Repository navigation
[C++] Enable MSVC's new preprocessor to handle C++20 grammar such as __VA_OPT__ #50978
Description
Activity
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.
- changed the title
[-][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__`[/+]on 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?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?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.
- added a commit that references this issue
on Sep 8, 2026 - added a commit that references this issue
on Sep 21, 2026
Describe the enhancement requested
And we can try to remove the compile flag
/wd5105.Reference: #50252 (comment)
cc @raulcd
Component(s)
C++