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BOOST_PP_VARIADICS_MSVC set incorrectly for EDG in Microsoft emulation mode

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Assessment

Difficulty
2/5
Estimated time
1-3 hours
Newbie friendliness
45/100
Issue type
Bug
Clarity
Clearly specified
Activity status
Stale
Tech stack
cpp
Domain
compilers

Research direction

Start in preprocessor/config/config.hpp and inspect the condition that sets BOOST_PP_VARIADICS_MSVC, focusing on the interaction between _MSC_VER, EDG, and _MSVC_TRADITIONAL. The issue is done when EDG in Microsoft emulation mode no longer incorrectly sets BOOST_PP_VARIADICS_MSVC to 0; no specific test file is mentioned.

Written by the indexing model from the issue text.

Description

In preprocessor/config/config.hpp, the condition for setting BOOST_PP_VARIADICS_MSVC to 1 is:

# if defined _MSC_VER && _MSC_VER >= 1400 && !defined(__clang__) && (defined(__INTELLISENSE__) || (defined(__INTEL_COMPILER) && __INTEL_COMPILER >= 1700) || !(defined __EDG__ || defined __GCCXML__ || (defined __NVCC__ && defined __CUDACC__) || defined __PATHSCALE__ || defined __DMC__ || defined __CODEGEARC__ || defined __BORLANDC__ || defined __MWERKS__ || defined __SUNPRO_CC || defined __HP_aCC || defined __MRC__ || defined __SC__ || defined __IBMCPP__ || defined __PGI)) && (!defined(_MSVC_TRADITIONAL) || _MSVC_TRADITIONAL)
Unless modified by a customer, when the EDG front end is invoked in Microsoft emulation mode, it defines both _MSC_VER and EDG, with the value of MSVC_TRADITIONAL being set depending on the --[no]_ms_std_preprocessor command-line option. When the EDG front end is invoked emulating the traditional Microsoft preprocessor (currently the default in Microsoft emulation mode), this results in defining BOOST_PP_VARIADICS_MSVC to 0, causing errors when Boost preprocessor variadics are used.

Presumably the fix is simply to remove the "defined EDG" test in this conditional.

Dominant language
C++
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