Homework & Coursework Questions

  #include <stdio.h>
  #include <unistd.h>
  #include <fcntl.h>
  #include <stdlib.h>
  #include <string.h>
  #include <sys/types.h>
  #include <sys/stat.h>
  #include <sys/ipc.h>
  #include <sys/sem.h>
  #define PUB7645 "./PubFile"
  union semun {
     int val;
     struct semid_ds *buf;
     ushort *array;
  };
  int 
  main() {
     int i=0, intValue, semID;
     key_t key;
     FILE *fptr;
      union semun arg;
      static ushort startVal[2] = {1, 0};
      static struct sembuf acquire = {0, -1, SEM_UNDO},
                           release = {1, 1, SEM_UNDO};
     key = ftok(".", 's');
     if ((semID = semget(key, 2, IPC_CREAT | 0666)) == -1) {
                    perror("Sem Creation:");
                exit(2);
     }
     arg.array = startVal;
     if (semctl(semID, 2, SETALL, arg) == -1 ) {
                     perror("semctl: SETALL");
                 exit(3);
     }
  for( ; ; ) {
        srand(getpid()+i);
        intValue =rand()*49/RAND_MAX + 1;
        if (semop(semID, &acquire, 1) == -1) {
                                      perror("Producer waiting");
                          exit(4);
        }
        if ((fptr = fopen(PUB7645, "w")) == NULL) {
                          perror(PUB7645);
                          exit(1);
        }fprintf(fptr, "%d\n", intValue);
        fclose(fptr);
        if (semop(semID, &release, 1) == -1) {
              perror("new");
              exit(5);
        }
        i++;
     }
  }

  #include <stdio.h>
  #include <unistd.h>
  #include <fcntl.h>
  #include <stdlib.h>
  #include <string.h>
  #include <sys/types.h>
  #include <sys/stat.h>
  #include <sys/ipc.h>
  #include <sys/sem.h>
  #define PUB7645 "./PubFile"
  union semun {
     int val;
     struct semid_ds *buf;
     ushort *array;
  };
  int  main() {
     int i=0, intValue, semID;
     key_t key;
     FILE *fptr;
                  union semun arg;
                  static struct sembuf acquire = {1, -1, SEM_UNDO},
                           release = {0, 1, SEM_UNDO};
     key = ftok(".", 's');
     if ((semID = semget(key, 2, IPC_CREAT | 0666)) == -1) {
                    perror("Sem Creation:");
               exit(2);
     }
  for(i=1; i<=5 ; i++) {
        if (semop(semID, &acquire, 1) == -1) {
                  perror(“Consumer waiting");
                      exit(4);
        }
        if ((fptr = fopen(PUB7645, "r")) == NULL) {
                          perror(PUB7645);
                          exit(1);
        }
        fscanf(fptr, "%d", &intValue);
        fclose(fptr);
      if (semop(semID, &release, 1) == -1) {
                    perror(“Release");
                    exit(4);
        }
        printf("%d\t", intValue);
     }
     printf("\nI am process %d. I got five numbers ", getpid());
     printf("from a producer as above.\n");
  }