Wait Group

A sync.WaitGroup lets main wait until a goroutine calls Done.

wait_group.go

package main

import (
	"fmt"
	"sync"
)

func main() {
	var base = 
	var wg sync.WaitGroup
	results := make(chan int, 1)

	wg.Add(1)
	go func() {
		defer wg.Done()
		results <- base * 2
	}()

	wg.Wait()
	value := <-results
	fmt.Println("base=", base)
	fmt.Println("value=", value)
	fmt.Println("complete=", true)
}

package main

import (
	"fmt"
	"sync"
)

func main() {
	var base = 
	var wg sync.WaitGroup
	results := make(chan int, 1)

	wg.Add(1)
	go func() {
		defer wg.Done()
		results <- base * 2
	}()

	wg.Wait()
	value := <-results
	fmt.Println("base=", base)
	fmt.Println("value=", value)
	fmt.Println("complete=", true)
}

package main

import (
	"fmt"
	"sync"
)

func main() {
	var base = 
	var wg sync.WaitGroup
	results := make(chan int, 1)

	wg.Add(1)
	go func() {
		defer wg.Done()
		results <- base * 2
	}()

	wg.Wait()
	value := <-results
	fmt.Println("base=", base)
	fmt.Println("value=", value)
	fmt.Println("complete=", true)
}

wait group A wait group counts active tasks so code can wait for them to finish before reading final results.