1 | // Copyright Daniel Wallin, David Abrahams 2005. |
2 | // Distributed under the Boost Software License, Version 1.0. |
3 | // (See accompanying file LICENSE_1_0.txt or copy at |
4 | // http://www.boost.org/LICENSE_1_0.txt) |
5 | |
6 | #ifndef BOOST_PARAMETER_AUX_YESNO_HPP |
7 | #define BOOST_PARAMETER_AUX_YESNO_HPP |
8 | |
9 | namespace boost { namespace parameter { namespace aux { |
10 | |
11 | // types used with the "sizeof trick" to capture the results of |
12 | // overload resolution at compile-time. |
13 | typedef char yes_tag; |
14 | typedef char (&no_tag)[2]; |
15 | }}} // namespace boost::parameter::aux |
16 | |
17 | #include <boost/mpl/bool.hpp> |
18 | |
19 | namespace boost { namespace parameter { namespace aux { |
20 | |
21 | // mpl::true_ and mpl::false_ are not distinguishable by sizeof(), |
22 | // so we pass them through these functions to get a type that is. |
23 | ::boost::parameter::aux::yes_tag to_yesno(::boost::mpl::true_); |
24 | ::boost::parameter::aux::no_tag to_yesno(::boost::mpl::false_); |
25 | }}} // namespace boost::parameter::aux |
26 | |
27 | #include <boost/parameter/config.hpp> |
28 | |
29 | #if defined(BOOST_PARAMETER_CAN_USE_MP11) |
30 | #include <boost/mp11/integral.hpp> |
31 | |
32 | namespace boost { namespace parameter { namespace aux { |
33 | |
34 | // mp11::mp_true and mp11::mp_false are not distinguishable by sizeof(), |
35 | // so we pass them through these functions to get a type that is. |
36 | ::boost::parameter::aux::yes_tag to_yesno(::boost::mp11::mp_true); |
37 | ::boost::parameter::aux::no_tag to_yesno(::boost::mp11::mp_false); |
38 | }}} // namespace boost::parameter::aux |
39 | |
40 | #endif // BOOST_PARAMETER_CAN_USE_MP11 |
41 | #endif // include guard |
42 | |
43 | |