Dear list,
I suggest to insert an assertion before calling Py_DECREF/Py_XDECREF
which ensures that the reference count before the call is larger than
zero. Otherwise, this means that a PyObject that has already been
destroyed is planned to be destroyed a second time - which will not
happen, as the reference count is of unsigned integer type, and so it
will become a very large number - but it keeps a PyObject alive that
references destroyed memory.
I suggest to insert such assertions, because this easily detectable
programming error is hard to track based on a possibly resulting
segmentation fault at some later point during program execution (as has
happened to me). Maybe this would be detected by a debug-build of
Python, but in my environment, it would be troublesome to link it,
together with providing possibly needed debug-builds of other Python
extension packages (e.g. NumPy).
Thus, I suggest to insert
assert( Py_REFCNT(m_ptr) > 0 );
at the beginning of
api::object_base::~object_base()
and
void decref(T* p)
and to insert
assert( p == nullptr || Py_REFCNT(python::upcast<PyObject>(p)) > 0 );
at the beginning of
void xdecref(T* p)
Cheers,
Willi.
--
_____ _____ _____ Technische Universität Wien
DI Wilfried Karel /____// ___// / Dept. of Geodesy & Geoinform.
wilfried.karel@ // __ / /__ / // / Research Groups Photogrammetry
geo.tuwien.ac.at //__/// /__ / // / & Remote Sensing
+43 1 58801 12244 /____//____//____/ Gusshausstr. 27-29, A-1040 Wien
_______________________________________________
Cplusplus-sig mailing list
Cplusplus-sig@python.org
https://mail.python.org/mailman/listinfo/cplusplus-sig
