#include <semaphore.h>
#include <stdio.h>
#include <errno.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <sys/mman.h>
#define SIZE 20
//syncro6.c
int main(int argc, char **argv)
{
  int fd, i, val, pid,*ptr;
  sem_t mutex;
  sem_t* pmutex;
  ptr = mmap(0, sizeof(int)*SIZE+sizeof(sem_t*), 
			 PROT_READ|PROT_WRITE,MAP_ANONYMOUS|MAP_SHARED, -1, 0);

  pmutex=(sem_t*)(ptr+sizeof(int)*SIZE);
  sem_init(pmutex,1,1);


  pid=fork();
  if (pid == 0) { 
    for (i = 0; i < SIZE; i++) { 
		sem_wait(pmutex); 
  	val=(*ptr)++;
	printf("figlio: %d\n", val); 
		sem_post(pmutex); 
    }
    exit(0);
  }
  else{
     for (i = 0; i < SIZE; i++) { 
		sem_wait(pmutex);  
	val=(*ptr)++;
	usleep(1e2); 
	printf("padre:  %d\n", val);   
		sem_post(pmutex); 
     }
   }
   wait();
   return(0);
}