我从互联网上的many examples那里获取了以下有关如何使用inotify的代码.

然后,我尝试了以下实验：
1)在下面运行观察程序
2)在单独的外壳中,将cd插入’/ mypath’,将其中一些文件创建到您正在观看的文件夹中.例如,“日期> output.txt”一次或多次.
3)您将看到来自观察者的通知.
4)输入’ls / mypath'(甚至是’watch -n 1 / mypath’)
5)尝试“日期> / mypath中的output.txt”.您将不再看到观察者的通知.至少,这就是我在Ubuntu 12/13上进行测试时发生的情况.

关于如何解决它的任何想法？

#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <sys/types.h>
#include <sys/inotify.h>
#include <limits.h>
#include <unistd.h>


#define MAX_EVENTS 1024 /*Max. number of events to process at one go*/
#define LEN_NAME 16 /*Assuming that the length of the filename won't exceed 16 bytes*/
#define EVENT_SIZE  ( sizeof (struct inotify_event) ) /*size of one event*/
#define BUF_LEN     ( MAX_EVENTS * ( EVENT_SIZE + LEN_NAME )) /*buffer to store the data of events*/

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

  /* Initialize Inotify*/
   fd = inotify_init();
  if ( fd < 0 ) {
    perror( "Couldn't initialize inotify");
  }

  /* add watch to starting directory */
  wd = inotify_add_watch(fd, "/mypath", IN_CLOSE_WRITE | IN_CLOSE_NOWRITE); 

  if (wd == -1)
    {
      printf("Couldn't add watch to %s\n","/mypath");
    }
  else
    {
      printf("Watching:: %s\n","/mypath");
    }

  /* do it forever*/
  while(1)
    {  
      i = 0;
      length = read( fd, buffer, BUF_LEN );  


      if ( length < 0 ) {
        perror( "read" );
      }  

      while ( i < length ) {
        struct inotify_event *event = ( struct inotify_event * ) &buffer[ i ];
        if ( event->len ) {
          if ( event->mask & IN_CLOSE_WRITE) {
            if (event->mask & IN_ISDIR)
              printf( "The directory %s was Created.\n", event->name );       
            else
              printf( "The file %s was closed (write) with WD %d\n", event->name, event->wd );       
          }
          if ( event->mask & IN_CLOSE_NOWRITE) {
            if (event->mask & IN_ISDIR)
              printf( "The directory %s was Created.\n", event->name );       
            else
              printf( "The file %s was closed (nowrite) with WD %d\n", event->name, event->wd );       
          }



          i += EVENT_SIZE + event->len;
        }
      }     
    }

  /* Clean up*/
  inotify_rm_watch( fd, wd );
  close( fd );

  return 0;
}

解决方法:

您不应该将i = EVENT_SIZE event-> len;在if(event-> len)块中.如果事件的名称长度为零,则指针仍应增加EVENT_SIZE(如果将该语句放在块外会发生这种情况).我认为您可能会在inotify程序中看到一个无限循环,该循环由第一个恰好具有零长度名称的事件开始. (这正是ls会发生的情况：正在打开目录,而不是其文件,因此name字段中没有任何内容.)