How does golang return error information?

Returning error information in Go: Use the error type to represent error information. Use errors.New() to create simple error messages. Use fmt.Errorf() to create detailed error messages. Errors are caught via if err != nil and handled via fmt.Println(err).

Returning error information in Go

In Go, you can use the error type to represent error information . The following code shows how to return an error message:

func myFunc() error {
  // 出现错误时，使用 errors.New() 创建错误并返回
  return errors.New("some error occurred")
}

You can also create a more detailed error message using the fmt.Errorf() function:

func myFunc() error {
  return fmt.Errorf("some error occurred: %v", someVariable)
}

Capture and handle errors Information:

func main() {
  err := myFunc()
  if err != nil {
    // 处理错误
    fmt.Println(err)
  }
}

Practical case:

In the following example, we return an error in the function and capture it in the main function Handle it:

func readFile(filename string) error {
  file, err := os.Open(filename)
  if err != nil {
    return err
  }
  defer file.Close()
  // ...
  return nil
}

func main() {
  err := readFile("non-existent-file.txt")
  if err != nil {
    fmt.Println(err)
  }
}

This way you can handle and communicate the error gracefully to the user.

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