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<meta name="description" content="epool基本概念是什么？改进的pool，一种I/O多路复用技术，可管理大批量文件描述符。 工作原理？ 内核中，一切皆文件，epoll向内核注册一个文件系统，用于存储要管理的文件描述符号。调用epoll_create时，会在虚拟文件系统中创建一个file节点服务epool同时也会创建就绪事件list链表。操作系统启动后，会开辟出自己的高速cache，socket问价描述符会以红黑树存入cache，">
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<meta name="twitter:description" content="epool基本概念是什么？改进的pool，一种I/O多路复用技术，可管理大批量文件描述符。 工作原理？ 内核中，一切皆文件，epoll向内核注册一个文件系统，用于存储要管理的文件描述符号。调用epoll_create时，会在虚拟文件系统中创建一个file节点服务epool同时也会创建就绪事件list链表。操作系统启动后，会开辟出自己的高速cache，socket问价描述符会以红黑树存入cache，">


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          <h1 class="post-title" itemprop="name headline">epool基本用法</h1>
        

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        <h2 id="epool基本概念"><a href="#epool基本概念" class="headerlink" title="epool基本概念"></a>epool基本概念</h2><h3 id="是什么？"><a href="#是什么？" class="headerlink" title="是什么？"></a>是什么？</h3><p>改进的pool，一种I/O多路复用技术，可管理大批量文件描述符。</p>
<h3 id="工作原理？"><a href="#工作原理？" class="headerlink" title="工作原理？"></a>工作原理？</h3><blockquote>
<p>内核中，一切皆文件，epoll向内核注册一个文件系统，用于存储要管理的文件描述符号。调用epoll_create时，会在虚拟文件系统中创建一个file节点服务epool同时也会创建就绪事件list链表。<br>操作系统启动后，会开辟出自己的高速cache，socket问价描述符会以红黑树存入cache，方便查找、插入、删除。<br>    epool_ctl，把socket放到epool文件系统里file对应的红黑树，也会注册一个回调函数，文件描述符有信号后，会调用该组册函数，内核把网卡数据copy到内核中把socket插入就绪列表中。<br>    epoll_wait调用时候，看一眼就绪列表，所以效率很高。监控百万描述符，但是准备就绪fd却很少。</p>
</blockquote>
<a id="more"></a>
<h3 id="适用场景？"><a href="#适用场景？" class="headerlink" title="适用场景？"></a>适用场景？</h3><p>非常适用大量并发连接中只有少量活跃连接情况，且在该情况下CPU适用率很低。</p>
<h3 id="可能缺点？"><a href="#可能缺点？" class="headerlink" title="可能缺点？"></a>可能缺点？</h3><p>所有socket基本都是活跃的，比如在一个高速的LAN环境，使用epool可能会比select／pool效率低</p>
<h3 id="分为LT和ET"><a href="#分为LT和ET" class="headerlink" title="分为LT和ET"></a>分为LT和ET</h3><p>LT和ET作用在epool_wait过程中，LT模式下，只要一个文件描述符没有处理完，后续再次调用epool_wait时也会返回。实现过程为，内核会把socket事件插入就绪链表，epool_wait调用会被把就绪的文件描述符拷入用户态，清空就绪链表，如果是ET则额外检测如果存在没有处理文件描述符，则将再次放入就绪列表中。</p>
<h2 id="epool例子"><a href="#epool例子" class="headerlink" title="epool例子"></a>epool例子</h2><h3 id="epoll-create函数"><a href="#epoll-create函数" class="headerlink" title="epoll_create函数"></a>epoll_create函数</h3><p>用途：创建一个epool事件管理并返回描述符号<br><figure class="highlight c"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br></pre></td><td class="code"><pre><span class="line"><span class="meta">#<span class="meta-keyword">include</span> <span class="meta-string">&lt;sys/epoll.h&gt;</span></span></span><br><span class="line"><span class="function"><span class="keyword">int</span> <span class="title">epoll_create</span><span class="params">(<span class="keyword">int</span> size)</span></span>;</span><br></pre></td></tr></table></figure></p>
<p>参数：size 最大fd数<br>返回值：epool使用的文件描述符</p>
<ul>
<li>-1 失败</li>
<li>>= 0 成功</li>
</ul>
<h3 id="epoll-ctl函数"><a href="#epoll-ctl函数" class="headerlink" title="epoll_ctl函数"></a>epoll_ctl函数</h3><p>用途：控制epoll事件，添加修改删除事件<br><figure class="highlight c"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br></pre></td><td class="code"><pre><span class="line"><span class="meta">#<span class="meta-keyword">include</span> <span class="meta-string">&lt;sys/epoll.h&gt;</span></span></span><br><span class="line"><span class="function"><span class="keyword">int</span> <span class="title">epoll_ctl</span><span class="params">(<span class="keyword">int</span> epfd, <span class="keyword">int</span> op, <span class="keyword">int</span> fd, struct epoll_event *event)</span></span>;</span><br></pre></td></tr></table></figure></p>
<p>参数：</p>
<blockquote>
<p>epfd:epoll_create的返回值<br>op:要进行的操作例如注册事件，可能的取值EPOLL_CTL_ADD 注册、EPOLL_CTL_MOD 修 改、EPOLL_CTL_DEL 删除<br>fd:要在epool事件管理上加入删除或者修改的文件描述符<br>event:event.data.fd 要处理的文件描述符<br>event:event.events = EPOLLIN|EPOLLET;<br>EPOLLIN ：表示对应的文件描述符可以读；<br>EPOLLOUT：表示对应的文件描述符可以写；<br>EPOLLPRI：表示对应的文件描述符有紧急的数据可读<br>EPOLLERR：表示对应的文件描述符发生错误；<br>EPOLLHUP：表示对应的文件描述符被挂断；<br>EPOLLET：边缘触发；</p>
</blockquote>
<p>返回值：成功返回0，失败返回-1<br>    When successful, epoll_ctl() returns zero.  When an error occurs, epoll_ctl() returns -1 and errno is set appropriately</p>
