On Thu, Sep 6, 2018 at 2:45 AM, John Selbie <jsel...@gmail.com> wrote: >> For Unixy builds, just don't specify -std. Only specify -std if you want > to ensure that builds will work with earlier standards, compilers, or > libraries, or for -std=c* without any special language or library features, > in which case you may also want to add -pedantic or more restrictive > options. > > Ahhhh…. that was my mistake. I had erroneously assumed that not specifying > -std would result in the oldest version of C++. A quick check: > > $ g++ foo.cpp -c -dM -E | grep cplus > #define __cplusplus 201402L > > I was compiling with C++ 14 the whole time. And it appears that when -std > is used, the GNU defines are taken out, which ultimately influence how > POSIX_VISIBLE Is defined within <features.h>.
By default GCC uses a -std=gnu++NN, not -std=c++NN. So you are getting mostly the latest C++ but it is GNU's flavor with non-standard things like Variable Length Arrays (VLA's). > I'm not sure if I agree that -std should hide the functions from unix > headers. (tldr: unix headers are explicitly outside the c++ standard, so > the moment they are included, you might as well assume the developer wants > it all...) Cygwin and Newlib conflate options in unexpected ways. I think they are making incorrect leaps about options. For example if you want Posix you may not want a GCC extension like VLA's. I doubt it will change, though. You just have to work around it. Jeff -- Problem reports: http://cygwin.com/problems.html FAQ: http://cygwin.com/faq/ Documentation: http://cygwin.com/docs.html Unsubscribe info: http://cygwin.com/ml/#unsubscribe-simple
