main.go中调用 modle中的xorm 为nil

目录结构 ``` proj │ go.mod │ main.go │ go.sum │ user.db │ └─models dao.go ``` proj\models\dao.go ``` package models import ( "fmt" "github.com/go-xorm/xorm" _ "github.com/mattn/go-sqlite3" "time" ) var ( baseTimestamp time.Time x *xorm.Engine ) func CallFuncFromMoles() { fmt.Println(baseTimestamp) fmt.Println(x) } func init() { fmt.Println("models init") baseTimestamp = time.Now() fmt.Println(baseTimestamp) x, err := xorm.NewEngine("sqlite3", "user.db") fmt.Println(x, err) } ``` proj\main.go ``` package main import ( "proj/models" "fmt" ) func main(){ fmt.Println("now in main CallFuncFromMoles") models.CallFuncFromMoles() } ``` go run main.go ``` ef20 UUID:0xf4f2e0 VARBINARY:0xf4f2e0 VARCHAR:0xf4f2e0 VERSION:0xf4eea0 YEAR:0xf4f2e0] <nil> map[] {{0 0} 0 0 0 0} 0xc0000ae128} <nil> now in main CallFuncFromMoles 2021-03-17 21:09:08.1911855 +0800 CST m=+0.006000301 <nil> ``` baseTimestamp init和 CallFuncFromMoles都 有值 x 只在init 有值，CallFuncFromMoles为nil