Hi Stephan,

Thanks for replying from your hotel,

On Wed, Jan 09, 2002 at 11:47:59PM +0100, Stephan Rudlof wrote:
> Somewhat late, since I'm sitting in a hotel (working outside and had big
> problems to connect...), but here are a few hints:
> 
> Joshua 'Schwa' Gargus wrote:
> > 
> > Hello,
> > 
> > I'm having trouble passing around a pointer between interpreted Squeak
> > code and compiled plugin code.  I have a primitive method that returns
> > a pointer like this:
> > 
> > ^ aPtr asOop: Unsigned
> > 
> > This seems to work fine; depending on the value, I get either a
> > SmallInteger or a LargePositiveInteger.  The problem arises when I try
> > to pass this into another primitive method that looks like this:
> > 
> 
> > primNeedPointer: aPtr
> > 
> >     self
> >         primitive: 'primNeedPointer'
> >         parameters: #(Unsigned)
> >     "more stuff..."
> > 
> > The generated C code causing the failure is:
> > 
> > interpreterProxy->success(interpreterProxy->isKindOf(interpreterProxy->stackValue(0), "Unsigned"));
> > 
> > Looking at the code for isKindOf(), it is clear why it fails: the
> > object (a SmallInteger or LargePositiveInteger) is not an instance
> > of Unsigned or one of its subclasses.
> 
> You could use "Integer" here.
> 
> But there is another problem: if you have a LargeInteger as 'ptr' its oop
> may have changed between the calls of the two prims.

I suppose that this is because of a possible garbage collection.  However, I'm 
failing to see why this is a problem, since the value of the LargeInteger would
be the same even if its oop changed.  Could you clarify exactly what the problem
is?

Thanks again,
Joshua

> 
> Greetings,
> 
> Stephan
> 
> > 
> > I followed the directions on:
> > http://minnow.cc.gatech.edu/squeak/850
> > as closely as possible.  What am I doing wrong?
> > 
> > Thanks,
> > Joshua
> 
> -- 
> Stephan Rudlof (sr at evolgo.de)
>    "Genius doesn't work on an assembly line basis.
>     You can't simply say, 'Today I will be brilliant.'"
>     -- Kirk, "The Ultimate Computer", stardate 4731.3
>