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}
if (semop(semid, operations, 1) < 0)
{
perror("parent semop");
exit(1);
}
*parent_shm = *parent_shm + 1;
if (i%1500 == 0)
{
usleep(1); // sleep 1 us to increase window of critical section
}
operations[0].sem_num = 0;
operations[0].sem_op = 1;
operations[0].sem_flg = 0;
if (semop(semid, operations, 1) < 0)
{
perror("parent semop");
exit(1);
}
// wait for child to complete
wait(&status);
/*
* now that parent and child are done incrementing, check the
* consistency of the shm memory.
*/
printf("Child Incremented %d times, Parent %d times. SHM Value %d
\n",CHILD_INCREMENT_COUNT,PARENT_INCREMENT_COUNT,
*parent_shm);
NP Lab Manual , RNEC page: 22