25. Go - Wait Sync

Wait provides a method to prevent application from closing prematurely while using goroutines.


var wg sync.WaitGroup // creates a sync waitgroup

wg.Add() // add how many waitgroups there are. takes in an int

defer wg.Done() // finishes a waitgroup. it is deferred so will be called when function finishes.
wg.Done() // also works by itself without defer

wg.Wait() // a method that waits for the waitgroups to finish.


Example:

package main

import (
    "fmt"
    "sync"
)

var wg sync.WaitGroup

func main() {

    wg.Add(2)
    go count()
    go count()
    wg.Wait()

}

func count() {
    defer wg.Done()
    for i := 0; i < 10; i++ {
        fmt.Println(i)
    }
}

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