[Boost-bugs] [Boost C++ Libraries] #11014: Inconsistent use of BOOST_PP_VARIADICS_MSVC

Subject: [Boost-bugs] [Boost C++ Libraries] #11014: Inconsistent use of BOOST_PP_VARIADICS_MSVC
From: Boost C++ Libraries (noreply_at_[hidden])
Date: 2015-02-10 23:12:45

#11014: Inconsistent use of BOOST_PP_VARIADICS_MSVC
-------------------------------------------+---------------------------
 Reporter:  Matthew Collett <m_collett@…>  |      Owner:  no-maintainer
     Type:  Bugs                           |     Status:  new
Milestone:  To Be Determined               |  Component:  preprocessor
  Version:  Boost 1.57.0                   |   Severity:  Cosmetic
 Keywords:                                 |
-------------------------------------------+---------------------------
 Clang generates multiple warnings of the form
 {{{
 'BOOST_PP_VARIADICS_MSVC' is not defined, evaluates to 0
 }}}

 In `config/config.hpp`, `BOOST_PP_VARIADICS_MSVC` is either set to 1 or
 left undefined, but the following files test the //value// of
 `BOOST_PP_VARIADICS_MSVC`, triggering the above warning when the macro is
 undefined:
 {{{
 seq/detail/binary_transform.hpp
 tuple/elem.hpp
 variadic/elem.hpp
 array/detail/get_data.hpp
 punctuation/is_begin_parens.hpp
 punctuation/detail/is_begin_parens.hpp
 facilities/is_empty_variadic.hpp
 facilities/detail/is_empty.hpp
 tuple/detail/is_single_return.hpp
 variadic/detail/is_single_return.hpp
 tuple/rem.hpp
 tuple/reverse.hpp
 tuple/size.hpp
 variadic/size.hpp
 list/to_array.hpp
 tuple/to_array.hpp
 variadic/to_array.hpp
 tuple/to_list.hpp
 tuple/to_seq.hpp
 test/tuple.cxx
 }}}
 Suggested fix: change all the above to use `#ifdef` or `defined` to test
 the //existence// of `BOOST_PP_VARIADICS_MSVC` instead of the value.  (A
 global replacement of `BOOST_PP_VARIADICS_MSVC` by
 `defined(BOOST_PP_VARIADICS_MSVC)` would be effective, if not elegant.)

 Alternate fix: change `config/config.hpp` so that
 `BOOST_PP_VARIADICS_MSVC` is either set to 1 or set to 0.
 In that case, the following files, which do currently test the existence
 of `BOOST_PP_VARIADICS_MSVC` (using `defined`), will need to be changed to
 test the value:
 {{{
 test/facilities.cxx
 test/isempty_variadic_standard_failure.cxx
 test/isempty_variadic_standard_failure2.cxx
 test/isempty.cxx
 }}}

-- 
Ticket URL: <https://svn.boost.org/trac/boost/ticket/11014>
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