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
5package mysync
6
7import "runtime"
8
9type WaitGroup struct {
10	Callers []uintptr
11}
12
13func (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
19func (wg *WaitGroup) Done() {
20	wg.Add(-1)
21}
22