#include <iostream>
#include <sys/types.h>
#include <sys/sem.h>
#include <sys/ipc.h>
#include <errno.h>
#include "err.h"

using namespace std;

int main ()
{
  struct sembuf sembuf[10], *sops;
  int retrn, flags, sem_num, semid, op;
  unsigned i, nsops;

  sops = sembuf;

  cout << "Enter the semid of the semaphore set = ";
  cin >> semid ;
  cout << endl << "semid = " << semid << endl;

  cout << "Enter the number of operations on this set = ";
  cin >> nsops;
  cout << endl;

  for ( i = 0; i < nsops; i++, sops++) {
    cout << "Enter semaphore number = ";
    cin >> sem_num ;
    cout << endl;
    sops->sem_num = sem_num;

    cout << "Enter the operation = ";
    cin >> op;
    cout << endl;
    sops->sem_op = op;
    cout << "sem_num = " << sops->sem_num << " sem_op = " << sops->sem_op << endl;

    cout << "Flags:" << endl;
    cout << " 0 ---> No flags " << endl;
    cout << " 1 ---> IPC_NOWAIT " << endl;
    cout << " 2 ---> SEM_UNDO " << endl;
    cout << " 3 ---> IPC_NOWAIT and SEM_UNDO " << endl;
    cout << "flag = ";
    cin >> flags;
    cout << endl;
    switch ( flags ) {
      case 0:
        sops->sem_flg = 0;
	break;
      case 1:
	sops->sem_flg = IPC_NOWAIT;
	break;
      case 2:
	sops->sem_flg = SEM_UNDO;
	break;
      case 3:
	sops->sem_flg = SEM_UNDO | IPC_NOWAIT;
	break;
    }
    cout << "Flags = " << sops->sem_flg << endl;
  } /* for */

  sops = sembuf;

  /*************************************************************/

  retrn = semop( semid, sops, nsops );
  
  /*************************************************************/

  if ( retrn == -1 ) syserr("semop");
  
  cout << "Semop was successful!" << endl;
  cout << "Semop return ---->" << retrn << endl;
  return 0;
}