Handle EOF errors gracefully in Go programs

Handle EOF errors gracefully in Go: Detect EOF errors: Use the io.EOF constant to represent EOF errors. Handle EOF gracefully: close file or connection, return sentinel value, log error.

Handle EOF errors gracefully in Go programs

When processing input/output operations such as files and network connections, encounter EOF (end of file) errors are inevitable. The Go language provides elegant and concise ways to handle these errors, ensuring program robustness.

Detecting EOF errors

EOF errors are usually represented by the io.EOF constant. To detect EOF errors, you can use the following code:

func main() {
    f, err := os.Open("input.txt")
    if err != nil {
        // 处理其他错误
    }

    b := make([]byte, 1024)
    _, err = f.Read(b)
    if err == io.EOF {
        // 到达文件结尾
        fmt.Println("EOF encountered")
    } else if err != nil {
        // 处理其他错误
    }
}

Handle EOF gracefully

After detecting an EOF error, the application can take appropriate steps to handle it gracefully :

• Close the file or connection: If the input source is no longer needed, be sure to close the file handle or release the network connection to free up resources.

  f.Close()

• Return sentinel value: Sentinel values ​​(such as nil or special errors) can be used to represent EOF so that the caller can Take different actions.

  func readLine(f *os.File) (string, error) {
    b := make([]byte, 1024)
    n, err := f.Read(b)
    if err == io.EOF {
        return "", nil
    }
    return string(b[:n]), err
  }

• Logging errors: If the EOF error is unexpected or needs to be traced, you can use a logging tool to log the error.

  log.Printf("EOF encountered while reading file: %v", err)

Practical case

The following is a practical example of handling EOF errors:

func main() {
    f, err := os.Open("input.txt")
    if err != nil {
        log.Fatal(err)
    }
    defer f.Close()

    for {
        line, err := readLine(f)
        if err == nil {
            fmt.Println(line)
        } else if err == io.EOF {
            break
        } else {
            log.Printf("Error reading line: %v", err)
        }
    }
}

This code opens a file and read its contents line by line. When the end of file is reached, it gracefully stops reading by detecting an EOF error and exiting the loop.

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