1 // run 2 3 // Copyright 2017 The Go Authors. All rights reserved. 4 // Use of this source code is governed by a BSD-style 5 // license that can be found in the LICENSE file. 6 7 package main 8 9 import ( 10 "fmt" 11 "runtime" 12 "sync/atomic" 13 "time" 14 ) 15 16 var a uint64 = 0 17 18 func main() { 19 runtime.GOMAXPROCS(2) // With just 1, infinite loop never yields 20 21 go func() { 22 for { 23 atomic.AddUint64(&a, uint64(1)) 24 } 25 }() 26 27 time.Sleep(10 * time.Millisecond) // Short sleep is enough in passing case 28 i, val := 0, atomic.LoadUint64(&a) 29 for ; val == 0 && i < 100; val, i = atomic.LoadUint64(&a), i+1 { 30 time.Sleep(100 * time.Millisecond) 31 } 32 if val == 0 { 33 fmt.Printf("Failed to observe atomic increment after %d tries\n", i) 34 } 35 36 } 37
