1 # /* ************************************************************************** 2 # * * 3 # * (C) Copyright Edward Diener 2019. 4 # * Distributed under the Boost Software License, Version 1.0. (See 5 # * accompanying file LICENSE_1_0.txt or copy at 6 # * http://www.boost.org/LICENSE_1_0.txt) 7 # * * 8 # ************************************************************************** */ 9 # 10 # /* See http://www.boost.org for most recent version. */ 11 # 12 # ifndef BOOST_PREPROCESSOR_FACILITIES_VA_OPT_HPP 13 # define BOOST_PREPROCESSOR_FACILITIES_VA_OPT_HPP 14 # include <boost/preprocessor/variadic/has_opt.hpp> 15 # if BOOST_PP_VARIADIC_HAS_OPT() 16 # include <boost/preprocessor/control/iif.hpp> 17 # include <boost/preprocessor/facilities/check_empty.hpp> 18 # include <boost/preprocessor/tuple/rem.hpp> 19 # define BOOST_PP_VA_OPT_IMPL(atuple) \ 20 BOOST_PP_TUPLE_REM() atuple \ 21 /**/ 22 # define BOOST_PP_VA_OPT(rdata,rempty,...) \ 23 BOOST_PP_VA_OPT_IMPL \ 24 ( \ 25 BOOST_PP_IIF \ 26 ( \ 27 BOOST_PP_CHECK_EMPTY(__VA_ARGS__), \ 28 rempty, \ 29 rdata \ 30 ) \ 31 ) \ 32 /**/ 33 # endif /* BOOST_PP_VARIADIC_HAS_OPT() */ 34 # endif /* BOOST_PREPROCESSOR_FACILITIES_VA_OPT_HPP */ 35