Hi,
we are converting a struct
typedef struct {
PyObject_HEAD
int first, second;
} intpair;
to a python class (similar to an example 25.2 in "Python in a Nutshell, 2nd Edition").
We, after PyInitialize() and importing the module in python, obtain a class, but __dict__ shows an empty doc string and also does not show the members "first" and "second".
The init function intpair_init (see below) does not seem to be called, since no printf debug statements are printed.
1) We suspect that we either initialise wrongly
2) or a problem with the fields in PyTypeObject being in the wrong order, something was left out etc.)
3) or ???
cheers
David, Juergen
We are using the PyTypeObject definition from /usr/lib/python2.5/doc/commontex/typestruct.h (see below):
and the functions intpair_dealloc,intpair_str, intpair_init.
static int intpair_init(PyObject *self , PyObject *args, PyObject *kwds)
{
static char* nams[] = {"first","second",NULL};
int first, second;
printf("1 in init\n");fflush(stdout);
if(!PyArg_ParseTupleAndKeywords(args, kwds, "ii", nams, &first, &second))
return -1;
((intpair*)self)->first = 101;
((intpair*)self)->second = 102;
printf("in init\n");
return 0;
}
with intpair_members:
static PyMemberDef intpair_members[] = {
{"first", T_INT, offsetof(intpair, first), 0, "first item" },
{"second", T_INT, offsetof(intpair, second), 0, "second item" },
{NULL}
};
the initialisation is done with:
void initintpair(void)
{
static PyMethodDef no_methods[] = { {NULL} };
PyObject* this_module = Py_InitModule("intpair", no_methods);
PyType_Ready(&t_intpair);
PyObject_SetAttrString(this_module, "intpair", (PyObject*)&t_intpair);
}
static PyTypeObject t_intpair = {
PyObject_HEAD_INIT(NULL)
0,
"intpair.intpair", /* For printing, in format "<module>.<name>" */
sizeof(intpair),
0, /* For allocation */
/* Methods to implement standard operations */
intpair_dealloc,
0,
0,
0,
0,
intpair_str,
/* Method suites for standard classes */
0,
0,
0,
/* More standard operations (here for binary compatibility) */
0,
0,
0,
PyObject_GenericGetAttr,
PyObject_GenericSetAttr,
/* Functions to access object as input/output buffer */
0,
/* Flags to define presence of optional/expanded features */
Py_TPFLAGS_DEFAULT,
"two ints (first,second)", /* Documentation string */
/* Assigned meaning in release 2.0 */
/* call function for all accessible objects */
0,
/* delete references to contained objects */
0,
/* Assigned meaning in release 2.1 */
/* rich comparisons */
0,
/* weak reference enabler */
0,
/* Added in release 2.2 */
/* Iterators */
0,
0,
/* Attribute descriptor and subclassing stuff */
0,
intpair_members,
0,
0,
0,
0,
0,
0,
intpair_init,
PyType_GenericAlloc,
PyType_GenericNew ,
_PyObject_Del, /* Low-level free-memory routine */
0,
0,
0,
0,
0,
0
};
