On 06/03/2017 03:38 PM, Mark wrote:

> Ok. So by using '==' it should compare the addresses of the objects?

That's the default behavior. You can change it with opEquals:

  http://ddili.org/ders/d.en/object.html#ix_object.opEquals

I think you want to use the 'is' operator:

  http://ddili.org/ders/d.en/class.html#ix_class.is,%20operator

It's better because 'is' can be used with null variables.

> about 45 lines, that might be a lot of code
> for a post.

Yeah. Minimal is good. :)

> how Can I obtain the actual memory address of a class?

You mean the memory address of a class object. ;) It's achieved with the special semantics of casting the class variable to void*:

class C {
    int i;
}

void info(C o) {
    import std.stdio;
    writefln("  Object at %s,\n" ~
             "i member at %s\n", cast(void*)o, &o.i);
}

void main() {
    auto a = new C();
    auto b = new C();

    a.info();
    b.info();
}

Sample output on my system:

  Object at 7F810AA53060,
i member at 7F810AA53070

  Object at 7F810AA53080,
i member at 7F810AA53090

The difference of 16 bytes are from vtbl pointer and the monitor. (I think the latter is a kind of a lizard, which nobody actually uses. :p)

Ali

On Saturday, 3 June 2017 at 23:32:44 UTC, Ali Çehreli wrote:
...
> Ali

Awesome, that might be handy in the near future.

Thanks.

On Sat, Jun 03, 2017 at 10:38:31PM +0000, Mark via Digitalmars-d-learn wrote: [...]
> Ok. So by using '==' it should compare the addresses of the objects?
[...]

No, `==` is for comparing the *contents* of the objects.  You need to implement opEquals() for the objects being compared in order to define how the contents will be compared.

If you want to compare *addresses*, use `is`:

	Object a = new Object(...);
	Object b = a;	// b is a reference to the same object as a

	assert(b is a);

In this case there is no need to implement anything else, since comparing addresses is simple.


T

-- 
"No, John.  I want formats that are actually useful, rather than over-featured megaliths that address all questions by piling on ridiculous internal links in forms which are hideously over-complex." -- Simon St. Laurent on xml-dev