Hi,
the structure is pretty simple :
// This is a STRUCT3
struct A {...}
struct B {
enum {E1,E2} kind // ok for mapping enum
union {
int64_t ref ; // there was a discussion about int64 platform independant
conversion. I just defined a Cint64_t as Clong
struct A *a;
} arg
}
As i explained, my problem is to differentiate int64_t from Cpointer Cstruct
in my vol2enum function..
Cheers
Le Lundi 20 Août 2012 18:18 CEST, David Matthews
<[email protected]> a écrit:
> On 20/08/2012 17:04, Gabriel Dos Reis wrote:
> > On Mon, Aug 20, 2012 at 10:27 AM, David Matthews
> > <[email protected]> wrote:
> >> On 20/08/2012 15:28, Pierre-Alain Bourdil wrote:
> >>>
> >>>
> >>> In ForeignTest, the vol2tree method use fromClong to differentiate
> >>> between NullTree, or Tree. My union, is made of 2 variants : a struct
> >>> pointer and a int64_t . I can't figure out how to decide if a given
> >>> vol is a pointer or an int64_t. is there a solution ? The inverse
> >>> conversion is pretty forward
> >>
> >>
> >> It's difficult to know what to do if you can't tell whether you have a
> >> number or the pointer to something. Are you actually returning these sort
> >> of values from your C code to ML? If not you can just use a dummy function
> >> that raises an exception in the conversion from a vol to the ML datatype.
> >>
> >> David
> >
> > I suspect Pierre-Alain is implicitly assuming that somehow PolyML uses
> > some form of low bits tag to differentiate whether an integer
> > bit-pattern (e.g. a
> > value of type intptr_t) is either a vol or an int64_t. I suspect the
> > answer is no.
>
> Perhaps it would help if we could see the definition of the union type in C.
>
> David
> _______________________________________________
> polyml mailing list
> [email protected]
> http://lists.inf.ed.ac.uk/mailman/listinfo/polyml
_______________________________________________
polyml mailing list
[email protected]
http://lists.inf.ed.ac.uk/mailman/listinfo/polyml
