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digitalmars.D.learn - Get the address of an object, within the object itself

reply Andrew Chapman <nycran gmail.com> writes:
Hi all, sorry if this question is silly, but is it possible to 
get the address of an object within the object itself?

e.g.

class Node
{
     this()
     {
         writeln(&this);  // Doesn't work
     }
}

auto node = new Node();
writeln(&node); // Does work

Thanks very much,
Cheers,
Andrew.
Feb 15
next sibling parent Jonathan M Davis via Digitalmars-d-learn writes:
On Wednesday, February 15, 2017 21:27:00 Andrew Chapman via Digitalmars-d-
learn wrote:
 Hi all, sorry if this question is silly, but is it possible to
 get the address of an object within the object itself?

 e.g.

 class Node
 {
      this()
      {
          writeln(&this);  // Doesn't work
      }
 }

 auto node = new Node();
 writeln(&node); // Does work
This does _not_ give you the address of the Node object. It gives you the address of the reference. - Jonathan M Davis
Feb 15
prev sibling parent reply Jonathan M Davis via Digitalmars-d-learn writes:
On Wednesday, February 15, 2017 13:33:23 Jonathan M Davis via Digitalmars-d-
learn wrote:
 On Wednesday, February 15, 2017 21:27:00 Andrew Chapman via Digitalmars-d-
 learn wrote:
 Hi all, sorry if this question is silly, but is it possible to
 get the address of an object within the object itself?

 e.g.

 class Node
 {

      this()
      {

          writeln(&this);  // Doesn't work

      }

 }

 auto node = new Node();
 writeln(&node); // Does work
This does _not_ give you the address of the Node object. It gives you the address of the reference.
IIRC, the only way to get the address of the object itself would be to cast it to void*, but it's not something that I do normally, so I'd have to experiment a bit to be sure. - Jonathan M Davis
Feb 15
parent reply Andrew Chapman <nycran gmail.com> writes:
On Wednesday, 15 February 2017 at 21:37:12 UTC, Jonathan M Davis 
wrote:
 On Wednesday, February 15, 2017 13:33:23 Jonathan M Davis via 
 Digitalmars-d- learn wrote:
 On Wednesday, February 15, 2017 21:27:00 Andrew Chapman via 
 Digitalmars-d- learn wrote:
 Hi all, sorry if this question is silly, but is it possible 
 to get the address of an object within the object itself?

 e.g.

 class Node
 {

      this()
      {

          writeln(&this);  // Doesn't work

      }

 }

 auto node = new Node();
 writeln(&node); // Does work
This does _not_ give you the address of the Node object. It gives you the address of the reference.
IIRC, the only way to get the address of the object itself would be to cast it to void*, but it's not something that I do normally, so I'd have to experiment a bit to be sure. - Jonathan M Davis
Thanks Jonathan. Good point about the reference address. I can work around this quite easily, but I was curious. I will try the void* cast and see what happens. Cheers.
Feb 15
parent Jacob Carlborg <doob me.com> writes:
On 2017-02-15 22:42, Andrew Chapman wrote:

 Thanks Jonathan.  Good point about the reference address.  I can work
 around this quite easily, but I was curious.  I will try the void* cast
 and see what happens.
If it's only for printing you can use the C "printf" without any casting: import core.stdc.stdio; class Node { this() { printf("%p\n", this); } } void main() { new Node; } -- /Jacob Carlborg
Feb 16