> For the complete documentation index, see [llms.txt](https://rafli-ramadhan.gitbook.io/golang-example-code-by-topic/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://rafli-ramadhan.gitbook.io/golang-example-code-by-topic/golang/goroutine/mutex-mutual-exclusion.md).

# Mutex (Mutual Exclusion)

Mutex -> digunakan untuk mengatasi race condition -> locking dan unlocking

Dimana ketika kita melakukan locking terhadap mutex, maka tidak ada yang bisa melakukan locking lagi sampai kita melakukan unlock. 

Jika ada beberapa goroutine melakukan lock terhadap Mutex, maka hanya 1 goroutine yang dieksekusi, setelah goroutine tersebut melakukan unlock, baru goroutine selanjutnya melakukan lock lagi.

Kekurangan -> ada kemungkinan beberapa go routine saling menggu untuk melakukan lock -> bisa menimbulkan deadlock.

```go
package main
 
import (
    "fmt"
    "sync"
)

var wg sync.WaitGroup
var m sync.Mutex

func f(v *int, wg *sync.WaitGroup) {
    m.Lock()
    *v++
    m.Unlock()
    wg.Done()
}
 
func main() {
    var v int = 0
 
    for i := 0; i < 1000; i++ {
        wg.Add(1)
        go f(&v, &wg)
    }
 
    wg.Wait()
    fmt.Println("Finished", v)
}
```

```
Finished 1000
```

```go
package main
 
import (
    "fmt"
    "sync"
)

var wg sync.WaitGroup
var m sync.Mutex

func f(v *int, wg *sync.WaitGroup) {
    m.Lock()
    *v++
    m.Unlock()
    wg.Done()
}
 
func main() {
    var v int = 0
 
    for i := 0; i < 10000; i++ {
        wg.Add(1)
        go f(&v, &wg)
    }
 
    wg.Wait()
    fmt.Println("Finished", v)
}
```

```
Finished 10000
```

```go
package main
 
import (
    "fmt"
    "sync"
)

var wg sync.WaitGroup
var m sync.Mutex
 
func main() {
    var v int = 0
 
    for i := 0; i < 10000; i++ {
        wg.Add(1)
        go func() {
            m.Lock()
            v++
            m.Unlock()
            wg.Done()
        }()
    }
    
    wg.Wait()
    fmt.Println("Finished", v)
}
```

```
Finished 10000
```