On Sun, 24 Nov 2002, Jason Dufair wrote:

> Bert Freudenberg wrote:
> 
> >#( ...
> >   (header 'char' 282)
> >   ... ) 
> >  
> >
> Heh.  Talk about a case of RTFM.  Sorry I overlooked that. 

Actually it's more like RTFC.  I discovered this by looking in
ExternalStructure>>compileFields:withAccessors:. And I think giving the
size in bytes is misleading, it should be multiple of the base type's
size. That is, when I give it an (stuff 'int' 3) it should skip 
12 bytes. Andreas?

> If I have something declared in a C header as, for example, char**, can 
> FFI handle pointers to pointers?

Of course, but you have to dereference it yourself. See the hostname 
lookup snippet I sent, it doeas exactly this.

> I need to pass a file pointer in to a foreign function.  Is there some 
> way to get a file pointer in Smalltalk?

Not easily, that's hidden in the FilePlugin. You could open your files via
FFI, too. Or you might read the FilePlugin code and find a way to access
the actual file data.

> struct alloc_chain{
>   void *ptr;
>   struct alloc_chain *next;
> };
>
> fields
>     ^#(
>     ('ptr' 'void*')
>     ('next' 'AllocChain'))
> 
> sends Squeak out to lunch.  I've tried declaring 'next' as 'void*', but 
> I'm not sure if that will work.  Any ideas?

I think that should read ('next' AllocChain*) because it is a pointer. 

-- Bert