Generating Function Prototypes

[Ashley Yakeley]

At 2002-07-03 02:57, Malcolm Wallace wrote:

>The "proper" way to do it is to write the prototype yourself in a
>C header file (or use an existing header), and then use a compiler-specific
>mechanism to #include it.

OK I'll do this.

>The nhc98 compiler does generate a prototype (ghc does not).  However,
>although this works quite well in the general case, occasionally the
>generated prototype may not be compatible with the real C type of
>the function (e.g. it cannot guess the `const' attribute).

This might be fixed by creating a ConstPtr type. Class Storable could 
then be extended:

    class Storable a where
        ...
        constPeekElemOff :: ConstPtr a -> Int -> IO a
        constPeekByteOff :: ConstPtr a -> Int -> IO a
        constPeek  :: ConstPtr a -> IO a

    castToConst   :: Ptr a -> ConstPtr a
    castAwayConst :: ConstPtr a -> Ptr a  -- possibly unsafe


-- 
Ashley Yakeley, Seattle WA