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关于对消息队列，共享内存，信号量的具体介绍

mySemSercer.c

#include
   
    #include 
    
     #include 
     
      #include 
      
       #include 
       
        #include
        
         #include 
         
          struct msgbuf { long mtype; /* message type, must be > 0 */ char mtext; /* message data */};union semun { int val; /* Value for SETVAL */ struct semid_ds *buf; /* Buffer for IPC_STAT, IPC_SET */ unsigned short *array; /* Array for GETALL, SETALL */ struct seminfo *__buf; /* Buffer for IPC_INFO (Linux-specific) */};void pGet(int sem_id){ struct sembuf sops; sops.sem_num = 0; sops.sem_op =-1; sops.sem_flg = SEM_UNDO; if(semop(sem_id,&sops,1) == -1){ printf("pGet failed!!\n"); exit(-1); }}void vPut(int sem_id){ struct sembuf sops; sops.sem_num = 0; sops.sem_op = 1; sops.sem_flg = SEM_UNDO; if(semop(sem_id,&sops,1) ==-1){ printf("vPut failed!!\n"); exit(-1); }}//目的： 通过消息队列来实现进程间的通讯，在进程到消息来访问共享内存，并且是通过信号量来控制int main (){ int shm_id,msg_id,sem_id,i; struct msgbuf readBuf; char *shmaddr; key_t key; if((key = ftok(".",1)) < 0){ printf("ftok error\n"); exit(-1); } //1.创建共享内存 if((shm_id = shmget(key,1024*4, IPC_CREAT|0666)) == -1){ printf("shmget error\n"); exit(-1); } //2.连接共享内存 shmaddr = shmat(shm_id,0,0); if(shmaddr < 0){ printf("shmat error\n"); exit(-1); } //3.创建消息队列 if((msg_id = msgget(key,IPC_CREAT|0777)) == -1){ printf("msgget error\n"); exit(-1); } //4.创新信号量 if((sem_id = semget(key,1,IPC_CREAT|0666)) == -1){ printf("semget errot\n"); exit(-1); } //5. 初始化信号量 union semun initsem; initsem.val = 0; //刚刚开始是没有锁的 if(semctl(sem_id,0,SETVAL,initsem) == -1){ printf("initsemctl error\n"); return -1; } while(1) { msgrcv(msg_id,&readBuf,sizeof(readBuf.mtext),888,0); if(readBuf.mtext == 'q'){ printf("red from que: %c\n",readBuf.mtext); break; } else if(readBuf.mtext == 'r'){ pGet(sem_id); printf("red from que: %c\n",readBuf.mtext); printf("shmat data:%s\n",shmaddr); //输出共享内存中的数据 vPut(sem_id); } } printf("quit\n"); shmdt(shmaddr);// 断开与共享内存的连接 shmctl(shm_id,IPC_RMID,NULL); msgctl(msg_id,IPC_RMID,NULL); semctl(sem_id,0,IPC_RMID); return 0;}
         
        
       
      
     
    
   

mySemClient.c

#include
   
    #include 
    
     #include 
     
      #include
      
       #include 
       
        #include
        
         #include
         
          struct msgbuf { long mtype; /* message type, must be > 0 */ char mtext; /* message data */};void pGet(int sem_id){ struct sembuf sops; sops.sem_num = 0; sops.sem_op = -1; sops.sem_flg = SEM_UNDO; if(semop(sem_id,&sops,1) == -1){ printf("pGet failed!!\n"); exit(-1); }}void vPut(int sem_id){ struct sembuf sops; sops.sem_num = 0; sops.sem_op = 1; sops.sem_flg = SEM_UNDO; if(semop(sem_id,&sops,1) ==-1){ printf("vPut failed!!\n"); exit(-1); }}int main(){ int shm_id,msg_id,sem_id,i=1; char *shmaddr; char data; key_t key; if((key = ftok(".",1)) == -1){ printf("ftok error\n"); exit(-1); } //1.获取共享内存 if((shm_id =shmget(key,1024*4,0)) == -1){ printf("shmget error\n"); exit(-1); } //2.连接共享内存 shmaddr = shmat(shm_id, 0, 0); if(shmaddr < 0){ printf("shamt error\n"); exit(-1); } //3.获取消息队列 if((msg_id = msgget(key,0)) == -1){ printf("msgget error\n"); exit(-1); } //4.获取信号量 if((sem_id = semget(key,1,0)) ==-1){ printf("semget error\n"); exit(-1); } printf("---------send data---------\n"); printf("---------------------------\n"); struct msgbuf buf; while(i){ printf("please intput:\n"); //gets(data); scanf("%c",&data); getchar(); switch(data){ case'w': pGet(sem_id); printf("data=%c\n",data); buf.mtype = 888; buf.mtext = 'r'; printf("intput shmaddr:\n"); scanf("%s",shmaddr);//向共享内存写入数据 getchar(); msgsnd(msg_id,&buf,sizeof(buf.mtext),0); vPut(sem_id); break; case'q': pGet(sem_id); printf("send quit\n"); buf.mtype = 888; buf.mtext = 'q'; msgsnd(msg_id,&buf,sizeof(buf.mtext),0); i = 0; vPut(sem_id); break; case's': pGet(sem_id); printf("s,success\n"); break; case'p': vPut(sem_id); printf("p,success\n"); break; } } shmdt(shmaddr); return 0;}