Comment # 6 on bug 1221682 from David Disseldorp

(In reply to Michal Jireš from comment #5)
> > I wonder whether the sasl_callback_t.proc entry could get away with an unnamed 
> > union covering all argument cases for a valid @id?
> 
> Quickly looking at cyrus-sasl's saslplug.h, *unnamed* union would not be
> enough:
>  36 typedef int (*sasl_callback_ft)(void);
>  37 typedef int sasl_getcallback_t(sasl_conn_t *conn,
>  38              unsigned long callbackid,
>  39              sasl_callback_ft * pproc,
>  40              void **pcontext);
> 
> 
> > As mentioned in comment#1 , I think the cyrus-sasl callback interface
> > deserves to be tracked as a separate bug. @Michal: if you agree, could you
> > raise a ticket?
> > I think this can be closed once cyrus-sasl is tracked elsewhere.
> 
> I don't see a problem with the sasl_callback_t interface (at least not more
> than with void* ).
> Maybe using:
> void (*proc)(void);
> could be slightly preferable. At least it suppresses warnings and makes it a
> bit clearer that it is a generic function pointer.

The callback API types have a different number of arguments passed. As-is it
would appear that it's easy to have a mismatch between caller and callee
function parameters... Couldn't that lead callback functions to access
caller-uninitialized registers, if the caller passed fewer parameters than
expected?

Anyhow, I'm also okay with leaving it as is if that's your preference. This can
be closed once https://build.opensuse.org/request/show/1160083 is merged.