Problem with unions and bitfields

Hi,

Ctypes behaves unexpectedly when attempting to access an anonymous union
containing bitfields.

I'm using hdr2py to convert a structure into a python module, the
generated python module looks ok, but in python 2.5.2 and 2.6.2 writing
the bitfields in the union splat other parts of the structure.

Header file:

/*
* WARNING: Autogenerated file, do not modify!
*/

#ifndef ___AUTO_STATS_MATRIX_RFILE_H
#define ___AUTO_STATS_MATRIX_RFILE_H

#include <stdint.h>

struct matrix_status_w0_t {
    uint32_t width : 8;
    uint32_t depth : 8;
    uint32_t reserved_future_1 : 16;
};

struct matrix_status_t {
    uint32_t rdata;
    uint32_t raddr;

    union {
        uint32_t                w0;
        matrix_status_w0_t      w0b;
        uint32_t reserved_future_1 : 16;
        uint32_t depth : 8;
        uint32_t width : 8;
    };
};

#endif

Example:

>>> import ctypes_testcase
>>> import ctypes
>>> u = ctypes_testcase.matrix_status_t()
>>> ctypes.sizeof(u)
12
>>> u.depth
0L
>>> u.raddr
0L
>>> u.depth = 4
>>> u.depth
4L
>>> u.raddr
1024L
>>> u.raddr = 0
>>> u.raddr
0L
>>> u.depth
0L

Am I doing something wrong of is this a bug in ctypes?

Thanks,

Chris


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