2 replies to this topic

[Corey Kosak]

This is my program. Each time I run it, it says "Sorry, didn't find existing item." It appears to not be persisting the EWR.

Should I expect ExtendedWeakReference to work?

using System;
using Microsoft.SPOT;

namespace hacks.netduino.sandbox {
  public class Program {
    public static void Main() {
      var oldValue=ExtendedWeakReference.RecoverOrCreate(typeof(Zamboni), 0,
        ExtendedWeakReference.c_SurvivePowerdown|ExtendedWeakReference.c_SurviveBoot);

      var blah=oldValue.Target as Blah;
      if(blah==null) {
        Debug.Print("Sorry, didn't find existing item");
        blah=new Blah();
      } else {
        Debug.Print("Existing value is "+blah.value);
      }
      ++blah.value;
      Debug.Print("new value is "+blah.value);
      oldValue.Target=blah;
    }
  }

  public class Zamboni { }

  public class Blah {
    public int value=0;
  }
}

[Chris Walker]

Hi Corey, ExtendedWeakReferences are not supported. We recommend using an SD card shield (or Netduino Plus with integrated SD) for data storage. All that said, we _could_ enable EWR support on the Netduino--but it would take up to 16KB of the available code space. Would that be worth it? Chris

[Corey Kosak]

Would that be worth it?

Nobody should do anything solely on my account, because I'm just playing around. But in a pony-complete world, the firmware would consult some kind of boot-time flag to decide whether that particular 16KB is allocated to code or EWR. Then, only EWR-using apps would have to pay this penalty.