Microsoft Certified Solutions Developer (MCSD) Certification Practice Test

What object is used to ensure threads arrive at a certain point before proceeding?

1. CountdownEvent

2. Mutex

3. Barrier

4. Semaphore

The correct answer is: Barrier

The object used to ensure that multiple threads arrive at a certain point before any of them can proceed is known as a Barrier. A Barrier is specifically designed for synchronization among a specified number of threads. When threads reach the barrier, they will wait until all participating threads have arrived. Once all specified threads have reached the barrier, they can then all proceed with their operations simultaneously. This mechanism is essential in scenarios where threads must complete some initialization tasks or computations before moving on to the next phase of execution. It helps in coordinating the execution flow, ensuring that resources are properly aligned before any further processing occurs. In contrast, CountdownEvent is more focused on tracking counts and signaling when a certain number of operations are complete. Mutex and Semaphore, while also synchronization objects, serve different purposes: Mutex is used to ensure exclusive access to a resource, while Semaphore is used for controlling access to a resource pool. These do not have the functionality of requiring all threads to wait for one another at a specific point in execution as the Barrier does.