go atomic swappointer

swap.go

package main

import (
	"fmt"
	"sync/atomic"
	"unsafe"
)

type thing struct {
	name string
}

type tracker struct {
	pointer *thing
}

func main() {
	xx := &thing{name: "ORIGINAL THING"}
	yy := &thing{name: "ANOTHER THING"}

	fmt.Printf("address for original %d, address for new %d\n", &xx, &yy)

	t := &tracker{pointer: xx}

	fmt.Printf("before: mem address %d, value %s\n", &t.pointer, t.pointer.name)
	atomic.SwapPointer((*unsafe.Pointer)((unsafe.Pointer)(&t.pointer)), unsafe.Pointer(yy))
	fmt.Printf("after: mem address %d, value %s\n", &t.pointer, t.pointer.name)
}