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Re: [C++ PATCH] warning about empty extern "C" structures

Daniel Jacobowitz <> writes:

| On Wed, May 17, 2006 at 06:15:25PM +0200, Gabriel Dos Reis wrote:
| > As has been pointed out; what you want is to warn for this construct
| > not just for C++, but also for GNU C.  I suggest you drop the "-c" in 
| > "empty-c-struct".
| For the record, if you meant my explanation, that's not at all what I
| was trying to point out.

OK, please explain it to me again.

>From my perspective

  extern "C" { struct S { }; }

is not turning the C++ compiler to define a C program.  So, the issue
here is whether it would cause a portability problem with C programs
-- this is a very rare case of C/c++ compatibility.  It also appears
that the definition of S is permitted in GNU C with completely a
different meaning.  Consequnently, the warning -- if we must have a
warning -- should not be confined to the C++ front-end...

Richard G. made a comment that I find quite appropriate.  If we are
going down this road, then we should start warning C codes.
Especially, sizeof ('a') and such.  The arguments for this patch hold
verbatim.  Hence, the question is what kind of consistency are we

I don't agree that it should be in -Wall though.

-- Gaby

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