comparison DEPENDENCIES/generic/include/boost/preprocessor/tuple/elem.hpp @ 101:c530137014c0

Update Boost headers (1.58.0)

 #  * accompanying file LICENSE_1_0.txt or copy at
 #  * http://www.boost.org/LICENSE_1_0.txt)
 #  */
 #
 # /* Revised by Paul Mensonides (2002-2011) */
-# /* Revised by Edward Diener (2011) */
+# /* Revised by Edward Diener (2011,2014) */
 #
 # /* See http://www.boost.org for most recent version. */
 #
 # ifndef BOOST_PREPROCESSOR_TUPLE_ELEM_HPP
 # define BOOST_PREPROCESSOR_TUPLE_ELEM_HPP
 #
 # include <boost/preprocessor/cat.hpp>
 # include <boost/preprocessor/config/config.hpp>
+# include <boost/preprocessor/facilities/expand.hpp>
 # include <boost/preprocessor/facilities/overload.hpp>
 # include <boost/preprocessor/tuple/rem.hpp>
 # include <boost/preprocessor/variadic/elem.hpp>
+# include <boost/preprocessor/tuple/detail/is_single_return.hpp>
 #
 # if BOOST_PP_VARIADICS
 #    if BOOST_PP_VARIADICS_MSVC
 #        define BOOST_PP_TUPLE_ELEM(...) BOOST_PP_TUPLE_ELEM_I(BOOST_PP_OVERLOAD(BOOST_PP_TUPLE_ELEM_O_, __VA_ARGS__), (__VA_ARGS__))
 #        define BOOST_PP_TUPLE_ELEM_I(m, args) BOOST_PP_TUPLE_ELEM_II(m, args)
 #        define BOOST_PP_TUPLE_ELEM_II(m, args) BOOST_PP_CAT(m ## args,)
+/*
+  Use BOOST_PP_REM_CAT if it is a single element tuple ( which might be empty )
+  else use BOOST_PP_REM. This fixes a VC++ problem with an empty tuple and BOOST_PP_TUPLE_ELEM
+  functionality. See tuple_elem_bug_test.cxx.
+*/
+#    	 define BOOST_PP_TUPLE_ELEM_O_2(n, tuple) \
+			BOOST_PP_VARIADIC_ELEM(n, BOOST_PP_EXPAND(BOOST_PP_TUPLE_IS_SINGLE_RETURN(BOOST_PP_REM_CAT,BOOST_PP_REM,tuple) tuple)) \
+			/**/
 #    else
 #        define BOOST_PP_TUPLE_ELEM(...) BOOST_PP_OVERLOAD(BOOST_PP_TUPLE_ELEM_O_, __VA_ARGS__)(__VA_ARGS__)
+#    	 define BOOST_PP_TUPLE_ELEM_O_2(n, tuple) BOOST_PP_VARIADIC_ELEM(n, BOOST_PP_REM tuple)
 #    endif
-#    define BOOST_PP_TUPLE_ELEM_O_2(n, tuple) BOOST_PP_VARIADIC_ELEM(n, BOOST_PP_REM tuple)
 #    define BOOST_PP_TUPLE_ELEM_O_3(size, n, tuple) BOOST_PP_TUPLE_ELEM_O_2(n, tuple)
 # else
 #    if BOOST_PP_CONFIG_FLAGS() & BOOST_PP_CONFIG_MSVC()
 #        define BOOST_PP_TUPLE_ELEM(size, n, tuple) BOOST_PP_TUPLE_ELEM_I(BOOST_PP_CAT(BOOST_PP_TUPLE_ELEM_, n), BOOST_PP_CAT(BOOST_PP_CAT(BOOST_PP_TUPLE_ELEM_E_, size), tuple))
 #        define BOOST_PP_TUPLE_ELEM_I(m, args) BOOST_PP_TUPLE_ELEM_II(m, args)