>>> I have a predefined set of members, some of which are optional.
>> Having optional fields is also a good reason.
>
> What is the use of T_OBJECT_EX vs T_OBJECT in PyMemberDef then?
Right - this works for optional objects. However, it can't possibly
work for any of the other fields.
> I would
> have though that the former describes an optional field, because the
> behaviour of accessing it when it is NULL is the same as accessing a
> nonexistent field. However, I see that it still appears in the dir()
> output even if it is NULL, so it seems I'm misunderstanding this.
I suppose that's because there will still be a descriptor for the field
in the class.
> The 'example_attribute' can be accessed, but it is not visible in the
> dir() output. The code for this is below.
I see. So you do need a tp_members list:
static PyMemberDef example_members[] = {
{"__dict__", T_OBJECT, offsetof(Example, dict), READONLY},
{0}
};
Perhaps dir() should know about tp_dictoffset, but alas, it doesn't.
Regards,
Martin
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