linux c 监视文件变化

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/inotify.h>
#include <unistd.h>

#define EVENT_SIZE  ( sizeof (struct inotify_event) )
#define BUF_LEN     ( 1024 * ( EVENT_SIZE + 16 ) )

int main(int argc, char **argv) {
    int length, i = 0;
    int fd;
    int wd;
    char buffer[BUF_LEN];

    if (argc != 2) {
        printf("Usage: %s <file_or_directory>
", argv[0]);
        exit(1);
    }

    fd = inotify_init();
    if (fd < 0) {
        perror("inotify_init");
        exit(1);
    }

    wd = inotify_add_watch(fd, argv[1], IN_MODIFY | IN_CREATE | IN_DELETE);
    if (wd < 0) {
        perror("inotify_add_watch");
        exit(1);
    }

    length = read(fd, buffer, BUF_LEN);
    if (length < 0) {
        perror("read");
        exit(1);
    }

    while (i < length) {
        struct inotify_event *event = (struct inotify_event *)&buffer[i];
        if (event->len) {
            if (event->mask & IN_CREATE) {
                printf("File %s created.
", event->name);
            } else if (event->mask & IN_DELETE) {
                printf("File %s deleted.
", event->name);
            } else if (event->mask & IN_MODIFY) {
                printf("File %s modified.
", event->name);
            }
        }
        i += EVENT_SIZE + event->len;
    }

    inotify_rm_watch(fd, wd);
    close(fd);

    return 0;
}