blocks|key|2093820|text|fd是inotify_init()或inotify_init1()的返回值。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2093821|first,++use+inotify_init()+or+inotify_init1()+to+initialize+an+inotify+
instance;
second,+return+a+file+descriptor+(with+a+new+inotify+event+queue)+fd+;
third,+use+the+returned+fd+in+inotify_add_watch+to+monitor+the+file+path+
you+want+to+monitor.|code-block|syntax|javascript|2093822|示例代码：|2093823|++int+fd+=+inotify_init();++++++++++++++++
++int+wd+=+inotify_add_watch(fd,+argv[1],+IN_ALL_EVENTS);++++++++++++++++++
++
++for+(;;)+

++{+++
+++++++fd_set+fds;+++
+++++++FD_ZERO(&fds);++++++++++++++++
+++++++FD_SET(fd,+&fds);+++


+++++++if+(select(fd+%2B+1,+&fds,+NULL,+NULL,+NULL)+>+0)+++++++

+++++++{+++
+++++++++++int+len,+index+=+0;+++
+++++++++++while+(((len+=+read(fd,+&buf,+sizeof(buf)))+<+0)+&&+(errno+==+EINTR));++++++
+++++++++++while+(index+<+len)+

+++++++++++{+++
++++++++++++++++++event+=+(struct+inotify_event+*)(buf+%2B+index);++++++++++++++++++++++
++++++++++++++++++_inotify_event_handler(event);+++++++++++++++++++++++++++++++++++++++++++++
++++++++++++++++++index+%2B=+sizeof(struct+inotify_event)+%2B+event->len;+++++++++++++
+++++++++++}+++
+++++++}+++
++}+++
++
++inotify_rm_watch(fd,+wd);+++++++++++++
++
++return+0;++|2093824|entityMap^0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|N|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|O|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|K|3|-4|5|6|7|Q|8|@]|9|@]|A|$]]]|L|$]]

fd is the return value of inotify_init() or inotify_init1().
<pre><code>first, use inotify_init() or inotify_init1() to initialize an inotify 
instance;
second, return a file descriptor (with a new inotify event queue) fd ;
third, use the returned fd in inotify_add_watch to monitor the file path 
you want to monitor.
</code></pre>
example code :
<pre><code> int fd = inotify_init(); 
 int wd = inotify_add_watch(fd, argv[1], IN_ALL_EVENTS); 
 
 for (;;) 

 { 
 fd_set fds; 
 FD_ZERO(&amp;fds); 
 FD_SET(fd, &amp;fds); 


 if (select(fd + 1, &amp;fds, NULL, NULL, NULL) &gt; 0) 

 { 
 int len, index = 0; 
 while (((len = read(fd, &amp;buf, sizeof(buf))) &lt; 0) &amp;&amp; (errno == EINTR)); 
 while (index &lt; len) 

 { 
 event = (struct inotify_event *)(buf + index); 
 _inotify_event_handler(event); 
 index += sizeof(struct inotify_event) + event-&gt;len; 
 } 
 } 
 } 
 
 inotify_rm_watch(fd, wd); 
 
 return 0; 
</code></pre>

blocks|key|2093873|text|文件描述符基本上是某些输入/输出资源的标识符。当您使用inotify时，您需要使用inotify_init初始化一个实例，该实例返回一个文件描述符，然后您可以使用inotify_add_watch将要查看的文件添加到实例中。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|2093874|因此，在回答您的问题时，inotify_add_watch中的fd参数是inotify实例的文件描述符，由inotify_init调用返回。|2093875|entityMap^0|15|C|29|H|0|C|H|1H|C|0^^$0|@$1|2|3|4|5|6|7|J|8|@$9|K|A|L|B|C]|$9|M|A|N|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|O|8|@$9|P|A|Q|B|C]|$9|R|A|S|B|C]]|D|@]|E|$]]|$1|H|3|-4|5|6|7|T|8|@]|D|@]|E|$]]]|I|$]]

A file descriptor is basically an identifier of some input/output resource. When you work with inotify, you need to initialize an instance with <code>inotify_init</code>, which returns a file descriptor, then you can add the files that you want to watch to the instance with <code>inotify_add_watch</code>.
So, answering your question, the fd argument in <code>inotify_add_watch</code> is the file descriptor of a inotify instance, returned by an <code>inotify_init</code> call.

I am working on a project to monitor folders and files, but I don't know how <code>inotify_add_watch</code> works. I searched online to see what <code>fd</code> does but I don't understand <a href="https://man7.org/linux/man-pages/man2/inotify_add_watch.2.html" rel="nofollow noreferrer">man page</a>:
<blockquote>
The <code>fd</code> argument is a file descriptor referring to the inotify instance whose watch list is to be modified.
</blockquote>
What does that mean?

What is inotify_add_watch's fd parameter?

翻译质量差，导致语言生硬或混乱。

没有提供实际的解决方法或示例。

解答不清晰，无法理解或解决问题。

页面排版不美观，阅读体验差。

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我正在进行一个监视文件夹和文件的项目，但我不知道inotify_add_watch是如何工作的。我在网上搜索fd做了什么，但我不懂fd参数是一个文件描述符，它引用了要修改其监视列表的inotify实例。那是什么意思？

问inotify_add_watch的fd参数是什么？
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问inotify_add_watch的fd参数是什么？EN