Re: [Qemu-devel] Help debugging audio problem

[Markus Armbruster]

Programmingkid <address@hidden> writes:

> What does this code mean? 
>
>  if (!glue (s->nb_hw_voices_, TYPE)) {
>         return NULL;
>     }
>
> The code is found in audio_template.h at line 244. 
>
> I tried using GDB to figure out what it was doing, but had little luck. 
>
> The AC97 sound card does not work, and I'm trying to change that. 
>
> Any help would be great. Thanks.

Definition of macro glue is in osdep.h.  It glues together its
arguments.  Consult your textbook on C to understand how that kind of
arcane preprocessor magic works.

The audio subsystem is exceedingly fond of magic.

In actual use, macro TYPE has either value in or out, thus the result is
either s->nb_hw_voices_in or s->nb_hw_voices_out.