inotify+epoll tail

#include <fcntl.h>
#include <stdio.h>
#include <string.h>
#include <errno.h>
#include <sys/inotify.h>
#include <sys/epoll.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <errno.h>

#define BUFSIZE 81

int main(int argc, char* argv[]) {
    printf("LOG:argc = %d\n", argc);
    printf("LOG:argc[1] = %s\n", argv[1]);
    int fd = inotify_init();
    printf("LOG:fd = %d\n", fd);
    if (fd < 0) {
        printf("LOG:inotify_init error\n");
        return -1;
    }
    int wd = inotify_add_watch(fd, argv[1], IN_MODIFY);
    printf("LOG:wd = %d\n", wd);
    if (wd < 0) {
        printf("LOG:inotify_add_watch error");
        return -1;
    }

    int epfd = epoll_create(1);
    printf("LOG:epfd = %d\n", epfd);
    if (epfd < 0) {
        printf("LOG:epoll_create error\n");
        return -1;
    }

    struct epoll_event event;
    event.events = EPOLLIN | EPOLLET;
    event.data.fd = fd;

    int re = epoll_ctl(epfd, EPOLL_CTL_ADD, fd, &event);     
    printf("LOG:re = %d\n", re);
    if (re != 0) {
        printf("LOG:epoll_ctl error:%s\n", strerror(errno));
        return -1;
    }

    ssize_t n;
    ssize_t tmp;
    int file_fd = open(argv[1], O_RDONLY);
    printf("LOG:file_fd = %d\n", file_fd);
    if (file_fd == -1) {
        printf("LOG:open error\n");
        return -1;
    }
    char buf[BUFSIZE];
    
    int seek_re;    

    while (1) {
        int num = epoll_wait(epfd, &event, 1, -1);
        printf("LOG:epoll_wait num = %d\n", num);
        if (num > 0) {
            tmp = read(fd, buf, BUFSIZE);
            seek_re = lseek(file_fd, (off_t) -1, SEEK_CUR);
            n = read(file_fd, buf, BUFSIZE);
            if (n == -1) {
                printf("break\n");
                break;
            }
            if (n > 0) {
                printf("%s", buf);
            }
        }
        printf("LOG:new loop\n");
    }
    
    return 0;
}