Extract the fields of a C struct

If you compile your C code with debugging (-g), pahole (git) can give you the exact structure layouts being used.

$ pahole /bin/dd…struct option {        const char  *              name;                 /*     0     8 */        int                        has_arg;              /*     8     4 */        /* XXX 4 bytes hole, try to pack */        int *                      flag;                 /*    16     8 */        int                        val;                  /*    24     4 */        /* size: 32, cachelines: 1, members: 4 */        /* sum members: 24, holes: 1, sum holes: 4 */        /* padding: 4 */        /* last cacheline: 32 bytes */};…

This should be quite a lot nicer to parse than straight C.

Regular expressions would work great about 90% of the time and then cause endless headaches for the remaining 10%.

The headaches happen in the cases where the C code contains syntax that you didn't think of when writing your regular expressions. Then you go back and realise that C can't really be parsed by regular expressions, and life becomes not fun.

Try turning it around: define your own simple format, which allows less tricks than C does, and generate both the C header file and the Python interface code from your file:

define socketopts    int16 port    int32 ipv4address    int32 flags

Then you can easily write some Python to convert this to:

typedef struct {    short port;    int ipv4address;    int flags;} socketopts;

and also to emit a Python class which uses struct to pack/unpack three values (possibly two of them big-endian and the other native-endian, up to you).

Have a look at Swig or SIP that would generate interface code for you or use ctypes.