atomic AddUint32 overflow

Question

I'm using the below code to get unique IDs within process:

for i := 0; i < 10; i++ {
    go func() {
        for {
            atomic.AddUint32(&counter, 1)
            time.Sleep(time.Millisecond)
        }
    }()
}

What will happen if the counter value overflows uint32's limit?

Answer 1

The value wraps around, which is very easy to demonstrate:

u := uint32(math.MaxUint32)
fmt.Println(u)
u++
fmt.Println(u)


// or
u = math.MaxUint32
atomic.AddUint32(&u, 1)
fmt.Println(u)

https://play.golang.org/p/lCOM3nMYNc