1 // Copyright 2017 The Go Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style 3 // license that can be found in the LICENSE file. 4 5 package mysync 6 7 import "runtime" 8 9 type WaitGroup struct { 10 Callers []uintptr 11 } 12 13 func (wg *WaitGroup) Add(x int) { 14 wg.Callers = make([]uintptr, 32) 15 n := runtime.Callers(1, wg.Callers) 16 wg.Callers = wg.Callers[:n] 17 } 18 19 func (wg *WaitGroup) Done() { 20 wg.Add(-1) 21 } 22
