sender.c------
#include<stdio.h>#include<stdlib.h>#include<sys/ipc.h>#include<sys/types.h>#include<sys/shm.h>#include<string.h>#include<sys/sem.h>
#define SEMNUMBER 1
int main(){ key_t key; int shmflag; int shmid; int shmsize = 27; char *shmaddr; char *shmbuf; char c; int semflag; int semid; short semaphore[SEMNUMBER]; int i; struct sembuf sembuffer[1];
if ((key = ftok( "/opt", 101)) == -1){ printf("Failed to create unique key \n"); exit(0); } shmflag = IPC_CREAT | 0666; if ((shmid = shmget(key,shmsize,shmflag)) == -1){ printf("Failed to get a message queue identifier\n"); exit(0); }
printf("....Welcome To Shared Memory IPC Mechanism\n");
if ((shmaddr = shmat(shmid, NULL, 0)) == (char *) -1){ printf("shmat failed\n"); perror("shmat:"); exit(0); }
semflag = IPC_CREAT | 0666;
if((semid = semget(key, SEMNUMBER, semflag)) == -1){ printf("Failed to get a Semaphore identifier\n"); perror("semget:"); exit(0); }
printf("Hey.... Now you are using Semaphore also\n");
for(i=0; i < SEMNUMBER; i++){ semaphore[i] = 0; }
if(( semctl(semid, 1, SETALL, semaphore)) == -1){ printf("Set semaphore control failed\n"); perror("semctl:"); exit(0); }
shmbuf = shmaddr;
for ( c = 'a'; c <= 'z' ; c++){ sembuffer[0].sem_num = 0; sembuffer[0].sem_op = 1; sembuffer[0].sem_flg = 0; if(( semop(semid, sembuffer, 1)) == -1){ printf("1.Failed in Semaphore operation\n"); perror("semop:"); exit(0); } sleep(1); *shmbuf++ = c;
sembuffer[0].sem_num = 0; sembuffer[0].sem_op = -1; sembuffer[0].sem_flg = 0; if(( semop(semid, sembuffer, 1)) == -1){ printf("2.Failed in Semaphore operation\n"); perror("semop:"); exit(0); }
}
*shmbuf = '\0';
while(*shmaddr != '*') sleep(1); return 0;}
receiver.c--------
#include<stdio.h>#include<stdlib.h>#include<string.h>#include<sys/ipc.h>#include<sys/types.h>#include<sys/shm.h>#include<signal.h>#include<sys/sem.h>
#define SEMNUMBER 1
void shmquit();
int shmid; int semid;
int main(){ int key; int shmflag; int shmsize = 27; char *shmaddr; char *shmbuf; int semflag; short semaphore[SEMNUMBER]; int i; struct sembuf sembuffer[1];
if ((key = ftok( "/opt", 101)) == -1){ printf("Failed to create unique key \n"); exit(0); }
shmflag = IPC_CREAT | 0666;
if ((shmid = shmget(key,shmsize, shmflag)) == -1){ printf("Failed to get a shared memory identifier\n"); exit(0); } printf("....Welcome To Shared Memory IPC Mechanism\n");
semflag = IPC_CREAT | 0666;
if(( semid = semget(key, SEMNUMBER, semflag)) == -1){ printf("Failed to get a Semaphore identifier\n"); exit(0); } printf("Hey now you are using semaphore also\n");
for(i=0; i<SEMNUMBER; i++){ semaphore[i] = 0; }
if(( semctl(semid, 1, SETALL, semaphore)) == -1){ printf("semaphore control Failed\n"); exit(0); }
signal(SIGINT, (void *)shmquit);
while(1){ sembuffer[0].sem_num = 0; sembuffer[0].sem_op = 1; sembuffer[0].sem_flg = 0;
if(( semop(semid, sembuffer, 1)) == -1){ printf("Failed in semaphore operation\n"); exit(0); }
if( (shmaddr = shmat(shmid, NULL, 0)) == (char *) -1){ printf("Shmat failed\n"); exit(0); } printf("%s",shmaddr); putchar('\n');
if( (shmdt(shmaddr)) == -1){ printf("Shmdt failed\n"); exit(0); } sembuffer[0].sem_num = 0; sembuffer[0].sem_op = -1; sembuffer[0].sem_flg = 0;
if(( semop(semid, sembuffer, 1)) == -1){ printf("Failed in semaphore operation\n"); exit(0); }
} *shmaddr = '*'; return 0;}void shmquit(){ signal(SIGINT, (void *)shmquit); shmctl(shmid, IPC_RMID, 0); semctl(semid,0, IPC_RMID); printf(" \nThank you for using Shared memory and semaphore .... DONE\n"); exit(0);
}
