戈朗的原子变量
在 Go 语言中，使用原子变量来控制状态。这里，必须使用“同步/原子”包来使用这些变量。此外，它还防止了允许两个或更多的戈鲁蒂尼访问相同来源的比赛条件。原子计数器有几种类型。用 go 语言管理状态的主要手段是通过渠道进行沟通。
例 1:
// Golang program to illustrate the usage of
// atomic variable
// Including main package
package main
// Importing sync/atomic, math/rand,
// fmt, sync, and time
import (
"fmt"
"math/rand"
"sync"
"sync/atomic"
"time"
)
// Using sync.WaitGroup in order to
// wait for a collection of
// goroutines to finish
var waittime sync.WaitGroup
// Declaring atomic variable
var atmvar int32
// Defining increment function
func hike(S string) {
// For loop
for i := 1; i < 7; i++ {
// Calling sleep method with its duration
// and also calling rand.Intn method
time.Sleep(time.Duration((rand.Intn(5))) * time.Millisecond)
// Calling AddInt32 method with its
// parameter
atomic.AddInt32(&atmvar, 1)
// Prints output
fmt.Println(S, i, "count ->", atmvar)
}
// Wait completed
waittime.Done()
}
// Main function
func main() {
// Calling Add method w.r.to
// waittime variable
waittime.Add(2)
// Calling hike method with
// values
go hike("cat: ")
go hike("dog: ")
// Calling wait method
waittime.Wait()
// Prints the value of last count
fmt.Println("The value of last count is :", atmvar)
}
输出:
dog: 1 count -> 1
cat: 1 count -> 2
dog: 2 count -> 3
dog: 3 count -> 4
cat: 2 count -> 5
cat: 3 count -> 6
cat: 4 count -> 7
cat: 5 count -> 8
cat: 6 count -> 9
dog: 4 count -> 10
dog: 5 count -> 11
dog: 6 count -> 12
The value of last count is : 12
在上面的方法中，原子变量的类型是 int32。在这里，兰特。Intn()方法用于打印随机整数，直到循环停止。之后，使用 AddInt32 方法，将原子变量与另一个 Int32 数相加，然后在计数中返回。
例 2:
// Golang program to illustrate the usage of
// AfterFunc() function
// Including main package
package main
// Importing sync/atomic, fmt,
// and sync
import (
"fmt"
"sync"
"sync/atomic"
)
// Calling main
func main() {
// Declaring atomic variable
var atmvar uint32
// Using sync.WaitGroup in order to
// wait for a collection of
// goroutines to finish
var wait sync.WaitGroup
// For loop
for i := 0; i < 30; i += 2 {
// Calling Add method
wait.Add(1)
// Calling AddUint32 method under
// go function
go func() {
atomic.AddUint32(&atmvar, 2)
// Wait completed
wait.Done()
}()
}
// Calling wait method
wait.Wait()
// Prints atomic variables value
fmt.Println("atmvar:", atmvar)
}
输出:
atmvar: 30
在上面的方法中，原子变量是 uint32 类型。这里，在 for 循环下使用 AddUint32()方法，该方法添加其参数，直到循环停止，然后返回原子变量的值。
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