int main(){
int pid;
int fd[2];
if(pipe(fd)<0){//父进程创建管道
perror("Fail to pipe");
exit(EXIT_FAILURE);
}
if((pid=fork())<0){
perror("Fail to fork");
exit(EXIT_FAILURE);
}else if(pid == 0){
close(fd[1]);//表示管道的方向,fd[1]用于写
child_read_pipe(fd[0]);//子进程读取管道
}else{
close(fd[0]);//fd[0]用于读
father_write_pipe(fd[1]);//父进程写入管道
}
}
#define FIFO_FILE "MYFIFO"
//有名管道server端
int main(void)
{
FILE *fp;
char readbuf[80];
/* Create the FIFO if it does not exist */
umask(0);
mknod(FIFO_FILE, S_IFIFO|0666, 0);
while(1)
{
fp = fopen(FIFO_FILE, "r");
fgets(readbuf, 80, fp);
printf("Received string: %s\n", readbuf);
fclose(fp);
}
return(0);
}
//有名管道client端
int main(int argc, char *argv[])
{
FILE *fp;
if ( argc != 2 ) {
printf("USAGE: fifoclient [string]\n");
exit(1);
}
if((fp = fopen(FIFO_FILE, "w")) == NULL) {
perror("fopen");
exit(1);
}
fputs(argv[1], fp);
fclose(fp);
return(0);
}
struct sigaction { void (*sa_handler)(int); void (*sa_sigaction)(int, siginfo_t *, void *); sigset_t sa_mask; int sa_flags; void (*sa_restorer)(void); };
typedef struct { int si_signo; int si_errno; int si_code; union sigval si_value; } siginfo_t; union sigval { int sival_int; void *sival_ptr; }
void ouch(int sig) { printf("\nOUCH! - I got signal %d\n", sig); } int main() { struct sigaction act; act.sa_handler = ouch; //创建空的信号屏蔽字，即不屏蔽任何信息 sigemptyset(&act.sa_mask); //使sigaction函数重置为默认行为 act.sa_flags = SA_RESETHAND; sigaction(SIGINT, &act, 0); while(1) { printf("Hello World!\n"); sleep(1); } return 0; }
static int alarm_fired = 0; void ouch(int sig) { alarm_fired = 1; } int main() { //关联信号处理函数 signal(SIGALRM, ouch); //调用alarm函数，5秒后发送信号SIGALRM alarm(5); //挂起进程 pause(); //接收到信号后，恢复正常执行 if(alarm_fired == 1) printf("Receive a signal %d\n", SIGALRM); exit(0); }
struct msgbuf { long mtype; /* type of message */ char mtext[1]; /* message text */ };
/* one msqid structure for each queue on the system */ struct msqid_ds { struct ipc_perm msg_perm; struct msg *msg_first; /* first message on queue */ struct msg *msg_last; /* last message in queue */ time_t msg_stime; /* last msgsnd time */ time_t msg_rtime; /* last msgrcv time */ time_t msg_ctime; /* last change time */ struct wait_queue *wwait; struct wait_queue *rwait; ushort msg_cbytes; ushort msg_qnum; ushort msg_qbytes; /* max number of bytes on queue */ ushort msg_lspid; /* pid of last msgsnd */ ushort msg_lrpid; /* last receive pid */ };
