[Pyobjc-dev] FFI problems

[Ronald O. <ron...@xs...>]

It looks like I've run into a bug in libffi, or (more likely) I should 
dig for more documentation. The following program works fine when 
RETTYPE is int and crashes when RETTYPE is double. Problem is that this 
is how we use libffi in the bridge, the effect of this is that you 
cannot define methods that return anything other than id, char, short 
or int (and unsigned variants) at the moment. Luckily returning other 
types (double, long long, structs) is not that common in Cocoa.

Ronald

#include <ffi.h>
#include <assert.h>

#define RETTYPE double

static void closure_test_fn4(ffi_cif* cif,void* resp,void** args,
                              void* userdata)
{
         *(RETTYPE*)resp = 42;
}

typedef RETTYPE (*closure_test_type4)(void);

void doit(void)
{
         ffi_cif cif;
         ffi_type* cl_arg_types[17];
         static ffi_closure cl;
         double res;

         cl_arg_types[0] = NULL;

         /* Initialize the cif */
         assert(ffi_prep_cif(&cif, FFI_DEFAULT_ABI, 0,
         &ffi_type_sint, cl_arg_types) == FFI_OK);

         assert(ffi_prep_closure(&cl, &cif, closure_test_fn4,
         (void *) 3 /* userdata */)  == FFI_OK);
         res = ((closure_test_type4)(&cl))();
         printf("%f\n", res);
}


int main(void)
{
         doit();
}