10.2 基于事件服务器

服务端

  1. #include <event2/event-config.h>
  3. #include <sys/types.h>
  4. #include <sys/stat.h>
  5. #include <sys/queue.h>
  6. #include <unistd.h>
  7. #include <sys/time.h>
  8. #include <fcntl.h>
  9. #include <stdlib.h>
  10. #include <stdio.h>
  11. #include <string.h>
  12. #include <errno.h>
  14. #include <event.h>
  16. static void
  17. fifo_read(evutil_socket_t fd, short event, void *arg)
  18. {
  19.         char buf[255];
  20.         int len;
  21.         struct event *ev = arg;
  23.         /* Reschedule this event */
  24.         event_add(ev, NULL);
  26.         fprintf(stderr, "fifo_read called with fd: %d, event: %d, arg: %p\n",
  27.             (int)fd, event, arg);
  28.         len = read(fd, buf, sizeof(buf) - 1);
  30.         if (len == -1) {
  31.                 perror("read");
  32.                 return;
  33.         } else if (len == 0) {
  34.                 fprintf(stderr, "Connection closed\n");
  35.                 return;
  36.         }
  38.         buf[len] = '\0';
  40.         fprintf(stdout, "Read: %s\n", buf);
  41. }
  43. int
  44. main(int argc, char **argv)
  45. {
  46.         struct event evfifo;
  48.         struct stat st;
  49.         const char *fifo = "event.fifo";
  50.         int socket;
  52.         if (lstat(fifo, &st) == 0) {
  53.                 if ((st.st_mode & S_IFMT) == S_IFREG) {
  54.                         errno = EEXIST;
  55.                         perror("lstat");
  56.                         exit(1);
  57.                 }
  58.         }
  60.         unlink(fifo);
  61.         if (mkfifo(fifo, 0600) == -1) {
  62.                 perror("mkfifo");
  63.                 exit(1);
  64.         }
  66.         /* Linux pipes are broken, we need O_RDWR instead of O_RDONLY */
  67.         socket = open(fifo, O_RDONLY | O_NONBLOCK, 0);
  69.         if (socket == -1) {
  70.                 perror("open");
  71.                 exit(1);
  72.         }
  74.         fprintf(stderr, "Write data to %s\n", fifo);
  76.         /* Initalize the event library */
  77.         event_init();
  79.         /* Initalize one event */
  80.         event_set(&evfifo, socket, EV_READ, fifo_read, &evfifo);
  82.         /* Add it to the active events, without a timeout */
  83.         event_add(&evfifo, NULL);
  85.         event_dispatch();
  87.         return (0);
  88. }

客户端

  1. #include <stdio.h>
  2. #include <stdlib.h>
  3. #include <string.h>
  4. #include <unistd.h>
  5. #include <fcntl.h>
  6. #include <pthread.h>
  8. int main(int argc, char *argv[])
  9. {
  10.     int fd = 0;
  11.     char *str = "hello libevent!";
  13.     fd = open("event.fifo", O_RDWR);
  14.     if (fd < 0) {
  15.         perror("open error");
  16.         exit(1);
  17.     }
  19.     while (1) {
  20.         write(fd, str, strlen(str));
  21.         sleep(1);
  22.     }
  24.     close(fd);
  26.         return 0;
  27. }