#include<iostream>
#include<sys/wait.h>
#include<sys/types.h>
#include<sys/mman.h>
#include<unistd.h>
using namespace std;
int main(void) {
         int pagesize=getpagesize();//4KB
         int *shm;
         cout<< "page size="<< pagesize<<endl;
         shm=(int *)mmap(NULL,pagesize,PROT_READ|PROT_WRITE,MAP_SHARED|MAP_ANONYMOUS,-1,0);
         int pid=fork();
         if (pid==0) {
                  *shm=15;
                  shm++;
                  *shm=20
         } else {
              wait(NULL);
              cout<< *shm <<endl;
              shm++;
              cout<< *shm<<endl;
         }
         return 0;
}