Re: Ptr and ForeignPtr Questions

At 2001-10-10 01:19, I wrote: >foreign import "foo" raw_foo :: Ptr () -> IO (Ptr ()); > >foo :: Ptr SomeLinkedList -> IO (ConstPtr Char); >foo = importFunction raw_foo; Actually I don't need to convert the pointers, do I? If I have (Storable SomeLinkedList), I can just declare

Re: Ptr and ForeignPtr Questions

At 2001-09-23 23:54, I wrote: >As you point out, there are restrictions >on just what existing C functions you can bind to. If your function looks >like this: > > const char* foo (struct SomeLinkedList*); > >...you have no choice but to write 'impedance-matching' code for that >function.

Re: Ptr and ForeignPtr Questions

At 2001-09-23 23:12, Manuel M. T. Chakravarty wrote: >> I was just hoping for GHC to be able to spit out headers for 'foreign >> import' functions that the user could then define. This merely means a >> map from some restricted set of Haskell function types to C types. > >Functionality like tha

Re: Ptr and ForeignPtr Questions

Ashley Yakeley <[EMAIL PROTECTED]> wrote, > At 2001-09-23 19:14, Manuel M. T. Chakravarty wrote: > > >Hmm, we must be misunderstanding each other. Given that you > >have > > > > foreign import strcat :: Ptr CChar -> Ptr CChar -> IO (Ptr CChar) > > > >How do you want to know whether the C proto

Re: Ptr and ForeignPtr Questions

At 2001-09-23 19:14, Manuel M. T. Chakravarty wrote: >Hmm, we must be misunderstanding each other. Given that you >have > > foreign import strcat :: Ptr CChar -> Ptr CChar -> IO (Ptr CChar) > >How do you want to know whether the C prototype is > > char *strcat(char *dest, const char *src)

Re: Ptr and ForeignPtr Questions

Ashley Yakeley <[EMAIL PROTECTED]> wrote, > At 2001-09-23 04:04, Marcin 'Qrczak' Kowalczyk wrote: > > >It would be impossible then to directly call a C function with a > >parameter declared as a const pointer. It's illegal in C to have > >mismatching prototypes of the same function. > > You can

Re: Ptr and ForeignPtr Questions

Ashley Yakeley <[EMAIL PROTECTED]> wrote, > At 2001-09-23 04:02, Manuel M. T. Chakravarty wrote: > > >> I would assume that Ptr types would always be mapped to non-const > >> pointers. Do you have an example of a Haskell type for a foreign import > >> function, for which the corresponding C fu

Re: Ptr and ForeignPtr Questions

At 2001-09-23 15:56, Marcin 'Qrczak' Kowalczyk wrote: >> But do you have an example of a Haskell type for a foreign import >> function, for which the corresponding C function type would be ambiguous? > >Ptr CChar (as an argument). It could be either char * or const char *. It's always char*. A

Re: Ptr and ForeignPtr Questions

At 2001-09-23 04:04, Marcin 'Qrczak' Kowalczyk wrote: >It would be impossible then to directly call a C function with a >parameter declared as a const pointer. It's illegal in C to have >mismatching prototypes of the same function. You can always do this: module MyModule where { f

Re: Ptr and ForeignPtr Questions

Sun, 23 Sep 2001 15:41:41 -0700, Ashley Yakeley <[EMAIL PROTECTED]> pisze: > But do you have an example of a Haskell type for a foreign import > function, for which the corresponding C function type would be ambiguous? Ptr CChar (as an argument). It could be either char * or const char *. --

Re: Ptr and ForeignPtr Questions

At 2001-09-23 04:02, Manuel M. T. Chakravarty wrote: >> I would assume that Ptr types would always be mapped to non-const >> pointers. Do you have an example of a Haskell type for a foreign import >> function, for which the corresponding C function type would be ambiguous? > >Take, for example,

Re: Ptr and ForeignPtr Questions

Sun, 23 Sep 2001 02:04:49 -0700, Ashley Yakeley <[EMAIL PROTECTED]> pisze: > I would assume that Ptr types would always be mapped to non-const > pointers. It would be impossible then to directly call a C function with a parameter declared as a const pointer. It's illegal in C to have mismatchin

Re: Ptr and ForeignPtr Questions

Ashley Yakeley <[EMAIL PROTECTED]> wrote, > At 2001-09-23 00:45, Manuel M. T. Chakravarty wrote: > > >No, unfortunately not. Consider, for example, that storage > >qualifiers would have to be generated correctly and there is > >no way to determine form a Haskell type whether a `const' > >modifi

Re: Ptr and ForeignPtr Questions

At 2001-09-23 00:45, Manuel M. T. Chakravarty wrote: >No, unfortunately not. Consider, for example, that storage >qualifiers would have to be generated correctly and there is >no way to determine form a Haskell type whether a `const' >modifier needs to be added. I would assume that Ptr types wo

Re: Ptr and ForeignPtr Questions

Ashley Yakeley <[EMAIL PROTECTED]> wrote, > At 2001-09-21 02:20, Manuel M. T. Chakravarty wrote: > > >One could attempt to generate C prototypes from the Haskell > >type declarations or similar things, btu it doesn't work > >out. > > Why not? Isn't there a straightforward type map? No, unfortu

