BeginCriticalRegion - EndCriticalRegion

[=?Utf-8?B?Um9nZXI=?=]

Hi,

As I understand, if a code section inside a sub called with threadX.Start
is between BeginCriticalRe gion - EndCriticalRegi on, it should complete (at
least that portion of code, not the whole 'sub'... even if a TreadX.Abort is
used, if this portion of code is running when you call that Abort.

So With this program, I would expect to print :

I'm still standing, yeh yeh yéah
Main thread finished

But only

Main thread finished

appears because thread is aborted although The code between critical region
is running... Why ?

Code:


Sub Main()


Dim myThreadx As New Thread(AddressO f subWithASleep)
myThreadx.Start ()
Thread.Sleep(20 00) 'For the called thread to have some time to enter that
"begin-critical-region"

myThreadx.Abort ()
Console.WriteLi ne("Main thread finished")

end sub


Public Sub subWithASleep()

Thread.BeginCri ticalRegion()

Thread.Sleep(15 000) 'waits 15 seconds
Console.Write(" I'm still standing, yeh yeh yéah") 'It should show
but it does NOT !

Thread.EndCriti calRegion()

End Sub


--
Roger
..NET 2005 and DB developer

[=?Utf-8?B?UGV0ZXIgUml0Y2hpZSBbQyMgTVZQXQ==?=]

RE: BeginCriticalRe gion - EndCriticalRegi on

Are you confusing Critical Regions and Constrained Execution Regions?

BeginCriticalRe gion/EndCriticalRegi on is used to signify a critical region
of code--a region of code that non-atomically modifies data shared with other
threads. Interruption of code in critical region of code generally would
affect other threads. BeginCriticalRe gion/EndCriticalRegi on don't stop code
from being interrupted; it allows the host to decide what to do if a critical
region does get interrupted (like unload the AppDomain the code is in).

Manually specifying critical regions when using Monitor (and hence the
lock/SyncLock keywords) or Mutex appears largely redundant as Monitor and
Mutex already do this (as described by Jeffery Richter [1]; although I can
find no Microsoft documentation on this).

Are you trying to write a block of code that can't be interrupted?

[1]

http://msdn.microsoft.com/msdnmag/issues/06/03/concurrentaffairs/default.aspx

--
Browse http://connect.microsoft.com/VisualStudio/feedback/ and vote.

http://www.peterRitchie.com/blog/

Microsoft MVP, Visual Developer - Visual C#


"Roger" wrote:

Hi,
>
As I understand, if a code section inside a sub called with threadX.Start
is between BeginCriticalRe gion - EndCriticalRegi on, it should complete (at
least that portion of code, not the whole 'sub'... even if a TreadX.Abort is
used, if this portion of code is running when you call that Abort.
>
So With this program, I would expect to print :
>
I'm still standing, yeh yeh yéah
Main thread finished
>
But only
>
Main thread finished
>
appears because thread is aborted although The code between critical region
is running... Why ?
>
Code:
>
>
Sub Main()
>
>
Dim myThreadx As New Thread(AddressO f subWithASleep)
myThreadx.Start ()
Thread.Sleep(20 00) 'For the called thread to have some time to enter that
"begin-critical-region"
>
myThreadx.Abort ()
Console.WriteLi ne("Main thread finished")
>
end sub
>
>
Public Sub subWithASleep()
>
Thread.BeginCri ticalRegion()
>
Thread.Sleep(15 000) 'waits 15 seconds
Console.Write(" I'm still standing, yeh yeh yéah") 'It should show
but it does NOT !
>
Thread.EndCriti calRegion()
>
End Sub

[=?Utf-8?B?Um9nZXIgVHJhbmNoZXo=?=]

RE: BeginCriticalRe gion - EndCriticalRegi on

Thanks, Peter. I'll take a deeper look at this.

Bye,

--
Roger Tranchez
..NET 2005 and DB developer


"Peter Ritchie [C# MVP]" wrote:

Are you confusing Critical Regions and Constrained Execution Regions?
>
BeginCriticalRe gion/EndCriticalRegi on is used to signify a critical region
of code--a region of code that non-atomically modifies data shared with other
threads. Interruption of code in critical region of code generally would
affect other threads. BeginCriticalRe gion/EndCriticalRegi on don't stop code
from being interrupted; it allows the host to decide what to do if a critical
region does get interrupted (like unload the AppDomain the code is in).
>
Manually specifying critical regions when using Monitor (and hence the
lock/SyncLock keywords) or Mutex appears largely redundant as Monitor and
Mutex already do this (as described by Jeffery Richter [1]; although I can
find no Microsoft documentation on this).
>
Are you trying to write a block of code that can't be interrupted?
>
[1]

http://msdn.microsoft.com/msdnmag/issues/06/03/concurrentaffairs/default.aspx

>
>
--
Browse http://connect.microsoft.com/VisualStudio/feedback/ and vote.

http://www.peterRitchie.com/blog/

Microsoft MVP, Visual Developer - Visual C#
>
>
"Roger" wrote:
>

Hi,

As I understand, if a code section inside a sub called with threadX.Start
is between BeginCriticalRe gion - EndCriticalRegi on, it should complete (at
least that portion of code, not the whole 'sub'... even if a TreadX.Abort is
used, if this portion of code is running when you call that Abort.

So With this program, I would expect to print :

I'm still standing, yeh yeh yéah
Main thread finished

But only

Main thread finished

appears because thread is aborted although The code between critical region
is running... Why ?

Code:


Sub Main()


Dim myThreadx As New Thread(AddressO f subWithASleep)
myThreadx.Start ()
Thread.Sleep(20 00) 'For the called thread to have some time to enter that
"begin-critical-region"

myThreadx.Abort ()
Console.WriteLi ne("Main thread finished")

end sub


Public Sub subWithASleep()

Thread.BeginCri ticalRegion()

Thread.Sleep(15 000) 'waits 15 seconds
Console.Write(" I'm still standing, yeh yeh yéah") 'It should show
but it does NOT !

Thread.EndCriti calRegion()

End Sub

>