Re: How to avoid warning with objc_msgSend

FROM : Finlay Dobbie
DATE : Tue Oct 05 18:15:36 2004

On 5 Oct 2004, at 09:46, Ryan Norton wrote:

>> Anyhow, assuming that GetNSView() is a function returning a pointer
>> to an NSViewInstance, why don't you just send it normally?
>>
>> id aView = GetNSView();
>> NSRect *rects;
>> int rectCount;
>> [aView getRectsBeingDrawn:&rects count:&rectCount];

>
> Because this generates both a runtime and compiler warning on 10.2 and
> lower (using the id instead of a plain GetNSView generates an extra
> compiler warning also) :).


Then do this:

id aView = GetNSView();
NSRect *rects = NULL;
int rectCount = 0;
if ([aView respondsToSelctor:@selector(getRectsBeingDrawn:count:)]) {
   [aView getRectsBeingDrawn:&rects count:&rectCount];
}

That obviously won't cause a runtime warning on 10.2 and lower. It'll
cause a compile-time warning, removing that would be an exercise for
the reader (hint: define a protocol, but this is really bad practice as
those methods aren't really implemented and thus the warning is
perfectly valid).

  -- Finlay