Re: [boost] Where we are 1.65.0

Subject: Re: [boost] Where we are 1.65.0
From: Stephan T. Lavavej (stl_at_[hidden])
Date: 2017-08-09 20:23:00

[John Maddock]
> I wonder if we should have a blanket check for C++17 in suffix.hpp which would
> then set these macros regardless of compiler if it claims to be in 
> C++17 mode?  That won't help with VC++ which hasn't updated __cplusplus
> in a while, but would have avoided the clang issue...

_MSVC_LANG indicates whether /std:c++14, /std:c++17, or /std:c++latest is being used. You can test it like this:

#ifndef YOUR_CXX17_MACRO
 #ifdef _MSVC_LANG
  #if _MSVC_LANG > 201402
   #define YOUR_CXX17_MACRO 1
  #else
   #define YOUR_CXX17_MACRO 0
  #endif
 #else
  #if __cplusplus > 201402
   #define YOUR_CXX17_MACRO 1
  #else
   #define YOUR_CXX17_MACRO 0
  #endif
 #endif
#endif

Alternatively, instead of asking the compiler, you can ask our STL whether it's in C++17 mode. Simply include any header (good old <ciso646> will do) and _HAS_CXX17 will be defined to either 0 or 1.

Thanks,
STL