package main
import "fmt"

func main() {
    sl_from := []int{1, 2, 3}
    sl_to := make([]int, 10)

    n := copy(sl_to, sl_from)
    fmt.Println(sl_to)
    fmt.Printf("Copied %d elements\n", n) // n == 3

    sl3 := []int{1, 2, 3}
    sl3 = append(sl3, 4, 5, 6)
    fmt.Println(sl3)
}