(j3.2006) (SC22WG5.4779) [ukfortran] [WG5 letter ballot 4 on Fortran 2008 interpretations]

[Van Snyder]

N.M. Maclaren wrote:
> This is merely a remark on a response, not a response.
>
> On Sep 15 2012, Van Snyder wrote:
>>
>> -C-  ---  F08/0057   Interoperability with empty types
>>
>>          Does this need a compatibility caveat in 1.6?
>
> I doubt it.  While empty structures are allowed in C++, including in its
> C mode, and they are allowed as an extension in gcc and Intel C, it IS
> explicitly and clearly illegal in C and has not been added even to C11.
> Despite the statement in the question, it is neither a syntax error nor
> a constraint in C - it is merely forbidden, and so can be extended
> without needing a warning - but compatibility caveats for 
> interoperability
> with extended C languages does seem to be going a bit far.

Just because one declares a type with the BIND(C) attribute, and creates 
objects of that type, doesn't mean they are actually ever used for 
interoperation.  Bizarre, yes, but permitted by the standard -- until 
this interp.  Compatibility caveats in 1.6 are for compatibility with 
earlier Fortran standards, not for interoperability.  "We allowed this 
in Fortran 2003, but not any more."