freeHaskellFunctionPtr
Manuel M. T. Chakravarty
chak at cse.unsw.edu.au
Tue Jan 2 20:27:20 EST 2001
Fergus Henderson <fjh at cs.mu.oz.au> wrote,
> On 02-Jan-2001, Marcin 'Qrczak' Kowalczyk <mk167280 at zodiac.mimuw.edu.pl> wrote:
> >
> > and even the ability to cast between data pointers and function pointers
> > is described as a common non-standard extension in ISO/ANSI C99.
>
> That's true. ANSI/ISO C does not guarantee that a data pointer will
> fit in a function pointer or vice versa.
>
> If you want something that could be either a data pointer or
> a function pointer, you need to use a union:
>
> union {
> void *data;
> void (*func)(void);
> }
This means that we should not provide
castFunPtrToPtr :: FunPtr a -> Ptr b
castPtrToFunPtr :: Ptr a -> FunPtr b
Has anybody ever used these casts? As long as `FunPtr' is
used for f.e.d., I don't see much use in these casts. It
certainly doesn't make much sense to peek and poke an
address produced by f.e.d.
So, I propose to drop these two casts. Objections?
Cheers,
Manuel
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