Semaphore with Main Thread and Preemptive Thread

General
1

There was a long discussion in the betas about this topic: https://forum.xojo.com/t/criticalsection-semaphore-preemptive-thread-changes/81554/40

It’s probably good to revisit it here.

It sounds like you can’t have a Semaphore or CriticalSection that protects both a Cooperative and Preemptive thread at the same time.

But can you use a Semaphore or CriticalSection that protects a Preemptive Thread and the Main Thread? I’m not clear on this

2

Yes.

3

So does this mean that the Main thread, even though would cooperate and share time with other Cooperative threads, should not itself be thought of a “Cooperative Thread” ?

I think that’s where I’m getting confused.

Does this sound correct:

A Semaphore or CriticalSection can work with

  • The Main Thread and one or more Cooperative Threads
  • The Main Thread and one or more Preemptive Threads

But will not work with

  • A cooperative thread (which is not the Main thread) and one or more Preemptive Threads
1 Like
4

Correct.

5

I’ve logged the following case to see if anything can be done to improve the situation:

https://tracker.xojo.com/xojoinc/xojo/-/issues/77256

1 Like