Wrapping your mind around Go's double pointer dereference

pointers.go

package main

import "fmt"

type example struct {
	a string
	b string
}

// run me on https://play.golang.org/p/xxbFzUHBM6j

func main() {
	// A pointer type denotes the set of all pointers to variables of a given type, called the base type of the pointer. The value of an uninitialized pointer is nil.
	// PointerType = "*" BaseType .
	// BaseType    = Type .

	a := &example{a: "foo", b: "bar"}
	// fmt.Println(**a) // this results in a runtime error because a is not a pointer value.
	b := &a
	fmt.Printf("%T\n", b)
	fmt.Printf("a:\t%p\nb:\t%p\n*b:\t%p\n**b:\t%v", a, b, *b, **b) // notice how *b "points" to the same memory address as a.
}