我試圖了解golang通道和同步。當(dāng)我使用種族檢測器運(yùn)行我的程序時，它會導(dǎo)致種族檢測。我的程序：func main() { ch := make(chan int) done := make(chan struct{}) wg := sync.WaitGroup{} go func() { defer close(ch) defer close(done) wg.Wait() done <- struct{}{} }() for i := 0; i < 5; i++ { x := i wg.Add(1) go func() { defer wg.Done() fmt.Println("Value: ", x) ch <- x }() } loop: for { select { case i := <-ch: fmt.Println("Value: ", i) case <- done: break loop } }}比賽檢測報(bào)告：==================WARNING: DATA RACEWrite at 0x00c000020148 by goroutine 7: internal/race.Write() /home/linuxbrew/.linuxbrew/Cellar/go/1.16.5/libexec/src/internal/race/race.go:41 +0x125 sync.(*WaitGroup).Wait() /home/linuxbrew/.linuxbrew/Cellar/go/1.16.5/libexec/src/sync/waitgroup.go:128 +0x126 main.main.func1() /home/reddy/code/github.com/awesomeProject/prod.go:106 +0xc4Previous read at 0x00c000020148 by main goroutine: internal/race.Read() /home/linuxbrew/.linuxbrew/Cellar/go/1.16.5/libexec/src/internal/race/race.go:37 +0x206 sync.(*WaitGroup).Add() /home/linuxbrew/.linuxbrew/Cellar/go/1.16.5/libexec/src/sync/waitgroup.go:71 +0x219 main.main() /home/reddy/code/github.com/awesomeProject/prod.go:112 +0x124Goroutine 7 (running) created at: main.main() /home/reddy/code/github.com/awesomeProject/prod.go:103 +0x104==================我無法弄清楚這里出了什么問題。我的分析：wg.Add(1)正在遞增計(jì)數(shù)器wg.Done()在 goroutine 的末尾調(diào)用，這會遞減計(jì)數(shù)器ch <- x這應(yīng)該是一個阻塞調(diào)用，因?yàn)樗欠蔷彌_通道循環(huán)應(yīng)該迭代，直到完成通道有一些消息，當(dāng)計(jì)數(shù)器變?yōu)榱銜r發(fā)生，即所有5個goroutines都發(fā)布了消息waitgroup一旦計(jì)數(shù)器變?yōu)榱悖琯oroutine將恢復(fù)并完成被調(diào)用，一旦消息在主循環(huán)中被消耗，它就會中斷循環(huán)并應(yīng)優(yōu)雅地退出。wg
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TA貢獻(xiàn)1829條經(jīng)驗(yàn) 獲得超6個贊
該程序在調(diào)用wg之間有一場競賽。添加并調(diào)用 wg。等等。這些調(diào)用可以按任何順序發(fā)生。在調(diào)用 之前，調(diào)用 時不等待任何 goroutines。wg.Waitwg.Waitwg.Add
通過在啟動調(diào)用 的 goroutine 之前將調(diào)用移動到 進(jìn)行修復(fù)。此更改可確保在調(diào)用 之前進(jìn)行調(diào)用。wg.Addwg.Waitwg.Addwg.Wait
for i := 0; i < 5; i++ {
x := i
wg.Add(1)
go func() {
defer wg.Done()
fmt.Println("Value: ", x)
ch <- x
}()
}
go func() {
defer close(ch)
defer close(done)
wg.Wait()
done <- struct{}{}
}()
該類型具有在競賽檢測器下運(yùn)行時檢查此錯誤的代碼（建模讀取，建模寫入）。WaitGroup
通過在關(guān)閉時中斷主 goroutine 中的循環(huán)來簡化代碼。不需要該通道。chdone
ch := make(chan int)
wg := sync.WaitGroup{}
for i := 0; i < 5; i++ {
x := i
wg.Add(1)
go func() {
defer wg.Done()
fmt.Println("Value: ", x)
ch <- x
}()
}
go func() {
wg.Wait()
close(ch)
}()
for i := range ch {
fmt.Println("Value: ", i)
}
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