Re: Ptr and ForeignPtr Questions

At 2001-09-21 02:20, Manuel M. T. Chakravarty wrote: >One could attempt to generate C prototypes from the Haskell >type declarations or similar things, btu it doesn't work >out. Why not? Isn't there a straightforward type map? -- Ashley Yakeley, Seattle WA __

Re: Ptr and ForeignPtr Questions

Ashley Yakeley <[EMAIL PROTECTED]> wrote, > At 2001-09-21 01:39, Manuel M. T. Chakravarty wrote: > > >That's ok. All I am saying is that the FFI doesn't ensure > >any concistency between the Haskell and the C type. > > Well it can't can it? There's no type information in object-code symbols >

Re: Ptr and ForeignPtr Questions

At 2001-09-21 01:39, Manuel M. T. Chakravarty wrote: >That's ok. All I am saying is that the FFI doesn't ensure >any concistency between the Haskell and the C type. Well it can't can it? There's no type information in object-code symbols (unless you use C++ identifier mangling, which Haskell d

Re: Ptr and ForeignPtr Questions

Ashley Yakeley <[EMAIL PROTECTED]> wrote, > At 2001-09-20 19:32, Manuel M. T. Chakravarty wrote: > > >What I meant with the remark that you quote is that if you > >would use > > > > foreign import foo :: Ptr Int -> IO Float > > > >with > > > > float foo (float *x) > > { > >return *x; > >

Re: Ptr and ForeignPtr Questions

At 2001-09-20 19:32, Manuel M. T. Chakravarty wrote: >What I meant with the remark that you quote is that if you >would use > > foreign import foo :: Ptr Int -> IO Float > >with > > float foo (float *x) > { >return *x; > } > >the system will not complain, but your program may dump >core.

Re: Ptr and ForeignPtr Questions

Ashley Yakeley <[EMAIL PROTECTED]> wrote, > At 2001-09-20 06:55, Manuel M. T. Chakravarty wrote: > > >The FFI does not ensure any type consistency between the > >arguments to `Ptr'/`ForeignPtr' and the corresponding C > >types. > > I've been using 'Ptr Word8' with newArray to pass lists of byte

Re: Ptr and ForeignPtr Questions

At 2001-09-20 06:55, Manuel M. T. Chakravarty wrote: >The FFI does not ensure any type consistency between the >arguments to `Ptr'/`ForeignPtr' and the corresponding C >types. I've been using 'Ptr Word8' with newArray to pass lists of bytes to C functions. They appear as unsigned char arrays in

Re: Ptr and ForeignPtr Questions

Ashley Yakeley <[EMAIL PROTECTED]> wrote, > At 2001-09-19 23:45, Manuel M. T. Chakravarty wrote: > > >> What if the type is polymorphic (e.g. > >> declared as 'Storable a => Ptr a' rather than something like 'Ptr Word8')? > > > >Also possible, as the argument to `Ptr' is just dummy. > > What?

RE: Ptr and ForeignPtr Questions

At 2001-09-20 02:46, Simon Marlow wrote: >No, it's not safe. The reason is that the compiler can track a >ForeignPtr to discover when it dies, in order to run the finalizer, but >it can't track a Ptr. As soon as you drop all references to the >ForeignPtr then the finalizer will run, even if you

RE: Ptr and ForeignPtr Questions

> At 2001-09-20 02:14, Simon Marlow wrote: > > >I'll just add that the docs have been updated for 5.02, > > Do you have a URL for that? Not yet, but the release is imminent (really!) so it'll be up on the web site shortly. > >And don't forget that using foreignPtrToPtr is quite dangerous; much

Re: Ptr and ForeignPtr Questions

At 2001-09-20 02:31, I wrote: >int foo (char selector,char* arg) ... > if (selector == 200) I guess that should be int foo (unsigned char selector,char* arg) -- Ashley Yakeley, Seattle WA ___ Glasgow-haskell-users mailing list [E

RE: Ptr and ForeignPtr Questions

At 2001-09-20 02:14, Simon Marlow wrote: >I'll just add that the docs have been updated for 5.02, Do you have a URL for that? >And don't forget that using foreignPtrToPtr is quite dangerous; much >better to use withForeignPtr instead, otherwise you might find the >ForeignPtr being finalised ear

Re: Ptr and ForeignPtr Questions

At 2001-09-19 23:45, Manuel M. T. Chakravarty wrote: >> What if the type is polymorphic (e.g. >> declared as 'Storable a => Ptr a' rather than something like 'Ptr Word8')? > >Also possible, as the argument to `Ptr' is just dummy. What? What about 'withObject'? A Haskell 'Ptr a' is a C array-poi

RE: Ptr and ForeignPtr Questions

> Ashley Yakeley <[EMAIL PROTECTED]> wrote, > > > The documentation for FFI in the GHC user's guide seems to > be out of date > > with regard to passing Ptrs across. > > > > 1. My reference is > > > > (from >

Re: Ptr and ForeignPtr Questions

Ashley Yakeley <[EMAIL PROTECTED]> wrote, > The documentation for FFI in the GHC user's guide seems to be out of date > with regard to passing Ptrs across. > > 1. My reference is > > (from

Ptr and ForeignPtr Questions

The documentation for FFI in the GHC user's guide seems to be out of date with regard to passing Ptrs across. 1. My reference is (from ) Is this the latest documentation avail