[Python-Dev] Re: Suggested memory API rules for 2.3

Tim Peters tim.one@comcast.net
Thu, 04 Apr 2002 11:38:54 -0500

[Neil Schemenauer]
> People will have to cast to PyObject* when calling PyObject_GC_Del.

This depends on whether you want to leave its signature alone, or declare it
as taking a void*.

> I guess that will be consistent with the other _Free and _Del functions.

One reason I prefer the other _Free functions over their _Del versions is
that they're already declared to take void*, just like C free(); e.g.,

    extern DL_IMPORT(void) PyObject_Free(void *);

Some of our macros do redundant casts to void* now when invoking these guys.

In any case, if people stick to the "recommended" API {PyMem,
PyObject)_Free, they should not need to cast their arguments.

Note that there's no type safety in the way we've actually implemented
things even for the PyObject_Del spelling:

#define PyObject_Del(op) _PyObject_Del((PyObject *)(op))

That is, no matter what kind of goofy pointer a programmer may pass, we
silently cast it to PyObject* anyway.  Better then (IMO) to change
_PyObject_Del's signature to void*, let *it* cast to PyObject* internally,
and lose the macro trick.