Re: [Chicken-users] FFI and references

[felix winkelmann]

Yes, because the reference is an argument, and not a result in
this case.


cheers,
felix


On Mon, 3 Jan 2005 15:47:46 +0000, Joel Reymont <address@hidden> wrote:
> > felix winkelmann wrote:
> 
> >This is likely to break. getPixel returns a color instance,
> >but the result-value unmarshalling will take it's address and return a
> >pointer,
> >which (AFAIK) would on return from the wrapper procedure be deallocated.
> >Does getPixel return a true instance or a reference? Actually the
> >C++ compiler should complain in both cases.
> 
> The following works just fine provided that you pass (slot-ref 'this
> color) into print-color:
> 
> (declare (unit foo))
> (declare (uses tinyclos)
>          (uses color))
> 
> #>
> #include "color.hpp"
> 
> extern void print_color(const color& c);
> 
> <#
> 
> (define-foreign-type color (ref "color"))
> 
> (define print-color (foreign-lambda void "print_color"
>                                     color))
> 
>     Joel
> 
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