What is the difference between Go's wait groups and barriers for synchronizing and coordinating multiple goroutines in Go programs?
Go's wait groups and barriers are both mechanisms for synchronizing and coordinating multiple goroutines in Go programs, but they have different use cases and behavior.
Wait groups are used to wait for a group of goroutines to finish before continuing execution. A wait group is a counter that is incremented when a new goroutine is started and decremented when it finishes. The main goroutine can wait for the counter to reach zero using the Wait method, which blocks until all goroutines have finished. Wait groups are useful for cases where multiple goroutines need to complete before the program can proceed, such as when waiting for a set of parallel computations to finish before collecting their results.
Barriers, on the other hand, are used to coordinate the execution of multiple goroutines at specific points in their execution. A barrier is a synchronization primitive that waits for a fixed number of goroutines to reach a specific point in their execution before allowing them to continue. Once the required number of goroutines has reached the barrier, they are all unblocked and allowed to continue executing. Barriers are useful for cases where multiple goroutines need to reach a certain point in their execution before proceeding, such as when synchronizing access to a shared resource.
In summary, wait groups are used to wait for the completion of multiple goroutines, while barriers are used to coordinate the execution of multiple goroutines at specific points in their execution.