On Thursday, 7 February 2013 at 10:15:49 UTC, Namespace wrote:
[code]
import std.stdio;
class Vec2 {
public:
short x, y;
this(short x, short y) {
this.x = x;
this.y = y;
}
}
void foo(Vec2 v) {
delete v;
}
void bar(Vec2 v) {
}
void main() {
foo(new Vec2(42, 23));
Vec2 v1 = new Vec2(4, 2);
foo(v1);
assert(v1 !is null);
writefln("v1.x = %d", v1.x);
Vec2 v2 = new Vec2(4, 2);
bar(v2);
writefln("v2.x = %d", v2.x);
}
[/code]
This code prints:
v1.x = 0
v2.x = 4
But is this correct? I expected
v1.x = 4
v2.x = 4
Same behaviour with destroy.
Well, given that you are reading a deleted/destroyed object, I'm
not sure why you'd expect *any* behavior at all. I'd simply
expect *undefined* behavior...
In any case, I think what you are seeing is a Vec2 instance init
state. If you change Vec2 to:
//----
class Vec2 {
public:
short x = 2, y = 2;
// ...
//----
Then the output becomes:
v1.x = 2
v2.x = 4
AFAIK, the delete/destroy *might* eagerly reset the object to its
init state, to make future re-use more efficient. I'm not sure,
but in any case, what you are observing is undefined, so I
wouldn't look too much into it...
