Error()函数的返回值类型和返回结果的处理方式

The Error() function in Go language returns an error value. The error value is an implementation of the error interface which has a method Error() that returns a string describing the error.

The return type of the Error() function is error. This means that any function that returns an error can return a value that implements the error interface.

To handle the returned error, we can use a typical idiomatic Go approach of using an if statement with a short-circuiting conditional statement. This allows us to check if the error value is nil, indicating that no error occurred, or if an error occurred and to handle it appropriately.

Here is an example to demonstrate the usage of the Error() function and handling the returned error:

package main

import (
	"errors"
	"fmt"
)

func divide(a, b int) (int, error) {
	if b == 0 {
		return 0, errors.New("division by zero")
	}
	return a / b, nil
}

func main() {
	result, err := divide(10, 2)
	if err != nil {
		fmt.Println("Error:", err)
	} else {
		fmt.Println("Result:", result)
	}

	result, err = divide(10, 0)
	if err != nil {
		fmt.Println("Error:", err)
	} else {
		fmt.Println("Result:", result)
	}
}

In the above code, we have a divide() function that takes two integers a and b as input and returns the result of dividing a by b. If the division is not possible (i.e., b is zero), it returns an error value with a string describing the error.

In the main() function, we call the divide() function twice. The first call with 10 and 2 as arguments will successfully divide and return the result 5. The second call with 10 and 0 as arguments will return an error value because division by zero is not possible.

We use an if statement with a short-circuiting conditional statement to check if the error value returned by the divide() function is nil or not. If it is not nil, it means an error occurred, and we print the error message. If it is nil, it means no error occurred, and we print the result.

The output of the above code will be:

Result: 5
Error: division by zero

As we can see, the Error() function returns a string describing the error, and we can handle the error by checking if the returned error value is nil or not. This allows us to handle errors and provide appropriate feedback or take necessary actions in our code.