Re: [V1][PATCH 1/3] Provide element_count attribute to flexible array member field (PR108896)

[Qing Zhao <qing.zhao@oracle.com>]

> On May 25, 2023, at 5:02 PM, Joseph Myers <joseph@codesourcery.com> wrote:
> 
> What happens if the field giving the number of elements is in a contained 
> anonymous structure or union?
> 
> struct s {
>  struct { size_t count; };
>  int array[] __attribute__ ((element_count ("count")));
> };
> 
> This ought to work - a general principle in C is that anonymous structures 
> and unions are transparent as far as name lookup for fields is concerned.  
> But I don't see any testcases for it and I'm not sure it would work with 
> the present code.
Will check on this and add testing case for this case.
> 
> What if the string is a wide string?  I don't expect that to work (either 
> as a matter of interface design, or in the present code), but I think that 
> case should have a specific check and error.

Dump question: how to check whether the string is a wide string? -:)

> 
> What happens in the case where -fexec-charset specifies a 
> non-ASCII-compatible character set?  I expect that to work OK with the 
> existing code, because translation of string literals to the execution 
> character set is disabled in __attribute__ parsing, but having a testcase 
> for it would be good.
Okay, will check on this and add test case.
> 
> What happens if the field referenced for the element count does not have 
> integer type?  I'd expect an error, but don't see one in the code or tests 
> here.
Yes, that’s right, will add this.

Thanks a lot.

Qing

> 
> -- 
> Joseph S. Myers
> joseph@codesourcery.com