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
*/