placeholders.hpp

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//
// placeholders.hpp
// ~~~~~~~~~~~~~~~~
//
// Copyright (c) 2003-2008 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 ASIO_PLACEHOLDERS_HPP
#define ASIO_PLACEHOLDERS_HPP

#if defined(_MSC_VER) && (_MSC_VER >= 1200)
# pragma once
#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)

#include "asio/detail/push_options.hpp"

#include "asio/detail/push_options.hpp"
#include <boost/bind/arg.hpp>
#include <boost/detail/workaround.hpp>
#include "asio/detail/pop_options.hpp"

namespace asio {
namespace placeholders {

#if defined(GENERATING_DOCUMENTATION)

unspecified error;

unspecified bytes_transferred;

unspecified iterator;

#elif defined(__BORLANDC__) || defined(__GNUC__)

inline boost::arg<1> error()
{
  return boost::arg<1>();
}

inline boost::arg<2> bytes_transferred()
{
  return boost::arg<2>();
}

inline boost::arg<2> iterator()
{
  return boost::arg<2>();
}

#else

namespace detail
{
  template <int Number>
  struct placeholder
  {
    static boost::arg<Number>& get()
    {
      static boost::arg<Number> result;
      return result;
    }
  };
}

#if BOOST_WORKAROUND(BOOST_MSVC, < 1400)

static boost::arg<1>& error
  = asio::placeholders::detail::placeholder<1>::get();
static boost::arg<2>& bytes_transferred
  = asio::placeholders::detail::placeholder<2>::get();
static boost::arg<2>& iterator
  = asio::placeholders::detail::placeholder<2>::get();

#else

namespace
{
  boost::arg<1>& error
    = asio::placeholders::detail::placeholder<1>::get();
  boost::arg<2>& bytes_transferred
    = asio::placeholders::detail::placeholder<2>::get();
  boost::arg<2>& iterator
    = asio::placeholders::detail::placeholder<2>::get();
} // namespace

#endif

#endif

} // namespace placeholders
} // namespace asio

#include "asio/detail/pop_options.hpp"

#endif // ASIO_PLACEHOLDERS_HPP