(ep);

    std::cout << destination->host_name() << std::endl;

    return 0;
}

Answer 1

I haven’t used the resolver in Boost ASIO my self, but reading through the reference documentation it seems you shouldn’t be using ip::basic_resolver directly. Instead you should use e.g. ip::tcp::resolver in which case the endpoint is an instance of ip::tcp::endpoint.

Edit

As each host can have multiple host names, the OPs solution could be extended like this:

asio::ip::tcp::resolver::iterator itr = resolver.resolve(ep);
asio::ip::tcp::resolver::iterator end;

for (int i = 1; itr != end; itr++, i++)
    std::cout << "hostname #" << i << ": " << itr->host_name() << '\n';