package main

import (
    "fmt"
    "time"
    "log"
    "os"
)

func main() {
    go func() {
        defer func() {
            i := recover()
            if i != nil {
                file, _ := os.Create("error.log")
                defer file.Close()

                logger := log.New(file, "[Error] ", log.Ldate|log.Ltime)     // [Error] 2018/07/28 17:43:23 runtime error: invalid memory address or nil pointer dereference
                logger.Println(i)

            }
        }()
        var p *int
        //p = new(int)
        *p = 1000
        fmt.Println("hello")
    }()

    time.Sleep(time.Second)
    fmt.Println("hello main")
}