Re: Overloading operator delete problem
"kanze" <kanze@gabi-soft.fr> writes:
[very useful elaboration of how all the operator news and deletes
interact]
It just occured to me that the classical placement new (as opposed to
the nothrows), doesn't follow that pattern. The following is obviously
illegal, ptr should be destroyed by a call to ~A.
int main()
{
A *ptr = (A*)malloc(sizeof(A));
ptr = new (ptr) A;
delete ptr;
free(ptr);
}
Also note that because the non-placement delete is called for normal
deletes, if you provide a special placement new of your own, you
also have to replace the non-placement operator delete, AND the
non-placement operator new, ensuring that in all of the operator
new's, you do something so that the non-placement operator delete
can tell how to dispose of the memory.
Or you provide a custom delete function for your type. Then you can't
delete them with delete, of course, but you also can't delete with
delete what you've allocated by classic placement new.
So actually we have:
allocated by | deleted by
new delete
new (nothrow) delete
new (void*) ~T
new (custom_t) custom-defined
Regards,
Jens
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