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[C++] Enable MSVC's new preprocessor to handle C++20 grammar such as __VA_OPT__ #50978
Description
Describe the enhancement requested
And we can try to remove the compile flag /wd5105.
Reference: #50252 (comment)
cc @raulcd
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HuaHuaY commentedon Aug 25, 2026
I found that we can't do this because boost 1.88 can't be compiled with
/Zc:preprocessor. Reference: boostorg/multiprecision#677, boostorg/multiprecision#667.We can fix this issue after we upgrade boost to 1.89.
[-][C++] Enable MSVC's new preprocesser to handle C++20 grammar such as `__VA_OPT__`[/-][+][C++] Enable MSVC's new preprocessor to handle C++20 grammar such as `__VA_OPT__`[/+]kou commentedon Aug 25, 2026
How about specifying
/Zc:preprocessorglobally and specifying/Zc:preprocessor-(trailing-is important to disable this feature) only for compilation units that useboost/multiprecionwhenBoost_VERSIONis less than 1.89?HuaHuaY commentedon Aug 26, 2026
I can accept this approach. I will leave a TODO reminder that the latter flag can be fixed after upgrading to Boost 1.89. I will update the PR soon.
GH-51116: [C++] Update bundled Boost (#51132)
GH-50978: [C++] Enable MSVC's new preprocessor to handle C++20 grammar (
kou commentedon Sep 21, 2026
Issue resolved by pull request 50979
#50979