Re: [Qemu-devel] [RFC v1 08/22] memory: provide defaults for MemoryListener operations

[Avi Kivity <avi@redhat.com>]

On 10/09/2012 05:14 PM, Anthony Liguori wrote:
>>> 
>>> I think it'd be nicer to check for NULL when invoking the functions in
>>> the memory core.
>>> 
>>> Then you avoid the exported stub functions entirely.
>>
>> Yes, that's the common style, but I happen not to like the extra check,
>> both from a performance point of view (doesn't apply here of course) and
>> from a readability point of view.
> 
> The trouble with your approach is that it introduced a subtle behavior
> based on ordering.   IOW:
> 
> MemoryListenerOps foo = {
>     MEMORY_LISTENER_DEFAULT_OPS,
>     .log_sync = ...,
> };
> 
> vs.
> 
> MemoryListenerOps foo = {
>     .log_sync = ...,
>     MEMORY_LISTENER_DEFAULT_OPS,
> };
> 
> Both compile fine but have potentially difficult to debug differences.
> Relying on zero-initialization eliminates the possibility of this problem.
> 

I don't think this is likely (esp. as the bad behaviour would be the
code not working at all) but i will update this for the next version.

-- 
error compiling committee.c: too many arguments to function