Re: linking tool to use a framework : obj_send_msg error

[Thomas Kupper]

Hey David,

I already set -std=c99 in GNUmake.preamble. Tried both  
ADDITIONAL_CFLAGS and .._OBJCFLAGS but in both cases the __VA_LIST_  
macro isn't defined. Mmmh, I use gcc 4.3.
Do you have any other idea?

Thomas


On 13 Apr 2009, at 22:11, David Chisnall wrote:

> On 13 Apr 2009, at 20:49, Thomas Kupper wrote:
>
> > > There is probably some 'optimisation' in the framework calling the  
> > > Apple runtime message send function directly (the quotes because  
> > > anything doing I/O like this is likely to gain an imperceptible  
> > > performance increase from calling the runtime functions directly  
> > > rather than using -methodForSelector:). Try grepping the source  
> > > code for objc_msgSend() and, in files that contain it, add this  
> > > macro:
> > >
> > > #define objc_msgSend(theReceiver, theSelector, ...) \
> > > objc_msg_lookup(theReceiver, theSelector)(theReceiver,  
> > > theSelector, ## __VA_LIST__)
> >
> >
> > Perfect! That's exactly what causes the error. In one file there  
> > are three calls to objc_msgSend. Now I tried to define the macro  
> > you mentioned. Unfortunately the # __VA_LIST__ part is not  
> > recognized and Google wasn't any help, and neither was a find ... - 
> > exec fgrep ....
>
> Sounds like you have your compiler set to use some archaic dialect  
> of C.  Add -std=c99 to your CFLAGS.
>
> > On the other hand, if there are only three calls to objc_msgSend in  
> > only one file I could maybe just replace these three calls. But the  
> > objc_msg_lookup calls seems to be quite unusal.
>
> You can do that too, just expand the macro, so:
>
> objc_msgSend(obj, sel, args);
>
> becomes:
>
> objc_msg_lookup(obj, sel)(obj, sel, args);
>
> (objc_msg_lookup() returns a pointer to the function that you call.   
> objc_msgSend() does the lookup and the call as a single operation in  
> the Mac runtime).
>
> David