Re: [PATCH 2/2] PR libstdc++/86756 Move rest of std::filesystem to libstdc++.so

[Christophe Lyon <christophe dot lyon at linaro dot org>]

Hi Jonathan

On Sun, 6 Jan 2019 at 23:37, Jonathan Wakely <jwakely@redhat.com> wrote:
>
> Move std::filesystem directory iterators and operations from
> libstdc++fs.a to main libstdc++ library. These components have many
> dependencies on OS support, which is not available on all targets. Some
> additional autoconf checks and conditional compilation is needed to
> ensure the files will build for all targets. Previously this code was
> not compiled without --enable-libstdcxx-filesystem-ts but the C++17
> components should be available for all hosted builds.
>
> The tests for these components no longer need to link to libstdc++fs.a,
> but are not expected to pass on all targets. To avoid numerous failures
> on targets which are not expected to pass the tests (due to missing OS
> functionality) leave the dg-require-filesystem-ts directives in place
> for now. This will ensure the tests only run for builds where the
> filesystem-ts library is built, which presumably means some level of OS
> support is present.
>
>
> Tested x86_64-linux (old/new string ABIs, 32/64 bit), x86_64-w64-mingw32.
>
> Committed to trunk.
>

After this commit (r267616), I've noticed build failures for my
newlib-based toolchains:
aarch64-elf, arm-eabi:

In file included from
/tmp/5241593_7.tmpdir/aci-gcc-fsf/sources/gcc-fsf/gccsrc/libstdc++-v3/src/c++17/fs_ops.cc:57:
/tmp/5241593_7.tmpdir/aci-gcc-fsf/sources/gcc-fsf/gccsrc/libstdc++-v3/src/c++17/../filesystem/ops-common.h:142:11:
error: '::truncate' has not been declared
  142 |   using ::truncate;
      |           ^~~~~~~~
/tmp/5241593_7.tmpdir/aci-gcc-fsf/sources/gcc-fsf/gccsrc/libstdc++-v3/src/c++17/fs_ops.cc:
In function 'void std::filesystem::resize_file(const
std::filesystem::__cxx11::path&, uintmax_t, std::error_code&)':
/tmp/5241593_7.tmpdir/aci-gcc-fsf/sources/gcc-fsf/gccsrc/libstdc++-v3/src/c++17/fs_ops.cc:1274:19:
error: 'truncate' is not a member of 'posix'
 1274 |   else if (posix::truncate(p.c_str(), size))
      |                   ^~~~~~~~
make[5]: *** [fs_ops.lo] Error 1

I'm not sure if there's an obvious fix? Note that I'm using a rather
old newlib version, if that matters.

Thanks,

Christophe