Go defer的實現(xiàn)機(jī)制到底怎么回事？？？

太感謝@勤奮的小小塵，完全解決了心中的疑慮，果然如此。我這的VPN用不了了，某度又找不準(zhǔn)想要的。真是千恩萬謝

官網(wǎng)blog 有對defer, panic, and recover的詳細(xì)說法，不知道你能不能打開

https://blog.golang.org/defer...

摘錄一下
A defer statement pushes a function call onto a list. The list of saved calls is executed after the surrounding function returns. Defer is commonly used to simplify functions that perform various clean-up actions.

The behavior of defer statements is straightforward and predictable. There are three simple rules:

1. A deferred function's arguments are evaluated when the defer statement is evaluated.

In this example, the expression "i" is evaluated when the Println call is deferred. The deferred call will print "0" after the function returns.

func a() {
    i := 0
    defer fmt.Println(i)
    i++
    return
}

2. Deferred function calls are executed in Last In First Out order after the surrounding function returns.

This function prints "3210":

func b() {
    for i := 0; i < 4; i++ {
        defer fmt.Print(i)
    }
}

3. Deferred functions may read and assign to the returning function's named return values.

In this example, a deferred function increments the return value i after the surrounding function returns. Thus, this function returns 2:

func c() (i int) {
    defer func() { i++ }()
    return 1
}

希望你能理解