destructors and GC again

[Derek Parnell]

On Mon, 16 Oct 2006 15:34:22 -0500, Carlos Santander wrote:

> Sean Kelly escribió:
>> Lutger wrote:
>>> Sorry for this topic again, I'm still not exactly sure: when an 
>>> unreferenced object is collected during the lifetime of your program 
>>> (before main exits), is the destructor of this object guaranteed to be 
>>> called? I expect it to be so, as otherwise destructors seem pretty 
>>> useless (and dangerous), but cannot infer this from the spec.
>> 
>> When an object is collected by the GC, it's dtor will be called. 
>> However, the GC may not detect an orphaned object as collectable if 
>> there is a value in memory somewhere that "looks" like a reference to 
>> that object.
>> 
>> Sean
> 
> There's also the problem with global objects:
> 
> //-------------------------------------------
> import std.stdio;
> 
> class A
> {
>      ~this()
>      {
>          writefln("~A");
>      }
> }
> 
> A tmp;
> 
> void main()
> {
>      tmp=new A;
> }
> //-------------------------------------------
> 
> Nothing is printed.

Yes, this is my experience too. It also happens with objects stored in AA's
I think.  However, either of these fix the issue.

 void main()
 {
     auto tmp=new A;
 }

 . . . .

 void main()
 {
     auto tmp=new A;
     scope(exit) { delete tmp; }
 }

-- 
Derek Parnell
Melbourne, Australia
"Down with mediocrity!"