Re: Expanding the use of FLEXIBLE_ARRAY_MEMBER for declarations like foo[1]

Michael Paquier <michael(dot)paquier(at)gmail(dot)com> writes:
> On Wed, Feb 18, 2015 at 10:09 PM, Andres Freund <andres(at)2ndquadrant(dot)com> wrote:
>> The compiler will complain if you use a FLEXIBLE_ARRAY_MEMBER in the
>> middle of a struct but not when when you embed a struct that uses it
>> into the middle another struct. At least gcc doesn't and I think it'd be
>> utterly broken if another compiler did that. If there's a compiler that
>> does so, we need to make it define FLEXIBLE_ARRAY_MEMBER to 1.

> clang does complain on my OSX laptop regarding that ;)

I'm a bit astonished that gcc doesn't consider this an error. Sure seems
like it should. (Has anyone tried it on recent gcc?) I am entirely
opposed to Andreas' claim that we ought to consider compilers that do warn
to be broken; if anything it's the other way around.

Moreover, if we have any code that is assuming such cases are okay, it
probably needs a second look. Isn't this situation effectively assuming
that a variable-length array is fixed-length?

regards, tom lane