the-way-to-go_ZH_CN/eBook/examples/chapter_6/defer_dbconn.go

// defer_dbconn.go
package main

import "fmt"

func main() {
    doDBOperations()
}

func connectToDB () {
    fmt.Println( "ok, connected to db" )
}

func disconnectFromDB () {
    fmt.Println( "ok, disconnected from db" )
}

func doDBOperations() {
     connectToDB()
     fmt.Println("Defering the database disconnect.")
     defer disconnectFromDB() //function called here with defer
     fmt.Println("Doing some DB operations ...")
     fmt.Println("Oops! some crash or network error ...")
     fmt.Println("Returning from function here!")
     return //terminate the program
     // deferred function executed here just before actually returning, even if there is a return or abnormal termination before
}
/* Output:
ok, connected to db
Defering the database disconnect.
Doing some DB operations ...
Oops! some crash or network error ...
Returning from function here!
ok, disconnected from db
*/