How does a blocking barrier operation differ from a standard synchronization operation?

A blocking barrier operation is a special synchronization mechanism that forces multiple threads or tasks to wait for each other at a certain point in execution before continuing.

Differences from standard synchronization operations:

• A barrier blocks all participating threads until all have reached this point. This guarantees that no thread proceeds further until all are ready.
• Standard synchronization operations (e.g., mutexes or semaphores) usually control access to resources but do not necessarily require all threads to synchronize at a single point.

Example: if you have 3 threads and want them all to perform some work, then simultaneously move to the next stage, use a barrier. Each thread will call the barrier operation and wait until all others have also called it.

In iOS, for such purposes, you can use DispatchBarrier in GCD, which blocks the execution of other tasks in the queue until the current one finishes.