How to use sync package

Stdlib
2026-04-17T12:05:42+00:00
The sync package provides basic synchronization primitives like WaitGroup, Mutex, and Once to coordinate goroutines safely.

The sync package provides basic synchronization primitives like WaitGroup, Mutex, and Once to coordinate goroutines. Use sync.WaitGroup to wait for a collection of goroutines to finish, sync.Mutex to protect shared data, or sync.Once to ensure a function runs exactly once.

package main

import (
	"fmt"
	"sync"
)

func main() {
	var wg sync.WaitGroup
	wg.Add(2)

	go func() {
		defer wg.Done()
		fmt.Println("Goroutine 1")
	}()

	go func() {
		defer wg.Done()
		fmt.Println("Goroutine 2")
	}()

	wg.Wait()
	fmt.Println("Done")
}