> Afaik, when overloading 'placement' new and delete
> like that, the only time the corresponding overload
> of delete will be called is if the constructor throws.
> All other times you have to call the destructor and
> the right version of delete yourself.
This is not true. If a class implements operator new and delete, they are
called to allocate and deallocate memory. Don't forget you can overload
"placement" new (a term which itself is "overloaded") with arbitrary
parameters, and this is what Xerces-C does.
Take a look at the file XMemory.hpp and note the various overloads for
operator new. You will see there is one that takes a size_t and a pointer
to a MemoryManager instance. This is the one that's called when doing
"placement" new with a pointer to a MemoryManager instance.
This overload of operator delete is the one that's called if the
constructor throws:
void operator delete(void* p, MemoryManager* memMgr);
This is the one that's called by the delete expression, and is the one
that retrieves the pointer the MemoryManager instance, and frees the
allocated memory:
void operator delete(void* p, MemoryManager* memMgr);
The implementation of these functions in XMemory.cpp will clarify what is
happening.
> > Often, when I see a crash in freeing memory, I discover that the crash
> > is a symptom of a previous bad transaction with the heap, like
> > deleting a pointer that's already been deleted.
>
> True, but in this case Purify isn't showing anything suspicious.
Can you should set some breakpoints and make note of the address that's
returned from MemoryManagerImpl::allocate() for this object, and verify
the same address is passed to MemoryManagerImpl::deallocate()?
You might also want to try a small test program that creates an instance
of IGXMLScanner, then deletes it, to verify something is completely broken
with the code. I used Xerces-C 2.3 extensively, and never had this
problem, but perhaps you have a corrupted library, or you're using a
different compiler and there's a bug.
Dave
---------------------------------------------------------------------
To unsubscribe, e-mail: [EMAIL PROTECTED]
For additional commands, e-mail: [EMAIL PROTECTED]
