43 lines
1.5 KiB
C++
43 lines
1.5 KiB
C++
// Copyright Daniel Wallin, David Abrahams 2005.
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// Distributed under the Boost Software License, Version 1.0.
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// (See accompanying file LICENSE_1_0.txt or copy at
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// http://www.boost.org/LICENSE_1_0.txt)
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#ifndef BOOST_PARAMETER_AUX_YESNO_HPP
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#define BOOST_PARAMETER_AUX_YESNO_HPP
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namespace boost { namespace parameter { namespace aux {
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// types used with the "sizeof trick" to capture the results of
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// overload resolution at compile-time.
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typedef char yes_tag;
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typedef char (&no_tag)[2];
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}}} // namespace boost::parameter::aux
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#include <boost/mpl/bool.hpp>
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namespace boost { namespace parameter { namespace aux {
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// mpl::true_ and mpl::false_ are not distinguishable by sizeof(),
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// so we pass them through these functions to get a type that is.
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::boost::parameter::aux::yes_tag to_yesno(::boost::mpl::true_);
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::boost::parameter::aux::no_tag to_yesno(::boost::mpl::false_);
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}}} // namespace boost::parameter::aux
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#include <boost/parameter/config.hpp>
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#if defined(BOOST_PARAMETER_CAN_USE_MP11)
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#include <boost/mp11/integral.hpp>
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namespace boost { namespace parameter { namespace aux {
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// mp11::mp_true and mp11::mp_false are not distinguishable by sizeof(),
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// so we pass them through these functions to get a type that is.
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::boost::parameter::aux::yes_tag to_yesno(::boost::mp11::mp_true);
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::boost::parameter::aux::no_tag to_yesno(::boost::mp11::mp_false);
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}}} // namespace boost::parameter::aux
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#endif // BOOST_PARAMETER_CAN_USE_MP11
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#endif // include guard
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