go defer 相关知识点

package main

type Foo struct {
    v int
}

func NewFoo(n *int) Foo {
    println("NewFoo",*n)
    return Foo{}
}

func (Foo) Bar(n *int) {
    println("bar",*n)
}

func main() {
    var x = 1
    var p = &x

    println("1---",*p)
    defer NewFoo(p).Bar(p)
    println("2---",*p)

    x = 2
    p = new(int)
    println("start---",*p)
    NewFoo(p)
    println("end--",*p)
}

result

1--- 1
NewFoo 1
2--- 1
start--- 0
NewFoo 0
end-- 0
bar 2