In what modes does the mutex mechanism operate?

The mutual exclusion mechanism (Mutex) in Go operates in two main modes:

1. Locked — when one goroutine acquires the mutex, other goroutines attempting to acquire the same mutex are blocked and wait for it to be released.

2. Unlocked — when the mutex is free and available for acquisition.

Mutex provides exclusive access to shared resources, preventing multiple goroutines from executing critical sections of code simultaneously.

Example usage:

var mu sync.Mutex
var counter int

func increment() {
    mu.Lock()           // acquire the mutex
    defer mu.Unlock()   // release the mutex after execution
    counter++
}

Thus, the mutex operates in locking and unlocking modes, ensuring sequential access to data.