What does zero-length array mean at file scope?

[Andrew Haley]

Joseph S. Myers wrote:
> On Sun, 24 May 2009, Andrew Haley wrote:
> 
>> Of course we have to fix the assembler output.  For [any] two declarations
>> a and b, &a != &b, even when a is a zero-length array.  So, you have to
>> allocate at least one byte.
> 
> I don't think this is necessarily part of the semantics for the GNU 
> extensions of zero-length arrays and empty structures.  Certainly when 
> they are used in the middle of a structure they are not expected to take 
> up any space (so their address may be the same as that of the next 
> member).

I see.  In that this breaks the semantics of C in a pretty fundamental
way this is pretty bad, but it's been in gcc for a long time.

Andrew.