1// Boost.Units - A C++ library for zero-overhead dimensional analysis and
2// unit/quantity manipulation and conversion
3//
4// Copyright (C) 2003-2008 Matthias Christian Schabel
5// Copyright (C) 2007-2008 Steven Watanabe
6//
7// Distributed under the Boost Software License, Version 1.0. (See
8// accompanying file LICENSE_1_0.txt or copy at
9// http://www.boost.org/LICENSE_1_0.txt)
10
11#ifndef BOOST_UNITS_DIMENSIONLESS_TYPE_HPP
12#define BOOST_UNITS_DIMENSIONLESS_TYPE_HPP
13
14///
15/// \file
16/// \brief Dimension lists in which all exponents resolve to zero reduce to @c dimensionless_type.
17///
18
19#include <boost/mpl/long.hpp>
20#include <boost/mpl/deref.hpp>
21#include <boost/mpl/arithmetic.hpp>
22
23#include <boost/units/config.hpp>
24
25namespace boost {
26
27namespace units {
28
29namespace detail {
30
31struct dimension_list_tag;
32
33}
34
35/// Dimension lists in which all exponents resolve to zero reduce to @c dimensionless_type.
36struct dimensionless_type
37{
38 typedef dimensionless_type type;
39 typedef detail::dimension_list_tag tag;
40 typedef mpl::long_<0> size;
41};
42
43} // namespace units
44
45} // namespace boost
46
47#if BOOST_UNITS_HAS_BOOST_TYPEOF
48
49#include BOOST_TYPEOF_INCREMENT_REGISTRATION_GROUP()
50
51BOOST_TYPEOF_REGISTER_TYPE(boost::units::dimensionless_type)
52
53#endif
54
55#endif // BOOST_UNITS_DIMENSIONLESS_TYPE_HPP
56

source code of boost/boost/units/dimensionless_type.hpp