[cfe-dev] clang 'emulating' VC++ on Windows predefined macros

[Edward Diener via cfe-dev]

There is a build of clang which 'emulates' VC++ including the 
non-standard VC++ preprocessor. How can I tell, via preprocessor 
defines, when this occurs in preprocessor code ?

I am the author of Boost VMD and a maintainer of Boost PP and I need to 
set internal macros in both, when the non-standard VC++ preprocessor is 
being used, so that the VC++ workarounds which allow both libraries to 
work with VC++ are in effect.