How to get memory size of variable in Go?

Question

I am curious about the memory cost of map and slice, so I wrote a program to compare the sizes. I get the memory size by unsafe.Sizeof(s)

Answer 1

This incurs some marshaling overhead but I've found it's the simplest way during runtime to get the size of a value in go. For my needs the marshaling overhead wasn't a big issue so I went this route.

func getRealSizeOf(v interface{}) (int, error) {
    b := new(bytes.Buffer)
    if err := gob.NewEncoder(b).Encode(v); err != nil {
        return 0, err
    }
    return b.Len(), nil
}