Martin Sebor <mse...@gmail.com> writes:
> @@ -1553,12 +1553,28 @@ struct line *thisline = (struct line *)
> thisline->length = this_length;
> @end smallexample
>
> -In ISO C90, you would have to give @code{contents} a length of 1, which
> -means either you waste space or complicate the argument to @code{malloc}.
> +Although the size of a zero-length array is zero, an array member of
> +this kind may increase the size the enclosing type as a result of tail
> +padding. The offset of a zero-length array member from the beginning
> +of the enclosing structure is the same as the offset of an array with
> +one or more elements of the same type. The alignment of a zero-length
> +array is the same as the alignment of its elements.
>
> -In ISO C99, you would use a @dfn{flexible array member}, which is
> -slightly different in syntax and semantics:
> +Declaring zero-length arrays in other contexts, including as interior
> +members of structure objects or as non-member objects is discouraged.
> +Accessing elements of zero-length arrays declared in such contexts is
> +undefined and may be diagnosed.
>
> +In the absence of the zero-length array extension, in ISO C90 the
> +@code{contents} array in the example above would typically be declared
> +to have a single element. Although this technique is discouraged, GCC
> +handles trailing one-element array members similarly to zero-length
> +arrays.
This last sentence seems a bit vague. E.g. GCC should never diagnose
an access to element 0 of a 1-element trailing array, whereas (like you
say above) it might for zero-length trailing arrays.
Thanks,
Richard
