golang 自定义错误示例

package main
import (
 "fmt"
 "time"
)
// MyError is an error implementation that includes a time and message.
type MyError struct {
 When time.Time
 What string
}
func (e MyError) Error() string {
 return fmt.Sprintf("%v: %v", e.When, e.What)
}
func oops() error {
 return MyError{
  time.Date(1989, 3, 15, 22, 30, 0, 0, time.UTC),
  "the file system has gone away",
 }
}
func Example() {
 if err := oops(); err != nil {
  fmt.Println(err)
 }
 // Output: 1989-03-15 22:30:00 +0000 UTC: the file system has gone away
}
func main() {
 Example()
}

下面的代码也来自golang源码，记录以用

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