text: //
  // resolver_query_base.hpp
  // ~~~~~~~~~~~~~~~~~~~~~~~
  //
  // Copyright (c) 2003-2010 Christopher M. Kohlhoff (chris at kohlhoff dot com)
  //
  // Distributed under the Boost Software License, Version 1.0. (See accompanying
  // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
  //
  
  #ifndef BOOST_ASIO_IP_RESOLVER_QUERY_BASE_HPP
  #define BOOST_ASIO_IP_RESOLVER_QUERY_BASE_HPP
  
  #if defined(_MSC_VER) && (_MSC_VER >= 1200)
  # pragma once
  #endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
  
  #include <boost/asio/detail/push_options.hpp>
  
  #include <boost/asio/detail/push_options.hpp>
  #include <boost/config.hpp>
  #include <boost/detail/workaround.hpp>
  #include <boost/asio/detail/pop_options.hpp>
  
  #include <boost/asio/detail/socket_types.hpp>
  
  namespace boost {
  namespace asio {
  namespace ip {
  
  /// The resolver_query_base class is used as a base for the
  /// basic_resolver_query class templates to provide a common place to define
  /// the flag constants.
  class resolver_query_base
  {
  public:
  #if defined(GENERATING_DOCUMENTATION)
    /// Determine the canonical name of the host specified in the query.
    static const int canonical_name = implementation_defined;
  
    /// Indicate that returned endpoint is intended for use as a locally bound
    /// socket endpoint.
    static const int passive = implementation_defined;
  
    /// Host name should be treated as a numeric string defining an IPv4 or IPv6
    /// address and no name resolution should be attempted.
    static const int numeric_host = implementation_defined;
  
    /// Service name should be treated as a numeric string defining a port number
    /// and no name resolution should be attempted.
    static const int numeric_service = implementation_defined;
  
    /// If the query protocol family is specified as IPv6, return IPv4-mapped
    /// IPv6 addresses on finding no IPv6 addresses.
    static const int v4_mapped = implementation_defined;
  
    /// If used with v4_mapped, return all matching IPv6 and IPv4 addresses.
    static const int all_matching = implementation_defined;
  
    /// Only return IPv4 addresses if a non-loopback IPv4 address is configured
    /// for the system. Only return IPv6 addresses if a non-loopback IPv6 address
    /// is configured for the system.
    static const int address_configured = implementation_defined;
  #else
    BOOST_STATIC_CONSTANT(int, canonical_name = AI_CANONNAME);
    BOOST_STATIC_CONSTANT(int, passive = AI_PASSIVE);
    BOOST_STATIC_CONSTANT(int, numeric_host = AI_NUMERICHOST);
  # if defined(AI_NUMERICSERV)
    BOOST_STATIC_CONSTANT(int, numeric_service = AI_NUMERICSERV);
  # else
    BOOST_STATIC_CONSTANT(int, numeric_service = 0);
  # endif
    // Note: QNX Neutrino 6.3 defines AI_V4MAPPED, AI_ALL and AI_ADDRCONFIG but
    // does not implement them. Therefore they are specifically excluded here.
  # if defined(AI_V4MAPPED) && !defined(__QNXNTO__)
    BOOST_STATIC_CONSTANT(int, v4_mapped = AI_V4MAPPED);
  # else
    BOOST_STATIC_CONSTANT(int, v4_mapped = 0);
  # endif
  # if defined(AI_ALL) && !defined(__QNXNTO__)
    BOOST_STATIC_CONSTANT(int, all_matching = AI_ALL);
  # else
    BOOST_STATIC_CONSTANT(int, all_matching = 0);
  # endif
  # if defined(AI_ADDRCONFIG) && !defined(__QNXNTO__)
    BOOST_STATIC_CONSTANT(int, address_configured = AI_ADDRCONFIG);
  # else
    BOOST_STATIC_CONSTANT(int, address_configured = 0);
  # endif
  #endif
  
  protected:
    /// Protected destructor to prevent deletion through this type.
    ~resolver_query_base()
    {
    }
  
  #if BOOST_WORKAROUND(__BORLANDC__, BOOST_TESTED_AT(0x564))
  private:
    // Workaround to enable the empty base optimisation with Borland C++.
    char dummy_;
  #endif
  };
  
  } // namespace ip
  } // namespace asio
  } // namespace boost
  
  #include <boost/asio/detail/pop_options.hpp>
  
  #endif // BOOST_ASIO_IP_RESOLVER_QUERY_BASE_HPP
  