golang defer语句简单解析

defer

下面举例说明了defer语句的作用：

package main

import "fmt"

func main() {

    i := 10
    defer incr(i)
    defer incr2(i)
    defer incr3(i)

}

func incr(i int){
    j := i -1
    fmt.Println(j)
}

func incr2(i int){
    j := i -2
    fmt.Println(j)
}

func incr3(i int){
    j := i -3
    fmt.Println(j)
}

输出结果:

GOROOT=C:\Go #gosetup
GOPATH=C:\Users\DELL\go #gosetup
C:\Go\bin\go.exe build -o C:\Users\DELL\AppData\Local\Temp\___go_build_cmpl_go.exe C:/Users/DELL/ActiveGo/src/spider/main/cmpl.go #gosetup
"C:\Program Files\JetBrains\GoLand 2018.3.2\bin\runnerw64.exe" C:\Users\DELL\AppData\Local\Temp\___go_build_cmpl_go.exe #gosetup
7
8
9

Process finished with exit code 0

很明显 defer语句的执行顺序是反的。这种语法给我们的资源关闭提供了很好的帮助。

比如流的关闭啊，文件的关闭啊等等。