這是我正在玩的 Golang 程序，只是為了讓我的概念正確。當(dāng)我運(yùn)行程序時(shí)它死鎖我不明白為什么？請任何人指出出了什么問題？package mainimport ( "fmt" "sync")var wg sync.WaitGroupfunc main() { numOfGoRoutines := 10 wg.Add(numOfGoRoutines) ch := make(chan int, numOfGoRoutines) for i := 0; i < numOfGoRoutines; i++ { a := i go sqr(ch, a, wg) } wg.Wait() fmt.Println("After WAIT") close(ch) var res int for i := range ch { res += i } ch = nil fmt.Println("result = ", res)}func sqr(ch chan int, val int, wg sync.WaitGroup) { fmt.Println("go - ", val) s := val * val ch <- s wg.Done()}輸出是：warning: GOPATH set to GOROOT (C:\\Go) has no effectgo - 9go - 0go - 1go - 2go - 3go - 4go - 5go - 6go - 7go - 8fatal error: all goroutines are asleep - deadlock!goroutine 1 [semacquire]:sync.runtime_Semacquire(0x5bcabc) C:/Go/src/runtime/sema.go:47 +0x2dsync.(*WaitGroup).Wait(0x5bcab0) C:/Go/src/sync/waitgroup.go:127 +0xbbmain.main() C:/demo/go-work/main.go:20 +0xdfexit status 2
1 回答
慕絲7291255
TA貢獻(xiàn)1859條經(jīng)驗(yàn) 獲得超6個(gè)贊
問題是您將副本傳遞sync.WaitGroup給 goroutine，而不是引用（即指針）：
package main
import (
"fmt"
"sync"
)
var wg sync.WaitGroup
func main() {
numOfGoRoutines := 10
wg.Add(numOfGoRoutines)
ch := make(chan int, numOfGoRoutines)
for i := 0; i < numOfGoRoutines; i++ {
a := i
go sqr(ch, a, &wg)
}
wg.Wait()
fmt.Println("After WAIT")
close(ch)
var res int
for i := range ch {
res += i
}
ch = nil
fmt.Println("result = ", res)
}
func sqr(ch chan int, val int, wg *sync.WaitGroup) {
fmt.Println("go - ", val)
s := val * val
ch <- s
wg.Done()
}
此外，由于wg是一個(gè)全局變量，您可以完全刪除該參數(shù)：
package main
import (
"fmt"
"sync"
)
var wg sync.WaitGroup
func main() {
numOfGoRoutines := 10
wg.Add(numOfGoRoutines)
ch := make(chan int, numOfGoRoutines)
for i := 0; i < numOfGoRoutines; i++ {
a := i
go sqr(ch, a)
}
wg.Wait()
fmt.Println("After WAIT")
close(ch)
var res int
for i := range ch {
res += i
}
ch = nil
fmt.Println("result = ", res)
}
func sqr(ch chan int, val int) {
fmt.Println("go - ", val)
s := val * val
ch <- s
wg.Done()
}
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