On 23 September 2015 at 11:42, Tanu Kaskinen <tanuk at iki.fi> wrote:
> Hi all,
>
> We haven't been using anonymous structs and unions so far, because
> they've been non-standard in the past. C11 added support for them,
> however. GCC has supported them longer than that, I don't know about
> other compilers. Anonymous structs and unions are nice, and I think we
> should start allowing them. Any objections?
>
> In case the terms aren't clear, an anonymous struct looks like this:
>
> struct foo {
> struct {
> int a;
> int b;
> };
>
> int c;
> };
>
> struct foo f;
> f.a = 1;
> f.b = 2;
> f.c = 3;
>
> So struct foo contains another struct, but that struct doesn't have a
> name. Members of the inner struct are accessed as if they were members
> of the outer struct.
We spoke about why anonymous structures, and Tanu pointed out its use
in the memfd patches. I think it hampers, rather than helps,
readability.
> Anonymous unions look similar:
>
> struct foo {
> union {
> int i;
> float f;
> };
> };
>
> struct foo f;
> f.i = 1;
> f.f = 2.0;
Which is nice to have, indeed.
In general, I'm happy to move to C11, though.
People who are running non-Linux / non-gcc builds, time to speak up!
-- Arun
