bad file descriptor

以下代码在进行文件写入时，报了一个panic: write defer-file.txt: bad file descriptor错误

func writeString(){
	var f *os.File
	var err error
	if checkFileIsExist(path){
		f,err = os.OpenFile(path,os.O_APPEND,0666)
		fmt.Println("文件存在")
	}else{
		f,err = os.Create(path)
		fmt.Println("文件不存在")
	}
	check(err)
	n,err := io.WriteString(f,content)
	check(err)
	fmt.Printf("write %d bytes\n",n)
}

解决办法：OpenFile的flag添加一个os.O_WRONLY   flag

f,err = os.OpenFile(path,os.O_APPEND|os.O_WRONLY,0666)

参考： https://stackoverflow.com/questions/33851692/golang-bad-file-descriptor