go - unsafe.SizeOf() says any string takes 16 bytes, but how?

Question

This question already has an answer here: question from:https://stackoverflow.com/questions/65878177/unsafe-sizeof-says-any-string-takes-16-bytes-but-how

Answer 1

Strings in Go are represented by reflect.StringHeader containing a pointer to actual string data and a length of string:

type StringHeader struct {
        Data uintptr
        Len  int
}

unsafe.Sizeof(s) will only return the size of StringHeader struct but not the pointed data itself. So (in your example) it will be sum of 8 bytes for Data and 8 bytes for Len making it 16 bytes.