On Friday, 25 January 2019 at 20:31:29 UTC, H. S. Teoh wrote:
On Fri, Jan 25, 2019 at 08:12:33PM +0000, Q. Schroll via
Digitalmars-d-learn wrote:
Say I have a class C and I want a pointer to a C handle.
Note that taking the address of `C` will actually give you a
pointer to the reference, not the pointer to the class instance
itself.
I know. This is precisely the thing I asked for: A pointer to a
handle. I called it handle for exactly this reason.
For that to be valid, you'll need to store your class reference
somewhere first, since it's invalid to take the address of an
rvalue
Yes. `&new C(...)` looked to wrong for me to even consider trying.
C c = new C(...);
C* ptrToRef = &c;
So the answer is no. At least not that simple.
Be warned that the pointer will become invalid when the
reference `c` goes out of scope, even if the object itself is
still live (via another reference), because the pointer is
pointing to the class reference rather than the actual object.
That's kind of obvious if you get remembered, but thanks. I
wasn't considering this as I wanted the handle to live on the
heap anyway --- the same way for a struct `S`, the pointer
pointed to by `S** ptr = new S*(new S(...));` lies on the heap.
I'll use
C* ptr = &[ new C(...) ][0];
for now. It looks ugly, but it does the job.
