| // Boost.Units - A C++ library for zero-overhead dimensional analysis and |
| // unit/quantity manipulation and conversion |
| // |
| // Copyright (C) 2003-2008 Matthias Christian Schabel |
| // Copyright (C) 2008 Steven Watanabe |
| // |
| // 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_UNITS_STATIC_CONSTANT_HPP |
| #define BOOST_UNITS_STATIC_CONSTANT_HPP |
| |
| #include <boost/units/config.hpp> |
| |
| /// A convenience macro that allows definition of static |
| /// constants in headers in an ODR-safe way. |
| #define BOOST_UNITS_STATIC_CONSTANT(name, type) \ |
| template<bool b> \ |
| struct name##_instance_t \ |
| { \ |
| static const type instance; \ |
| }; \ |
| \ |
| namespace \ |
| { \ |
| static const type& name = name##_instance_t<true>::instance; \ |
| } \ |
| \ |
| template<bool b> \ |
| const type name##_instance_t<b>::instance |
| |
| /// A convenience macro for static constants with auto |
| /// type deduction. |
| #if BOOST_UNITS_HAS_TYPEOF |
| |
| #if BOOST_UNITS_HAS_BOOST_TYPEOF |
| |
| #define BOOST_UNITS_AUTO_STATIC_CONSTANT(name, value) \ |
| BOOST_TYPEOF_NESTED_TYPEDEF(name##_nested_t, value) \ |
| BOOST_UNITS_STATIC_CONSTANT(name, name##_nested_t::type) = (value) |
| |
| #elif BOOST_UNITS_HAS_MWERKS_TYPEOF |
| |
| #define BOOST_UNITS_AUTO_STATIC_CONSTANT(name, value) \ |
| BOOST_UNITS_STATIC_CONSTANT(name, __typeof__(value)) = (value) |
| |
| #elif BOOST_UNITS_HAS_GNU_TYPEOF |
| |
| #define BOOST_UNITS_AUTO_STATIC_CONSTANT(name, value) \ |
| BOOST_UNITS_STATIC_CONSTANT(name, typeof(value)) = (value) |
| |
| #endif // BOOST_UNITS_HAS_BOOST_TYPEOF |
| |
| #endif // BOOST_UNITS_HAS_TYPEOF |
| |
| #endif // BOOST_UNITS_STATIC_CONSTANT_HPP |