On 16 September 2015 at 10:16, Marc Glisse wrote: > On Wed, 16 Sep 2015, Jeffrey Walton wrote: > >> I'm trying to test for some C++ features via preprocessor macros. Some >> macros (like __GXX_VERSION__) are only triggered by including a C++ >> standard library file. According to Issue 67195, "cpp and g++ does not >> define __GLIBCXX__", I should only need to include c++config.h. >> >> The following is failing to pickup GCC's standard C++ configuration file: >> >> g++ -include c++config.h -dM -E - < /dev/.null | sort > > > Don't use this - < /dev/null, it only works halfway. Create a true empty > file empty.cc instead. > >> The command (and variations like "-include c\+\+config.h" and >> "-include bits/c++config.h") produces: > > > bits/c++config.h is the right one. As shown by looking in pretty much any libstdc++ header file: #include <bits/c++config.h> >> I guess a related question is, why is G++ using cc1, and not cc1plus? > > > Add -x c++ (gcc guesses based on the file name). Yes, it would make sense > for c++ to be the default with g++... https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67023
