单例模式

package singleton

import (
    "fmt"
)

type Singleton interface {
    PrintSome()
}

type singleone struct {
    v int
}

var g_singleone *singleone

func GetInstance(v int) Singleton {
    if g_singleone == nil {
        g_singleone = &singleone{v}
    }
    return g_singleone
}

func (s *singleone) PrintSome() {
    fmt.Println("singleton value is", s.v)
}