struct msg_st { long int msg_type; char text[BUFSIZ]; }; int main() { int running = 1; int msgid = -1; struct msg_st data; long int msgtype = 0; //注意1 //建立消息队列 msgid = msgget((key_t)1234, 0666 | IPC_CREAT); if(msgid == -1) { fprintf(stderr, "msgget failed with error: %d\n", errno); exit(EXIT_FAILURE); } //从队列中获取消息，直到遇到end消息为止 while(running) { if(msgrcv(msgid, (void*)&data, BUFSIZ, msgtype, 0) == -1) { fprintf(stderr, "msgrcv failed with errno: %d\n", errno); exit(EXIT_FAILURE); } printf("You wrote: %s\n",data.text); //遇到end结束 if(strncmp(data.text, "end", 3) == 0) running = 0; } //删除消息队列 if(msgctl(msgid, IPC_RMID, 0) == -1) { fprintf(stderr, "msgctl(IPC_RMID) failed\n"); exit(EXIT_FAILURE); } exit(EXIT_SUCCESS); }
#define MAX_TEXT 512 struct msg_st { long int msg_type; char text[MAX_TEXT]; }; int main() { int running = 1; struct msg_st data; char buffer[BUFSIZ]; int msgid = -1; //建立消息队列 msgid = msgget((key_t)1234, 0666 | IPC_CREAT); if(msgid == -1) { fprintf(stderr, "msgget failed with error: %d\n", errno); exit(EXIT_FAILURE); } //向消息队列中写消息，直到写入end while(running) { //输入数据 printf("Enter some text: "); fgets(buffer, BUFSIZ, stdin); data.msg_type = 1; //注意2 strcpy(data.text, buffer); //向队列发送数据 if(msgsnd(msgid, (void*)&data, MAX_TEXT, 0) == -1) { fprintf(stderr, "msgsnd failed\n"); exit(EXIT_FAILURE); } //输入end结束输入 if(strncmp(buffer, "end", 3) == 0) running = 0; sleep(1); } exit(EXIT_SUCCESS); }
int main() { int running = 1;//程序是否继续运行的标志 void *shm = NULL;//分配的共享内存的原始首地址 struct shared_use_st *shared;//指向shm int shmid;//共享内存标识符 //创建共享内存 shmid = shmget((key_t)1234, sizeof(struct shared_use_st), 0666|IPC_CREAT); if(shmid == -1) { fprintf(stderr, "shmget failed\n"); exit(EXIT_FAILURE); } //将共享内存连接到当前进程的地址空间 shm = shmat(shmid, 0, 0); if(shm == (void*)-1) { fprintf(stderr, "shmat failed\n"); exit(EXIT_FAILURE); } printf("\nMemory attached at %X\n", (int)shm); //设置共享内存 shared = (struct shared_use_st*)shm; shared->written = 0; while(running)//读取共享内存中的数据 { //没有进程向共享内存定数据有数据可读取 if(shared->written != 0) { printf("You wrote: %s", shared->text); sleep(rand() % 3); //读取完数据，设置written使共享内存段可写 shared->written = 0; //输入了end，退出循环（程序） if(strncmp(shared->text, "end", 3) == 0) running = 0; } else//有其他进程在写数据，不能读取数据 sleep(1); } //把共享内存从当前进程中分离 if(shmdt(shm) == -1) { fprintf(stderr, "shmdt failed\n"); exit(EXIT_FAILURE); } //删除共享内存 if(shmctl(shmid, IPC_RMID, 0) == -1) { fprintf(stderr, "shmctl(IPC_RMID) failed\n"); exit(EXIT_FAILURE); } exit(EXIT_SUCCESS); }
int main() { int running = 1; void *shm = NULL; struct shared_use_st *shared = NULL; char buffer[BUFSIZ + 1];//用于保存输入的文本 int shmid; //创建共享内存 shmid = shmget((key_t)1234, sizeof(struct shared_use_st), 0666|IPC_CREAT); if(shmid == -1) { fprintf(stderr, "shmget failed\n"); exit(EXIT_FAILURE); } //将共享内存连接到当前进程的地址空间 shm = shmat(shmid, (void*)0, 0); if(shm == (void*)-1) { fprintf(stderr, "shmat failed\n"); exit(EXIT_FAILURE); } printf("Memory attached at %X\n", (int)shm); //设置共享内存 shared = (struct shared_use_st*)shm; while(running)//向共享内存中写数据 { //数据还没有被读取，则等待数据被读取,不能向共享内存中写入文本 while(shared->written == 1) { sleep(1); printf("Waiting...