How is error handling implemented in golang functions?

Function error handling in the Go language is implemented by returning an error of the error interface type. 1. The Error() method of the built-in error interface type returns a description string of the error. 2. Handle the error by comparing if err != nil to see if the error is empty. 3. Error handling is suitable for practical applications such as file reading and database query.

Implementation of function error handling in Go language

In Go language, a function can return an error Interface type error indicates that the execution of the function failed. Error handling is implemented by calling the Error() method of the built-in error interface type, which returns a string describing the error.

Code example:

The following is a simple example of handling errors:

func divide(a, b int) (int, error) {
    if b == 0 {
        return 0, errors.New("division by zero") // 返回错误
    }
    return a / b, nil // 返回结果和 nil（无错误）
}

func main() {
    result, err := divide(10, 2)
    if err != nil {
        fmt.Println("Error:", err.Error()) // 处理错误
    } else {
        fmt.Printf("Result: %d\n", result)
    }
}

Practical case:

Read file:

func readFile(filename string) ([]byte, error) {
    data, err := ioutil.ReadFile(filename)
    if err != nil {
        return nil, errors.New("could not read file: " + filename)
    }
    return data, nil
}

Database query:

func queryDatabase(query string) (*sql.Rows, error) {
    rows, err := db.Query(query)
    if err != nil {
        return nil, errors.New("could not execute query: " + query)
    }
    return rows, nil
}

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