[ctypes-users] Structure Wrap Wrong - access violation

[Mark L. <lar...@gm...>]

ctype users,

I'm attempting to call a CDLL with the following exported function:

[C CODE]

struct some_data{
	int size,degree,df,order;
	double *x, *y, lambda;
};

__declspec(dllexport) double *some_func(some_data*, char* );

[/C CODE]

My python looks like this:

[PYTHON]

class SOME_DATA(Structure):
    _fields_ = [("size", c_int),
                ("degree", c_int),
                ("df", c_int),
                ("order", c_int),
                ("lamb", c_double),
                ("x", POINTER(c_double)),
                ("y", POINTER(c_double))
                ]

libc = CDLL("path\to\dll")

x = [4, 4, 7, 7]
y = [2, 10, 4, 22]

someData = SOME_DATA()
someData .size = len(x)
someData .degree = 3
someData .df = 0
someData .order = 4
someData .lamb = 1.0
someData .x = (c_double * len(x))(*x)
someData .y = (c_double * len(y))(*y)

rvErr = c_char_p("")
_some_func= libc.some_func
_some_func.restype = POINTER(c_double)
_some_func(byref(someData),rvErr)

[/PYTHON]

When I run this I get:

WindowsError: exception: access violation reading 0x00000000

This is my first time using ctypes.  I'm sure I'm missing something obvious.

Thanks for taking a look,

Mark