dereferencing pointer to struct creates copy?

gistfile1.cpp

#include <iostream>
using namespace std;

typedef struct Something
{
   int number;
} Something, *PSomething;

#define UPDATE_SOMETHING(something, n) (something).number = n;

void modifySomething(PSomething pSomething) {
  // 1. 
	pSomething->number = 99;
	// 2. 
	(*pSomething).number = 99;
  /* 3.
	Something s = *pSomething;
  UPDATE_SOMETHING(s, 9);
  cout<<"addr: "<<&s<<endl;
  cout<<"  .number: "<<s.number<<endl;
  */
}

int main(int argc, char *argv[]) {
  Something s1 = {0};
  modifySomething(&s1);
  cout<<"addr: "<<&s1<<endl;
  cout<<"  .number: "<<s1.number<<endl;
  char line[80];
  cin>>line;
}