Go语言中的sync包同步原语最新详解

package main
import (
	"fmt"
	"sync"
	"time"
)
func worker(id int, wg *sync.WaitGroup) {
	defer wg.Done() // Decrement the Wait Group counter when done
	fmt.Printf("Worker %d is working\n", id)
	time.Sleep(time.Second)
	fmt.Printf("Worker %d has finished\n", id)
}
func main() {
	var wg sync.WaitGroup
	for i := 1; i <= 3; i++ {
		wg.Add(1) // Increment the Wait Group counter for each Goroutine
		go worker(i, &wg)
	}
	wg.Wait() // Wait for all Goroutines to finish
	fmt.Println("All workers have finished.")
}

package main
import (
	"fmt"
	"sync"
	"time"
)
var (
	data        int
	dataMutex   sync.RWMutex
)
func readData() int {
	dataMutex.RLock() // Read Lock
	defer dataMutex.RUnlock()
	return data
}
func writeData(value int) {
	dataMutex.Lock() // Write Lock
	defer dataMutex.Unlock()
	data = value
}
func main() {
	// Read data concurrently
	for i := 1; i <= 5; i++ {
		go func() {
			fmt.Println("Read Data:", readData())
		}()
	}
	// Write data
	writeData(42)
	time.Sleep(time.Second)
}

package main
import (
	"fmt"
	"sync"
	"time"
)
var (
	conditionMutex sync.Mutex
	condition      *sync.Cond
	isReady        bool
)
func waitForCondition() {
	conditionMutex.Lock()
	defer conditionMutex.Unlock()
	for !isReady {
		fmt.Println("Waiting for the condition...")
		condition.Wait()
	}
	fmt.Println("Condition met, proceeding.")
}
func setCondition() {
	time.Sleep(2 * time.Second)
	conditionMutex.Lock()
	isReady = true
	condition.Signal() // Signal one waiting Goroutine
	conditionMutex.Unlock()
}
func main() {
	condition = sync.NewCond(&conditionMutex)
	go waitForCondition()
	go setCondition()
	time.Sleep(5 * time.Second)
}

package main
import (
	"fmt"
	"sync"
	"sync/atomic"
	"time"
)
var (
	counter int32
	wg      sync.WaitGroup
)
func incrementCounter() {
	defer wg.Done()
	for i := 0; i < 100000; i++ {
		atomic.AddInt32(&counter, 1)
	}
}
func main() {
	wg.Add(2)
	go incrementCounter()
	go incrementCounter()
	wg.Wait()
	fmt.Println("Counter:", atomic.LoadInt32(&counter))
}