Re: ref count
JD <jdt_young@yahoo.com> wrote:
In the following simple code, I don't need to call p1->Release() at
the end to make p1's ref. count back to zero. Am I right?
// Assume p1's ref. count is increased by 1 only at the beginning
// and p2's is never increased.
IUnknown *p1, *p2;
...
// assuming the current refence count of p1 is one right
// before the next assignment.
p2 = p1;
...
p2->Release();
You are right - you don't need to call p1->Release(). Essentially, you
make two ref-counting errors that cancel each other. This is allowed,
but be very careful.
The two errors I mentioned are as follows. By assigning p1 to p2, you
create an extra reference to the object, but you fail to increment
reference count. The refcount is now too low. By failing to call Release
on one of those references, you would normally make the refcount too
high, but since it is already low, everything evens out.
--
With best wishes,
Igor Tandetnik
With sufficient thrust, pigs fly just fine. However, this is not
necessarily a good idea. It is hard to be sure where they are going to
land, and it could be dangerous sitting under them as they fly
overhead. -- RFC 1925