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) 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_IS_DIMENSIONLESS_HPP
12 #define BOOST_UNITS_IS_DIMENSIONLESS_HPP
13 
14 ///
15 /// \file
16 /// \brief Check if a unit or quantity is dimensionless.
17 ///
18 
19 #include <boost/mpl/bool.hpp>
20 #include <boost/units/units_fwd.hpp>
21 
22 namespace boost {
23 
24 namespace units {
25 
26 template<class T>
27 struct is_dimensionless :
28     public mpl::false_
29 { };
30 
31 /// Check if a unit is dimensionless.
32 template<class System>
33 struct is_dimensionless< unit<dimensionless_type,System> > :
34     public mpl::true_
35 { };
36 
37 /// Check if a quantity is dimensionless.
38 template<class Unit,class Y>
39 struct is_dimensionless< quantity<Unit,Y> > :
40     public is_dimensionless<Unit>
41 { };
42 
43 } // namespace units
44 
45 } // namespace boost
46 
47 #endif // BOOST_UNITS_IS_DIMENSIONLESS_HPP
48