package main
import "fmt"
func doStuff(q interface{}) {
*q = MyStruct{2}
}
type MyStruct struct {
f1 int
}
func main() {
ms := MyStruct{1}
doStuff(&ms)
fmt.Printf("Hello, playground: %v\n", ms)
}
Is it possible to set ms through pointer q to have new value MyStruct{2}? I am getting this error invalid indirect of q (type interface {})
interface{} is not a pointer type. So, you cannot change it's underlying value.
Instead, you can modify q value and return it from the doStuff function if you really need to do so.
example:
package main
import "fmt"
func doStuff(q interface{}) interface{} {
q = &MyStruct{2}
return q
}
type MyStruct struct {
f1 int
}
func main() {
var ms interface{} = MyStruct{1}
ms = doStuff(&ms)
fmt.Printf("Hello, playground: %v\n", ms)
}
You can't using the interface{} type, since it's not a literal type you can memory address like you're attempting. An interface type describes general behavior, not a specific value.
If you use the MyStruct type directly, you can get a pointer and do what you want.
package main
import "fmt"
func doStuff(q *MyStruct) {
*q = MyStruct{2}
}
type MyStruct struct {
f1 int
}
func main() {
ms := MyStruct{1}
doStuff(&ms)
fmt.Printf("Hello, playground: %v\n", ms)
}
interface{}is not a pointer type, so you cannot use pointer indirection on it.interface{}as "any type". This is wrong.interface{}is not "any type" it is the empty interface, literallyinterface{}and a distinct fixed type like uint16, chan bool, []string or io.Reader. It is worth redoing the Tour of Go once more to become familiar with Go's types system.