Go语言中的指针语法和Viper库使用时，为什么需要传递可寻址的指针？

package setting

import (
    "github.com/spf13/viper"
    "time"
)

type Setting struct {
    vp *viper.Viper
}

func NewSetting() (*Setting, error) {
    vp := viper.New()
    vp.SetConfigName("config")
    vp.AddConfigPath("configs/")
    vp.SetConfigType("yaml")
    err := vp.ReadInConfig()
    if err != nil {
        return nil, err
    }
    return &Setting{vp: vp}, nil
}

func (s *Setting) ReadSection(k string, v interface{}) error {
    err := s.vp.UnmarshalKey(k, v) // 注意这里使用UnmarshalKey
    if err != nil {
        return err
    }
    return nil
}

package global

import "github.com/your-project/setting" // 替换成你的setting包路径

type ServerSettings struct {
    RunMode      string        `mapstructure:"runmode"`
    HTTPPort     string        `mapstructure:"httpport"`
    ReadTimeout  time.Duration `mapstructure:"readtimeout"`
    WriteTimeout time.Duration `mapstructure:"writetimeout"`
}

var ServerSetting *ServerSettings

package main

import (
    "fmt"
    "github.com/your-project/global" // 替换成你的global包路径
    "github.com/your-project/setting" // 替换成你的setting包路径
)

func main() {
    setting, err := setting.NewSetting()
    if err != nil {
        fmt.Println("Error:", err)
        return
    }

    err = setting.ReadSection("server", &global.ServerSetting) // 正确的写法
    if err != nil {
        fmt.Println("Error:", err)
        return
    }

    fmt.Println(global.ServerSetting)
}