On 4/3/2014 3:38 PM, Pierre Talbot wrote:
On 4/2/2014 3:48 PM, Pierre Talbot wrote:
Hi,
I defined a macro using Boost.Preprocessor that compiles and works fine under gcc but fails to compile under Clang. The macro is defined here: https://github.com/ptal/Boost.Expected/blob/master/include/boost/functional/...
As a quick shot, without actual testing, define BOOST_PP_VARIADICS to 1. It worked, thanks, but the problem is that it won't work if the user has
On 04/03/2014 05:31 PM, Edward Diener wrote: previously included preprocessor without having defined this macro.
Agreed for any given translation unit which includes any of your headers. I would just explain to end-users of your library using Boost 1.55 or lower that they need to define BOOST_PP_VARIADICS to 1 if they are using clang and Boost PP. And/or you could also add to your library ( in maybe a setup.hpp header ) something like: #if defined(BOOST_PP_VARIADICS) #if !BOOST_PP_VARIADICS #error BOOST_PP_VARIADICS cannot be defined as 0 when using Expected #endif #else #define BOOST_PP_VARIADICS 1 #endif
Maybe it should be defined by default if the language version is C++11?
In the latest modular-boost BOOST_PP_VARIADICS is defined as 1 for all versions of clang in the Boost PP config.hpp header. This was a conservative oversight regarding clang by Paul Mensonides when variadic macro support was added to pplib. I have since confirmed with clang developers that clang always supported variadic macros even in their earliest implementations and even without C++11 support.
And the error message follows this message, the file using the macro is https://github.com/ptal/Boost.Expected/blob/master/example/monadic_calculato...
Thanks for any helps, Pierre Talbot
Boost.Expected/example/monadic_calculator$ b2 ...patience... ...found 1246 targets... ...updating 2 targets... clang-linux.compile.c++.without-pth bin/clang-linux-3.5.0/debug/monadic_calculator.o monadic_calculator.cpp:141:15: error: use of undeclared identifier 'BOOST_PP_IIF_0' etokens = DO( ^ ../../include/boost/functional/do_yield.hpp:100:17: note: expanded from macro 'DO' #define DO(...) DO_SEQ(BOOST_PP_VARIADIC_TO_SEQ(__VA_ARGS__)) ^ ../../include/boost/functional/do_yield.hpp:97:3: note: expanded from macro 'DO_SEQ' BOOST_PP_SEQ_FOR_EACH_I(DO_ELEM, seq, seq) \ ^ /usr/local/boost_1_55_0/boost/preprocessor/seq/for_each_i.hpp:27:55: note: expanded from macro 'BOOST_PP_SEQ_FOR_EACH_I' # define BOOST_PP_SEQ_FOR_EACH_I(macro, data, seq) BOOST_PP_FOR((macro, data, seq (nil), 0), BOOST_PP_SEQ_FOR_EACH_I_P, BOOST_PP_SEQ_FOR_EACH_I_O, BOOST_PP_SEQ_FOR_EACH_I_M) ^ /usr/local/boost_1_55_0/boost/preprocessor/repetition/for.hpp:27:23: note: expanded from macro 'BOOST_PP_FOR' # define BOOST_PP_FOR BOOST_PP_CAT(BOOST_PP_FOR_, BOOST_PP_AUTO_REC(BOOST_PP_FOR_P, 256)) ^ /usr/local/boost_1_55_0/boost/preprocessor/cat.hpp:22:32: note: expanded from macro 'BOOST_PP_CAT' # define BOOST_PP_CAT(a, b) BOOST_PP_CAT_I(a, b) ^ /usr/local/boost_1_55_0/boost/preprocessor/cat.hpp:29:34: note: expanded from macro 'BOOST_PP_CAT_I' # define BOOST_PP_CAT_I(a, b) a ## b ^ <scratch space>:130:1: note: expanded from here BOOST_PP_FOR_1 ^ /usr/local/boost_1_55_0/boost/preprocessor/repetition/detail/for.hpp:22:37:
note: expanded from macro 'BOOST_PP_FOR_1' # define BOOST_PP_FOR_1(s, p, o, m) BOOST_PP_FOR_1_C(BOOST_PP_BOOL(p(2, s)), s, p, o, m) ^ /usr/local/boost_1_55_0/boost/preprocessor/repetition/detail/for.hpp:279:42:
note: expanded from macro 'BOOST_PP_FOR_1_C' # define BOOST_PP_FOR_1_C(c, s, p, o, m) BOOST_PP_IIF(c, m, BOOST_PP_TUPLE_EAT_2)(2, s) BOOST_PP_IIF(c, BOOST_PP_FOR_2, BOOST_PP_TUPLE_EAT_4)(BOOST_PP_EXPR_IIF(c, o)(2, s), p, o, m) ^ /usr/local/boost_1_55_0/boost/preprocessor/control/iif.hpp:18:37: note: expanded from macro 'BOOST_PP_IIF' # define BOOST_PP_IIF(bit, t, f) BOOST_PP_IIF_I(bit, t, f) ^ /usr/local/boost_1_55_0/boost/preprocessor/control/iif.hpp:25:39: note: expanded from macro 'BOOST_PP_IIF_I' # define BOOST_PP_IIF_I(bit, t, f) BOOST_PP_IIF_ ## bit(t, f) ^ <scratch space>:136:1: note: expanded from here BOOST_PP_IIF_0 ^