Hi David
Sorry I think I was not understandable.
For example in Smalltalk I want to send the message
#initWithContentRectPointer:styleMask:backing:defer:
to a NSWindow
So in smalltalk I have something similar to:
nsWindowClass := Objc.ObjcRuntime at: 'NSWindow'.
nsWindow := nsWindowClass alloc.
nsWindow send: #initWithContentRectPointer:styleMask:backing:defer:
with: {nsRect. 15. Objc.ObjcAppKit nsBackingStoreBuffered. 1}.
The method #send:with: is just calling the function LKSendMessage.
In gnu-smalltalk the c-call-out mechanism transform the Smallinteger to the
C-integer (unsing right-shift...)
But LKSendMessage is unboxing each parameter before doing the ffi call to the
objc runtime:
for (i = 0; i < argc; i++)
{
const char *objCType = [sig getArgumentTypeAtIndex: i + 2];
UnboxValue(args[i], unboxedArgumentsBuffer[i + 2], objCType);
unboxedArguments[i + 2] = unboxedArgumentsBuffer[i + 2];
}
So the first parameter "args[i]" of the UnboxValue call is an plain c-integer
which is not what UnboxValue is expecting.
The call to [value unsignedIntValue] fail.
Let me know if I make it more clear.
Thanks
--Mathk
----- Message d'origine ----
> De : David Chisnall <[email protected]>
> À : Discussion list for Étoilé desktop environment <[email protected]>
> Envoyé le : Mer 13 avril 2011, 13h 41min 59s
> Objet : Re: [Etoile-discuss] Using LKSendMessage
>
> Hi Mathieu,
>
> On 13 Apr 2011, at 10:29, Mathieu Suen wrote:
>
> > I use LKSendMessage for writing the binding to gnu-smalltalk.
> > I had pick most of the implementation from the LanguageKit.
> > (I don't know if LanguageKit build on osx without gnustep)
>
> The interpreter can, the compiler can't (well, it should built, it just
> won't
>work).
>
> > But I cam across an issue when sending a message with integer parameter
>like:
> >
> > NSWindows class>>#initWithContentRectPointer:styleMask:backing:defer:
> >
> > LKSendMessage unbox does integer as follow:
> >
> >
> > case 'I':
> > *(unsigned int*)dest = [value unsignedIntValue];
> > break;
>
> Yup, this is extracting the unsigned integer representation (Objective-C
> type
>encoding 'I') from the object.
>
> >> From gnu-smalltalk I can't build the NSNumber because I need to send a
>message
>
> > like
> >
> > #numberWithInt: which should take a NSNumber as parameter...
>
> I'm not sure why you are building an NSNumber here at all. You just need
> the
>object to return an unsigned integer when sent an unsignedIntValue. The
>simplest way of doing this from Smalltalk code is likely to be right-shifting
>a
>SmallInt by one and then possibly zero-extending the result.
>
> NSNumber is a class that boxes C primitive integer values as objects, but in
>this case we are trying to unbox, not box, a value. The only time you'd need
>an NSNumber would be if one existed already and you passed it as a parameter
>to
>the method that expected an integer.
>
>
> > Any idea on how to solve this recursion?
>
> There shouldn't be any recursion here.
>
> David
>
> -- Sent from my STANTEC-ZEBRA
>
>
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