Re: clang++ 11 compilation issues

[Alexandre Duret-Lutz <adl@lrde.epita.fr>]

Florian Weimer <fweimer@redhat.com> writes:

> Would you be able to check whether __null is in the preprocessed
> sources?  If it is there (and the lack of further logged expansions
> suggests this), then this is a compiler bug.  __null is not zero, and
> should be fine to use as a null pointer constant.  This is why NULL is
> not defined as 0.

I can reproduce this without any preprocessing with clang 9, 10, and 11.

% cat foo.cc
int foo(char* msg_ctxt_id)
{
  return msg_ctxt_id == __null;
}
% clang++-11 -Wzero-as-null-pointer-constant -c foo.cc
foo.cc:3:25: warning: zero as null pointer constant [-Wzero-as-null-pointer-constant]
  return msg_ctxt_id == __null;
                        ^~~~~~
                        nullptr
1 warning generated.

% clang++-10 -Wzero-as-null-pointer-constant -c foo.cc
foo.cc:3:25: warning: zero as null pointer constant [-Wzero-as-null-pointer-constant]
  return msg_ctxt_id == __null;
                        ^~~~~~
                        nullptr
1 warning generated.
% clang++-9 -Wzero-as-null-pointer-constant -c foo.cc
foo.cc:3:25: warning: zero as null pointer constant [-Wzero-as-null-pointer-constant]
  return msg_ctxt_id == __null;
                        ^~~~~~
                        nullptr
1 warning generated.

-- 
Alexandre Duret-Lutz