Re: [Haskell-cafe] FFI and struct arguments

17 Jul 2008


      Felipe Lessa wrote:
...
Hi,
I tried googling and searching the haskellwiki about this but wasn't
lucky enough. My question is: is there a way to send struct arguments
to C functions via the FFI or do I need to create a C wrapper? I guess
there isn't, and while I can live without it, I'd like to leave no
doubt.
Sometimes there is such a way. See below.
...
Details:
I have something like
====================
typedef struct vect {
    float x,y;
} vect;
void func(vect v);
For most architectures stack layout of

void func(vect v);

and

void func(float x, float y);

is exactly the same, so for FFI purposes this 'func' can be declared as 
something like:

foreign import ccall unsafe :: Float -> Float -> IO ()


Cheers,
Kyra

Re: [Haskell-cafe] FFI and struct arguments

kyra