locking - C# waiting for an counter value fails -

locking - C# waiting for an counter value fails -

i've got fragment of code uses callback modify counter value other thread. i'm using lock , empty while loop checking if counter == 0. works when running in visual studio. however, after "releasing" , running binary freezes. while loop presented below, callback method body.

what may causing it?

thanks,

public void somemethod() { //starting bunch of threads calling callback method while(counter > 0) {} } public void callback() { lock (this) { countdown--; } }

locks needed every time access variable shared between threads, not in 1 location. in case code in while loop not introducing memory barrier when accessing counter , such jitter allowed create optimizations such reading cached version of value, or noticing value can't have been written , avoiding repeating read ever.

in specific case utilize volatile.read(ref counter) , work, should very wary of trying utilize lock-free or low-lock programming, or using these low level synchronization primitives. should strive instead utilize higher level synchronization primitives. in specific case semaphore appropriate. initialize inverse of countdown value, release in callback, , wait in method.

locking on implicit parameter (this) code smell. should strive ever lock on objects in small, rigidly controlled, scope, avoid deadlocks result of locks beingness taken out on object wide scope of code base.

c# locking