Ashley Yakeley 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 always do this:

module MyModule where { foreign import StringCopy :: Ptr Int8 -> Ptr Int8 -> IO (); }

which autogenerates this header:

extern "C" { void MyModule__StringCopy(signed char* a,signed char* b); }

which the user can implement like this:

char* strcat(char* dest, const char* src);

void MyModule__StringCopy(char* dest,char* src) { strcat(dest,src); }

(assuming char and signed char are identical).

If you are writing a Haskell binding to a large C library that has hundreds of functions, it is extremely unattractive to write "impedance matchers" like `MyModule__StringCopy' manually. Manuel