Databases
StackOverflow2013
Postsdbo
PO.NET GC Accessing a synchronised object from a finalizer
 

Note that there are some explanatory texts on larger screens.

plurals
  1. PO.NET GC Accessing a synchronised object from a finalizer
    primarykey
    data
    text
    <p>I recently read this article <a href="http://msdn.microsoft.com/en-us/magazine/cc188793.aspx" rel="nofollow">Safe Thread Synchronization</a> as I was curious about the thread safety of calls made from a finaliser. I wrote the following code to test access to a static thread safe collection from a finaliser.</p> <pre><code>using System; using System.Collections.Generic; using System.Linq; using System.Text; namespace GCThreadTest { class Program { static class FinaliserCollection { private static Queue&lt;int&gt; s_ItemQueue = new Queue&lt;int&gt;(); private static System.Object s_Lock = new System.Object(); public static void AddItem(int itemValue) { lock(s_Lock) { s_ItemQueue.Enqueue(itemValue); } } public static bool TryGetItem(out int item) { lock(s_Lock) { if (s_ItemQueue.Count &lt;= 0) { item = -1; return false; } item = s_ItemQueue.Dequeue(); return true; } } } class FinaliserObject { private int m_ItemValue; public FinaliserObject(int itemValue) { m_ItemValue = itemValue; } ~FinaliserObject() { FinaliserCollection.AddItem(m_ItemValue); } } static void Main(string[] args) { int itemValueIn = 0; int itemValueOut = 0; while (itemValueOut &lt; 10000) { System.Threading.ThreadPool.QueueUserWorkItem (delegate(object value) { new FinaliserObject((int)value); System.Threading.Thread.Sleep(5); }, itemValueIn); itemValueIn = itemValueIn + 1; // This seems to stop finaliser from // being called? // System.Threading.Thread.Sleep(5); int tempItemValueOut = -1; if (FinaliserCollection.TryGetItem(out tempItemValueOut)) itemValueOut = tempItemValueOut; } System.Console.WriteLine("Finished after {0} items created", itemValueOut); System.Console.ReadLine(); } } } </code></pre> <p>Without the 'Sleep' call in the while loop this code seems to run fine but is it really safe from deadlocking? Would it ever be possible for a finaliser call to be made while a queued thread pool item is accessing the static collection? Why does adding the 'Sleep' to the main threads while loop appear to stop all finalisers from being called? </p>
    singulars
    1. PO
      singulars
      1. PTAnswer
    1. This table or related slice is empty.
    1. PTQuestion
    1. This table or related slice is empty.
    1. USkarmasponge
    plurals
    1. This table or related slice is empty.
    1. PL
      singulars
      1. LTLinked
    1. This table or related slice is empty.
    1. PO
      singulars
      1. PTAnswer
    1. VO
      singulars
      1. PO.NET GC Accessing a synchronised object from a finalizer
      1. This table or related slice is empty.
      1. VTUpMod
    1. This table or related slice is empty.
 

Querying!

 
Guidance
A row detail

Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

Related data can be related in a to-one or a to-many fashion. Captions of data related in a to-many fashion link to a list view showing a filtered view of the table.

Try moving around until you find a non-empty to-many entry and click on the label to get to one. You can move back to the root by clicking on the database name in the header.

SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).

Reload