\n"); } //向共享内存中写入数据 printf("Enter some text: "); fgets(buffer, BUFSIZ, stdin); strncpy(shared->text, buffer, TEXT_SZ); //写完数据，设置written使共享内存段可读 shared->written = 1; //输入了end，退出循环（程序） if(strncmp(buffer, "end", 3) == 0) running = 0; } //把共享内存从当前进程中分离 if(shmdt(shm) == -1) { fprintf(stderr, "shmdt failed\n"); exit(EXIT_FAILURE); } sleep(2); exit(EXIT_SUCCESS); }
struct sembuf{ short sem_num;//除非使用一组信号量，否则它为0 short sem_op;//信号量在一次操作中需要改变的数据，-1，即P（等待）操作+1，即V（发送信号）操作，0表示sleep直到信号量的值为0,即资源得到百分百利用。 short sem_flg;//通常为SEM_UNDO,使操作系统跟踪信号,并在进程没有释放该信号量而终止时，操作系统释放信号量;IPC_NOWAIT得不到资源立刻返回。 };
/* arg for semctl system calls. */ union semun { int val; /* value for SETVAL */ struct semid_ds *buf; /* buffer for IPC_STAT & IPC_SET */ ushort *array; /* array for GETALL & SETALL */ struct seminfo *__buf; /* buffer for IPC_INFO */ void *__pad; };
int main(int argc, char *argv[]) { char message = ‘X‘; int i = 0; //创建信号量 sem_id = semget((key_t)1234, 1, 0666 | IPC_CREAT); if(argc > 1) { //程序第一次被调用，初始化信号量 if(!set_semvalue()) { fprintf(stderr, "Failed to initialize semaphore\n"); exit(EXIT_FAILURE); } //设置要输出到屏幕中的信息，即其参数的第一个字符 message = argv[1][0]; sleep(2); } for(i = 0; i < 10; ++i) { //进入临界区 if(!semaphore_p()) exit(EXIT_FAILURE); //向屏幕中输出数据 printf("%c", message); //清理缓冲区，然后休眠随机时间 fflush(stdout); sleep(rand() % 3); //离开临界区前再一次向屏幕输出数据 printf("%c", message); fflush(stdout); //离开临界区，休眠随机时间后继续循环 if(!semaphore_v()) exit(EXIT_FAILURE); sleep(rand() % 2); } sleep(10); printf("\n%d - finished\n", getpid()); if(argc > 1) { //如果程序是第一次被调用，则在退出前删除信号量 sleep(3); del_semvalue(); } exit(EXIT_SUCCESS); } static int set_semvalue() { //用于初始化信号量，在使用信号量前必须这样做 union semun sem_union; sem_union.val = 1; if(semctl(sem_id, 0, SETVAL, sem_union) == -1) return 0; return 1; } static void del_semvalue() { //删除信号量 union semun sem_union; if(semctl(sem_id, 0, IPC_RMID, sem_union) == -1) fprintf(stderr, "Failed to delete semaphore\n"); } static int semaphore_p() { //对信号量做减1操作，即等待P（sv） struct sembuf sem_b; sem_b.sem_num = 0; sem_b.sem_op = -1;//P() sem_b.sem_flg = SEM_UNDO; if(semop(sem_id, &sem_b, 1) == -1) { fprintf(stderr, "semaphore_p failed\n"); return 0; } return 1; } static int semaphore_v() { //这是一个释放操作，它使信号量变为可用，即发送信号V（sv） struct sembuf sem_b; sem_b.sem_num = 0; sem_b.sem_op = 1;//V() sem_b.sem_flg = SEM_UNDO; if(semop(sem_id, &sem_b, 1) == -1) { fprintf(stderr, "semaphore_v failed\n"); return 0; } return 1; }
原文：https://www.cnblogs.com/killianxu/p/11332052.html