Threadsafe VB

[Guest]

I have a website written in VB.Net. I have a utility library where every
function is Shared and written in VB.Net. Now I wonder if my utility library
is thread safe.
In could rewrite my library in C# and use the lock keyword.
Or I could use J# and use the synchronized keyword.
What in heck, does a VB programmer do for threadsafety?

 

[TDAVISJR]

Public Static myVariable as Integer

SyncLock myVariable
myVariable = myVariable + 1
End SyncLock

 

[Guest]

Davis,
What if I need to synchronise more than one variable?
Can I simply nest a few synclocks?
Arne.

 

[TDAVISJR]

I don't see any reason why. You may want to do a search on SyncLock and see
what you find out. I haven't used it must so I'm not the expert on it

 

[Scott Allen]

Hi Arne:

You can nest SyncLocks - but it gets dangerous quickly if you are not
careful.

Let's say thread #1 takes a lock on object A, while thread #2 takes a
lock on object B. Both threads do some processing and then decide they
need some additional locks. Thread #1 tries to lock object B, while
thread #2 tries to lock object A. This is a deadlock scenario where
each thread is blocking and waiting for the other thread to release a
resource, but neither thread can release either.

A simple approach is to take a more granular lock. This limits
scalabiity somewhat but you'll have to measure and see if performance
under stress is acceptable.

 

[Kevin Spencer]

Locking is not the best option. Thread-Safety is. Why? Because if an object
is locked, every thread that wants access to it has to wait their turn. This
can lead to at the very least performance degradation, and at the most a
deadlock situation.

--
HTH,

Kevin Spencer
Microsoft MVP
..Net Developer
What You Seek Is What You Get.