Re: [PATCH 2/2] Add warn_unused_result attr to AUD_register_card

[Manos Pitsidianakis]

On Fri, 10 Nov 2023 13:20, "Daniel P. Berrangé" <berrange@redhat.com> wrote:
> Your approach to the problem:
>
>  if (!AUD_register_card("OMAP EAC", &s->codec.card, &error_fatal)) {
>    exit(1);
>  }
>
> is adding dead-code because the exit(1) will never be reachable. So while
> it lets you squelch the unused result warning, it is verbose and misleading
> to anyone who sees it.
>
> Perhaps a more viable option is to pull in gnulib's ignore_value macro
>
>  #define ignore_value(x) \
>    (__extension__ ({ __typeof__ (x) __x = (x); (void) __x; }))
>
> and then we would have just this:
>
> ignore_value(AUD_register_card("OMAP EAC", &s->codec.card, &error_fatal));

Good suggestion, thanks!

And to be fair, I did put a comment directly above that line to explain 
the unreachable code path. :)

+    /*
+     * We pass error_fatal so on error QEMU will exit(). But we check 
the
+     * return value to make the warn_unused_result compiler warning go 
away.
+     */