补丁标准包

Question

I want to replace some function from standard Go library (os.Exit specifically). Can I do that? I tried:

myExitValue := reflect.ValueOf(func() {
    fmt.Println("exiting")
})
reflect.ValueOf(os.Exit).Set(myExitValue)

But it panics: reflect: reflect.Value.Set using unaddressable value

Answer 1

Thanks to mkopriva.

package main

import (
    "fmt"
    "os"

    "github.com/bouk/monkey"
)

func myExit(code int) {
    _ = code
    fmt.Println(`I think you shouldn't exit.`)
}

func init() {
    monkey.Patch(os.Exit, myExit)
}

func main() {
    os.Exit(1)
    fmt.Println(`But why?`)
}