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

[Anthony Liguori]

Avi Kivity <address@hidden> writes:

> 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.

Thanks.  That's the only minor grip I had with the series.  It's really
a great cleanup!

Regards,

Anthony Liguori

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