标签：time var copy class code demo each block nis
// 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) }
Go sync.WaitGroup 等待Goroutine执行完成
标签：time var copy class code demo each block nis
原文地址：https://www.cnblogs.com/vincenshen/p/9382371.html
