Carl Banks <pavlovevidence <at> gmail.com> writes:
...
> You can determine the offset the of the slot in the object structure
> by
> querying the member descriptor of the type object.
That sounds like just the kind of thing we were looking for - thanks!
> descr = GetAttrString(cls,"varname");
> offset = descr->d_member->offset;
> slotvar = (PyObject*)(((char*)obj)+offset)
Unfortunately, I am inexperienced at this kind of thing, so I wasn't
able to get something working. Maybe someone could tell me what's
wrong with the code below (it gives the error "'struct _object' has no
member named 'd_member'")?
PyObject *descr = PyObject_GetAttrString(x,"attr_one");
int offset = descr->d_member->offset;
PyObject* slotvar = (PyObject*)(((char*)obj)+offset);
where x is the class and attr_one is a slot (the full example is
appended to this message). I guessed the type of offset; I'm not sure
what it should be.
I couldn't find any information about d_member on the web.
> There might be some macros to simplify this.
Sorry to say that I also have no idea about where to find such macros!
Maybe I should continue this thread on capi-sig?
Thanks for your help,
Chris
class MyObject(object):
__slots__ = ['attr_one']
def __init__(self,attr_one=1.0):
self.attr_one = attr_one
import weave
def test():
x = MyObject
code = """
PyObject *descr = PyObject_GetAttrString(x,"attr_one");
int offset = descr->d_member->offset;
//PyObject* slotvar = (PyObject*)(((char*)obj)+offset);
"""
weave.inline(code,['x'],local_dict=locals(),verbose=1)
test()
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