Threading problem - Tell me what I'm seeing here.

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I'm trying to study for a cert and I'm writing a few examples loosely based
on Chapter 7 of the 536 manual. I am not used to thread programming. The
manual states that: 'Any attempt to abort a thread while it is within a
critical
region will have to wait until after the critical region is complete.' So,
I wrote the following class, used in a Dot Net 2.0 console app:

Imports System.Threading
Public Class Class5
Dim operation As New ThreadStart(AddressOf AbortThisThread)
Dim newThread As New Thread(operation)

Public Sub New()
newThread.Start()
Thread.Sleep(500)
newThread.Abort()
Console.WriteLine("In New, after abort, press any key...")
Console.ReadKey()
End Sub

Shared Sub AbortThisThread()
Try
Thread.BeginCriticalRegion()
Console.WriteLine("Class5:Thread: {0} in AbortThisThread sub",
Thread.CurrentThread.ManagedThreadId)
Console.ReadKey()
Console.WriteLine("In AbortThisThread, after ReadKey")
Thread.EndCriticalRegion()
Catch ex As ThreadAbortException
Console.WriteLine("Exception in AbortThisThread, error = " +
ex.Message)
End Try
End Sub

End Class

The output is as follows:

Class5:Thread: 10 in AbortThisThread sub
In New, after abort, press any key...
Exception in AbortThisThread, error = Thread was being aborted.

So it looks to me like I was able to interupt the critical region.

Comments? Am I making any sense at all? (Or does use of I/O invalidate
this begin/end scheme?)

[Steve Gerrard]

B. Chernick wrote:

I'm trying to study for a cert and I'm writing a few examples loosely
based on Chapter 7 of the 536 manual. I am not used to thread
programming. The manual states that: 'Any attempt to abort a thread
while it is within a critical
region will have to wait until after the critical region is
complete.' So, I wrote the following class, used in a Dot Net 2.0
console app:

Based on googling, that quote from the cert manual is incorrect. Critical
regions just indicate code that could leave an app's state corrupted if they are
aborted, allowing a host like SQL server to decide to restart the app.

There is a thing called a Constrained Execution Region that does defer an abort
until the end of the region. It also imposes severe restrictions on the content
of the region, including no IO.