Hello everyone,
In the ATL Internals book, one form of constructor of CComQIPtr is implemented as this,
I think there is a bug when QueryInterface fails, and the original value of member variable p is overwritten.Code:CComQIPtr (IUnknown* lp)
{
p = NULL; if (lp != NULL) lp -> QueryInterface (*piid, (void**)&p);
}
I found the in MSVC 2008, the implementation is,
Seems the bug is fixed? Is it a bug in old version of ATL or a bug in the book? :-)Code:atlcomcli.h
CComQIPtr(_In_opt_ IUnknown* lp) throw()
{
if (lp != NULL)
lp->QueryInterface(*piid, (void **)&p);
}
thanks in advance,
George