Introducing the New AtomicFlagMBS Class in MBS Xojo Plugins 25.2

With the release of MBS Xojo Plugins version 25.2, developers gain access to a powerful new class designed to help manage concurrency in a thread-safe, lock-free manner: the AtomicFlagMBS class. This lightweight atomic boolean type can be the foundation for building your own synchronization primitives like semaphores or critical sections — without relying on heavyweight system locks.

What is AtomicFlagMBS?

AtomicFlagMBS is a simple yet powerful tool for low-level concurrency control. It wraps a single atomic boolean value and provides atomic operations to read, set, and clear it. Because all operations are performed atomically, this class is safe to use across threads without the risk of data races.

Key Features:

Lock-free: No system-level locks or mutexes involved.
Cross-platform: Works on macOS, Windows, Linux, and iOS.
Lightweight: Ideal for high-performance, low-overhead synchronization.

Typical Use Case: Simple Spin Lock

One of the most common uses of an atomic flag is implementing a spin lock or lightweight lock mechanism:

Var f As New AtomicFlagMBS

// Try to acquire the lock
Var b As Boolean = f.TestAndSet
If Not b Then
  // Successfully acquired the lock
  Break

  // Perform your critical section work here

  // Release the lock
  f.Clear
Else
  // Lock already held
  Break
End If

The TestAndSet method atomically checks the current value of the flag and sets it to True. It returns the value that was previously held, allowing you to determine if you successfully acquired the lock.

Releasing the Lock

To release the lock, call the Clear method:

f.Clear

This sets the flag back to False, making it available again.

When Should You Use `AtomicFlagMBS`?

Use this class when:

You need lightweight, low-latency synchronization.
You’re implementing custom concurrency tools like semaphores or critical regions.
You want fine control over multi-threaded access without the cost of full-blown locking.