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Thread synchronization.

Author
16 Nov 2006 1:58 AM
Blake
Heya Group.

I am hoping that someone can help me understand how to use Synclock
properly. I am a tad confused. I have a class that is instanced on
multple threadpool threads, and uses shared members to track the state
shared by all instances.

The web is littered with examples of people using ...

Synclock GetType(MyClass)
    ' Do something to shared class members.
End Synclock

.... to access static members when many threads may own instances of the
class.

I understand that is dangerous because the type object may be locked
from outside the object causing deadlocks, and I am led to believe that
a private locking object is the way to go.

So should I do something like this;

Private Shared _lockObject As Object
....
Synclock _lockObject
    ' Do something to shared class members.
End Synclock

Or should I be locking on a type rather than an instance?

Thanks.

Author
16 Nov 2006 6:09 AM
Tom Shelton
Blake wrote:
Show quoteHide quote
> Heya Group.
>
> I am hoping that someone can help me understand how to use Synclock
> properly. I am a tad confused. I have a class that is instanced on
> multple threadpool threads, and uses shared members to track the state
> shared by all instances.
>
> The web is littered with examples of people using ...
>
> Synclock GetType(MyClass)
>     ' Do something to shared class members.
> End Synclock
>
> ... to access static members when many threads may own instances of the
> class.
>
> I understand that is dangerous because the type object may be locked
> from outside the object causing deadlocks, and I am led to believe that
> a private locking object is the way to go.
>
> So should I do something like this;
>

One correction, make sure initialize the instance :)

Private Shared _lockObject As New Object
                                              ^^^^
> ...
> Synclock _lockObject
>     ' Do something to shared class members.
> End Synclock
>
> Or should I be locking on a type rather than an instance?
>
> Thanks.

Look on a private shared object that you create (your second exampl) -
never lock on the type.  That is a result of some bad MSDN examples...

--
Tom Shelton