remove/return semaphore

[kapil1089thekin]

why these code in the second paragraph does not remove or return the semaphore?
Each time I have to remove them using ipcs system call from the prompt, but I want to remove them from the program. Thanks in advance.

 
     int a;
        if((a = semget(IPC_PRIVATE,1,0777|IPC_CREAT))==-1) {              // get semaphore a
                perror("\nFailed to create semaphore.");
                exit(0);
        }

        if((semctl(a,0,IPC_RMID,0))==-1) {                                // Return semaphore a 
                perror("\nCan't RPC_RMID.");                                             
                exit(0);                                                                                
         }