Re: [Emacs-diffs] master b7fa6b1 1/4: Simplify use of FOR_EACH_TAIL

["Johan Bockgård" <bojohan@gnu.org>]

Paul Eggert <eggert@cs.ucla.edu> writes:

> Portable C99 code cannot declare two or more identifiers in the same
> for-loop, due to an ambiguity in the C99 standard, which says (6.8.5
> para 3) "The declaration part of a for statement shall only declare
> identifiers for objects having storage class auto or register." This
> constraint can be interpreted as meaning (A) when a for-statement
> declares an object's name, the name must have storage class auto or
> register, or (B) all identifiers declared by a for-statement must name
> objects with storage class auto or register. Although I suspect (A)
> was intended and that's what GCC does, (B) is also a plausible
> interpretation and that's what Clang does. Interpretation (B)
> disallows anonymous structs here, as such structs declare member
> names.

    "The intent is clear enough; [...] identifiers which do not denote
    objects with auto or register storage classes, [...] are not allowed
    in this context."

http://www.open-std.org/jtc1/sc22/wg14/www/docs/dr_277.htm