Critical Sections and Read operations.

[Arjay]

I think both of you above me don't know that a race condition can't occur when there's 1 thread writing to 1 boolean and all other threads only read the boolean

Actually I understand this very well. If the shared resource is a boolean which can be changed in an atomic operation, then no race condition will occur. This is the one special case where no synchronizating is required.

However, every other variable (BOOL, int, string, etc), you will encounter a race condition if one thread writes while one or more threads are reading or writing.

When I answered this question, I'm not interested in talking about the one special case (i.e. boolean) where sharing a resource across threads works without synchronization.

Folks tend to find thread synchronizating hard enough as it is. To me, it's easier to try to list the rules where you need synchronization:

1) If at least one thread is writing while one or more threads are reading or writing, then you need synchronization.
2) If all threads only every read, then no synchronization is required.

It's easier to apply these rules to all variables/shared resources including a boolean type. For the boolean, synchronization isn't technically required, but doesn't hurt.

As far as boolean, I never use these sorts of flag variables anyway to signal the thread to perform some action. Instead I'll use a windows event. Advantages of using an events are they can be used in the WaitFor functions and they can be used across processes.