fifo_write.c ![实验楼](https://dn-simplecloud.shiyanlou.com/4240301496835600246-wm) fifo_read,c ![实验楼](https://dn-simplecloud.shiyanlou.com/4240301496835677748-wm) msgsnd.c ![实验楼](https://dn-simplecloud.shiyanlou.com/4240301496835725820-wm) msgrcv.c ![实验楼](https://dn-simplecloud.shiyanlou.com/4240301496835790342-wm) 运行结果： ![实验楼](https://dn-simplecloud.shiyanlou.com/4240301496831153308-wm) ![实验楼](https://dn-simplecloud.shiyanlou.com/4240301496833973004-wm) ##代码注释 /* fifo_write.c */ include include include include include include include define MYFIFO "/tmp/myfifo" /* 有名管道文件名*/ define MAX_BUFFER_SIZE PIPE_BUF /*定义在于 limits.h 中*/ int main(int argc, char * argv[]) /*参数为即将写入的字符串*/ {/*定义参数，以及用到的字符串*/ int fd; char buff[MAX_BUFFER_SIZE]; int nwrite; if(argc <= 1)/*判断是否有参数*/ { printf("Usage: ./fifo_write string\n"); exit(1); } /*保存输入的参数信息*/ sscanf(argv[1], "%s", buff); /* 以只写阻塞方式打开 FIFO 管道 */ fd = open(MYFIFO, O_WRONLY); /*判断通道是否打开*/ if (fd == -1) { printf("Open fifo file error\n"); exit(1); } /*向管道中写入字符串*/ if ((nwrite = write(fd, buff, MAX_BUFFER_SIZE)) > 0) /*nwrite为写入的字符串，如果大于1为成功，如果为-1为出错*/ { printf("Write '%s' to FIFO\n", buff); } close(fd); /*关闭通道*/ exit(0); } /*fifo_read.c*/ include include include include include include include define MYFIFO "/tmp/myfifo" /* 有名管道文件名*/ define MAX_BUFFER_SIZE PIPE_BUF /*定义在于 limits.h 中*/ int main() { char buff[MAX_BUFFER_SIZE]; int fd; int nread; /* 判断有名管道是否已存在，若尚未创建，则以相应的权限创建*/ if (access(MYFIFO, F_OK) == -1) /*判断文件MYFIFO文件是否存在*/ { if ((mkfifo(MYFIFO, 0666) < 0) && (errno != EEXIST)) /*判断mkfifo是否创建成功已经是否存在同名管道*/ { printf("Cannot create fifo file\n"); exit(1); } } /* 以只读阻塞方式打开有名管道 */ fd = open(MYFIFO, O_RDONLY); if (fd == -1) /*判断管道是否成功打开*/ { printf("Open fifo file error\n"); exit(1); } while (1) { memset(buff, 0, sizeof(buff));/*清空数据*/ /*nread 为读取文档的字节数，如果大于0成功，如果为-1则出错*/ if ((nread = read(fd, buff, MAX_BUFFER_SIZE)) > 0) /*读取文件描述符为 fd 的管道中字节数为MAX_BUFFER_SIZE的数据，写入 buff 指向的缓冲区*/ { printf("Read '%s' from FIFO\n", buff); } } close(fd); exit(0); } ###消息列队部分 /* msgsnd.c */ #include include #include #include #include #include #include #define BUFFER_SIZE 512 struct message { int msg_type; char msg_text[BUFFER_SIZE]; }; int main() { int qid; key_t key; struct message msg; /*根据不同的路径和关键字产生标准的 key*/ if ((key = ftok(".", 'a')) == -1) /*判断key是否生成成功*/ { perror("ftok"); exit(1); } /*创建消息队列*/ if ((qid = msgget(key, IPC_CREAT|0666)) == -1) /*判断消息列队是否创建成功*/ { perror("msgget"); exit(1); } printf("Open queue %d\n",qid); while(1) /*循环持续的将信息添加到消息列队*/ { printf("Enter some message to the queue:"); if ((fgets(msg.msg_text, BUFFER_SIZE, stdin)) == NULL) /*判断读取的是否读取到数据，如果没读取到或者出现错误返回null*/ { puts("no message"); exit(1); } msg.msg_type = getpid(); /*添加消息到消息队列*/ if ((msgsnd(qid, &msg, strlen(msg.msg_text), 0)) < 0) /*判断是否添加成功，如果添加成功则返回0，失败返回-1*/ {perror("message posted"); exit(1); } /*如果msg.msg_text前4个字符为“quit”则退出循环*/ if (strncmp(msg.msg_text, "quit", 4) == 0) {break;} } exit(0); } /* msgrcv.c */ include include include include include include include define BUFFER_SIZE 512 struct message { int msg_type; char msg_text[BUFFER_SIZE]; }; int main() { int qid; key_t key; struct message msg; /*根据不同的路径和关键字产生标准的 key*/ if ((key = ftok(".", 'a')) == -1) /*判断key是否生成成功*/ { perror("ftok"); exit(1); } /*创建消息队列*/ if ((qid = msgget(key, IPC_CREAT|0666)) == -1) /*判断消息列队是否创建成功*/ { perror("msgget"); exit(1); } printf("Open queue %d\n", qid); do { /*读取消息队列*/ memset(msg.msg_text, 0, BUFFER_SIZE); /*清空数据*/ /*取走队列ID为 qid 消息队列中*当前最早的*消息到 msg 指向的缓冲区，消息大小大小为BUFFER_SIZE*/ if (msgrcv(qid, (void*)&msg, BUFFER_SIZE, 0, 0) < 0) /*判断是否读取成功，如果读取成功则返回0，失败返回-1*/ { perror("msgrcv"); exit(1); } printf("The message from process %d : %s", msg.msg_type, msg.msg_text); } while(strncmp(msg.msg_text, "quit", 4)); /*如果msg.msg_text前4个字符为“quit”则退出循环*/ /*从系统内核中移走消息队列 */ if ((msgctl(qid, IPC_RMID, NULL)) < 0) /*判断是否成功，成功返回0，失败返回-1*/ { perror("msgctl"); exit(1); } exit(0); }

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