Databases
StackOverflow2013
Postsdbo
PO
 

Note that there are some explanatory texts on larger screens.

plurals
  1. PO
    primarykey
    data
    text
    <p>With a contrived test, you can prove anything.</p> <p>All you have proved is that with <em>the code you wrote for your test</em>, <code>Thread.Abort</code> seems to work fine.</p> <p>The problem is, however, that as soon as you start using things that needs to be disposed of, all hope is lost.</p> <p>For instance, try this code:</p> <pre><code>using (Stream stream = new FileStream(@"C:\Test.txt", FileMode.Create, FileAccess.ReadWrite, FileShare.None)) { Thread.Sleep( Random.Next( 45, 55 ) ); } </code></pre> <p>Now, run this for a while and tell me if that still works.</p> <p>The problem appears when the code has left your sleep-call, and is inside the implicit finally-block for the using-block, and is just about to close your stream, and then you abort it.</p> <p>The problem with <code>Thread.Abort</code> is that it can happen <em>anywhere</em>, even within code that isn't supposed to throw exceptions.</p> <p>For instance, do you really expect the following code to crash <em>after</em> the if-expression has been evaluated, but <em>before</em> the <code>Dispose</code>-call has gone through?</p> <pre><code>if (_ObjectToDispose != null) { _ObjectToDispose.Dispose(); _ObjectToDispose = null; } </code></pre> <p>What if it happens right after the call to <code>.Dispose</code>? The field will still have a non-null value, which could lead to subtle problems elsewhere.</p> <p>What if you do this:</p> <pre><code>IDisposable objectToDispose = Interlocked.Exchange(ref _ObjectToDispose, null); if (objectToDispose != null) objectToDispose.Dispose(); </code></pre> <p>With this code, you grab the value, replaces it with null, and then before you get around to calling Dispose, your <code>ThreadAbortException</code> happens, which will just leave the object.</p> <p>Let me just drive the point home:</p> <blockquote> <p><strong>Thread.Abort should <em>never</em> be used, except in scenarios where you need to terminate the program (or tear down a custom AppDomain with threads running in it). You should <em>never</em> call Thread.Abort and then continue running.</strong></p> </blockquote> <p>Unless you need to plan bugs into your future schedule. In that case, go right ahead and use <code>Thread.Abort</code>, because I can almost guarantee you will have problems.</p>
    singulars
    1. This table or related slice is empty.
    1. PO.NET Thread.Abort again
      singulars
      1. PTQuestion
    1. PTAnswer
    1. USPeter Mortensen
    1. USLasse Vågsæther Karlsen
    plurals
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. PO.NET Thread.Abort again
      singulars
      1. PTQuestion
    1. This table or related slice is empty.
    1. VO
      singulars
      1. PO
      1. This table or related slice is empty.
      1. VTUpMod
    2. VO
      singulars
      1. PO
      1. This table or related slice is empty.
      1. VTAcceptedByOriginator
    3. VO
      singulars
      1. PO
      1. This table or related slice is empty.
      1. VTUpMod
    1. COI tried to run code you mentioned with file opening, and yes at some point after new thread's being created file is still busy with another thread which should be aborted really, but what if threads won't use shared resources? Seems it just proves that thread Abort is somewhat not safe. Even if I just need to terminate application couldn't Abort lead to process hang or some memory leak if some unmanaged code was running? In my case I needed something that can limit process running time to exact timeout limit, and in my case I can't control this process execution. Any ideas on this case?
      singulars
      1. PO
      1. UShoodoos
    2. COYou should pose a different question on SO, how to limit execution time, and then post what you intend to do in that code. In some cases, it won't be possible to do what you want if the code is busy in unmanaged code, as an example. The only "safe" way to do that would be to spawn a sub-process that terminates completely after the timeout has elapsed.
      singulars
      1. PO
      1. USLasse Vågsæther Karlsen
    3. COSmall correction (even though this answer is over a year old) Threads aren't abortable inside catch and finally blocks. So assuming a well-written finally block or using using blocks, the above example isn't really an issue.
      singulars
      1. PO
      1. USSteve
 

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