// A WaitGroup waits for a collection of goroutines to finish.// The main goroutine calls Add to set the number of// goroutines to wait for. Then each of the goroutines// runs and calls Done when finished. At the same time,// Wait can be used to block until all goroutines have finished.//// A WaitGroup must not be copied after first use.type WaitGroup struct { noCopy noCopy // 64-bit value: high 32 bits are counter, low 32 bits are waiter count. // 64-bit atomic operations require 64-bit alignment, but 32-bit // compilers do not ensure it. So we allocate 12 bytes and then use // the aligned 8 bytes in them as state. state1 [12]byte sema uint32}
示例代码:
package main import ( "sync" "fmt" ) func doWorker(id int, ch chan int, wg *sync.WaitGroup) { for n := range ch { fmt.Printf("Worker %d received %c\n", id, n) wg.Done() // 减少一个计数 } } type worker struct { in chan int wg *sync.WaitGroup } func createWorker(id int, wg *sync.WaitGroup) worker { w := worker{ in: make(chan int), wg: wg, } go doWorker(id, w.in, wg) return w } func chanDemo() { var wg sync.WaitGroup var workers [10]worker for i:=0; i<10; i++ { workers[i] = createWorker(i, &wg) } for i, worker := range workers { wg.Add(1) // 添加一个计数 worker.in <- ‘a‘ + i } wg.Wait() // 阻塞,等待所有任务完成 } func main() { chanDemo() }
// A Mutex is a mutual exclusion lock.// The zero value for a Mutex is an unlocked mutex.//// A Mutex must not be copied after first use.type Mutex struct { state int32 sema uint32}
示例代码:
package main import ( "sync" "fmt" ) var x = 0 func increment(wg *sync.WaitGroup, mu *sync.Mutex) { mu.Lock() x++ mu.Unlock() wg.Done() } func main() { var wg sync.WaitGroup var mu sync.Mutex for i := 0; i < 1000; i++ { wg.Add(1) go increment(&wg, &mu) } wg.Wait() fmt.Println("final value of x", x) }
原文地址:https://www.cnblogs.com/vincenshen/p/9382371.html
时间: 2024-11-11 01:14:08