golang json中的指针解组

Question

I'm trying to unmarshal a web service response using the below command and it works fine.

bodyBytes, _ := ioutil.ReadAll(response.Body)
bodyString := string(bodyBytes)
err = json.Unmarshal([]byte(bodyString), &output)
fmt.Println(&output)

When I use the pointer variable '&output' it works fine ie; the outputs are displayed properly.

but when I try to use the variable directly without &(ampersand), the outputs do not look good.

bodyBytes, _ := ioutil.ReadAll(response.Body)
bodyString := string(bodyBytes)
err = json.Unmarshal([]byte(bodyString), output)
fmt.Println(output)

What is the difference between these 2 variable - pointer vs normal variable while unmarshalling?

var output core.ApiData

The output is a type struct to match the apidata output.

Answer 1

It is because the Unmarshal function takes the output struct and populates it with the data. If you do not pass a pointer, it will take a copy of your struct and fill it, after which you don't have access to it any more. If you pass a pointer, the output struct behind the pointer will be populated and remain available.