#include 	<signal.h>
#include	<sys/types.h>
#include	<sys/wait.h>
#include	<stdio.h>
#include 	<stdlib.h>
void func(int signum)
{
  printf("ricevo %d\n", signum);
}
int main (void)
{
  struct sigaction new_action, old_action;

  new_action.sa_handler = func;
  sigemptyset (&new_action.sa_mask);
  new_action.sa_flags = 0;

  sigaction (SIGINT, NULL, &old_action);
  if (old_action.sa_handler != SIG_IGN)    sigaction (SIGINT, &new_action, NULL);

  sigaction (SIGHUP, NULL, &old_action);
  if (old_action.sa_handler != SIG_IGN)    sigaction (SIGHUP, &new_action, NULL);

  sigaction (SIGTERM, NULL, &old_action);
  if (old_action.sa_handler != SIG_IGN)    sigaction (SIGTERM, &new_action, NULL);

   while(1) ;
}