On Thu, Apr 27, 2023 at 11:09:19AM +0200, Helmut Zeisel via Gcc wrote:
> I compiled GCC 13.1.0 with GCC 12 and had the environment variable CXXFLAGS
> set to -std=c++20
> This gives the error (both linux and cygin)
>
> gcc-13.1.0/libstdc++-v3/src/c++98/bitmap_allocator.cc:51:23: error: ISO C++17
> does not allow dynamic exception specifications
> 51 | _M_get(size_t __sz) throw(std::bad_alloc)
>
> After
>
> unset CXXFLAGS
>
> compilation works
Don't do it. libstdc++ carefully decides which parts of it should be
compiled by which C++ standard version. By forcing it to use
something it wasn't designed to work with you are breaking its assumptions.
Obviously c++98 code can use C++98 features...
Jakub
