Re: Destructor nonsense on dlang.org

[Tove]

On Thursday, 24 May 2012 at 20:53:33 UTC, Tove wrote:
On Thursday, 24 May 2012 at 19:46:07 UTC, foobar wrote:
Looks to me like an issue with separation of concerns. I think 
that dtors need to only provide deterministic management of 
resources and not affect GC algorithms:
1. classes should *not* have dtors at all.
2. struct values should *not* be gc managed [*].

Why not simply set "BlkAttr.NO_SCAN" on ourselves if we need 
certain resources in the destructor? Assuming we one day get 
user defined attributes, it can be make quite simple...

Tested my idea... unfortunately it's broken...

GC.collect() while the program is running, is OK... so I was 
hoping to add:
GC.disable() just before main() ends, but apparently this request 
is ignored.

i.e. back to square 1, undefined collecting order once the 
program exits.

import std.stdio;
import core.memory;

class Important
{
  this()
  {
    us ~= this;
  }
  ~this()
  {
    writeln("2");
  }

private:
  static Important[] us;
}

class CollectMe
{
  Important resource;

  this()
  {
    resource = new Important();
  }
  ~this()
  {
    writeln("1");
    clear(resource);
  }
}

void main()
{
  GC.setAttr(cast(void*)new CollectMe(), GC.BlkAttr.NO_SCAN);
  GC.collect();
  GC.disable();

  writeln("3");
}