<h3 id="epool-wait函数"><a href="#epool-wait函数" class="headerlink" title="epool_wait函数"></a>epool_wait函数</h3><p>用途：返回IO事件就绪的fd<br><figure class="highlight c"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br></pre></td><td class="code"><pre><span class="line"><span class="function"><span class="keyword">int</span> <span class="title">epoll_wait</span><span class="params">(<span class="keyword">int</span> epfd, struct epoll_event *events,</span></span></span><br><span class="line"><span class="function"><span class="params">                      <span class="keyword">int</span> maxevents, <span class="keyword">int</span> timeout)</span></span>;</span><br></pre></td></tr></table></figure></p>
<p>参数：<br>epfd：epoll_create的返回值<br>events：取出内核结果的事件数组<br>maxevents：要处理的事件数<br>timeout：等待IO发生超时值<br>            -1 阻塞直到有事件<br>            0 非阻塞<br>            &gt;0： 阻塞时间，单位毫秒</p>
<h3 id="epoool函数实例"><a href="#epoool函数实例" class="headerlink" title="epoool函数实例"></a>epoool函数实例</h3><figure class="highlight c"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br><span class="line">15</span><br><span class="line">16</span><br><span class="line">17</span><br><span class="line">18</span><br><span class="line">19</span><br><span class="line">20</span><br><span class="line">21</span><br><span class="line">22</span><br><span class="line">23</span><br><span class="line">24</span><br><span class="line">25</span><br><span class="line">26</span><br><span 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class="line">149</span><br><span class="line">150</span><br><span class="line">151</span><br><span class="line">152</span><br><span class="line">153</span><br><span class="line">154</span><br><span class="line">155</span><br><span class="line">156</span><br><span class="line">157</span><br><span class="line">158</span><br><span class="line">159</span><br><span class="line">160</span><br><span class="line">161</span><br></pre></td><td class="code"><pre><span class="line"><span class="meta">#<span class="meta-keyword">include</span>  <span class="meta-string">&lt;unistd.h&gt;</span></span></span><br><span class="line"><span class="meta">#<span class="meta-keyword">include</span>  <span class="meta-string">&lt;sys/types.h&gt;       /* basic system data types */</span></span></span><br><span class="line"><span class="meta">#<span class="meta-keyword">include</span>  <span class="meta-string">&lt;sys/socket.h&gt;      /* basic socket definitions */</span></span></span><br><span class="line"><span class="meta">#<span class="meta-keyword">include</span>  <span class="meta-string">&lt;netinet/in.h&gt;      /* sockaddr_in&#123;&#125; and other Internet defns */</span></span></span><br><span class="line"><span class="meta">#<span class="meta-keyword">include</span>  <span class="meta-string">&lt;arpa/inet.h&gt;       /* inet(3) functions */</span></span></span><br><span class="line"><span class="meta">#<span class="meta-keyword">include</span> <span class="meta-string">&lt;sys/epoll.h&gt; /* epoll function */</span></span></span><br><span class="line"><span class="meta">#<span class="meta-keyword">include</span> <span class="meta-string">&lt;fcntl.h&gt;     /* nonblocking */</span></span></span><br><span class="line"><span class="meta">#<span class="meta-keyword">include</span> <span class="meta-string">&lt;sys/resource.h&gt; /*setrlimit */</span></span></span><br><span class="line"></span><br><span class="line"><span class="meta">#<span class="meta-keyword">include</span> <span class="meta-string">&lt;stdlib.h&gt;</span></span></span><br><span class="line"><span class="meta">#<span class="meta-keyword">include</span> <span class="meta-string">&lt;errno.h&gt;</span></span></span><br><span class="line"><span class="meta">#<span class="meta-keyword">include</span> <span class="meta-string">&lt;stdio.h&gt;</span></span></span><br><span class="line"><span class="meta">#<span class="meta-keyword">include</span> <span class="meta-string">&lt;string.h&gt;</span></span></span><br><span class="line"></span><br><span class="line"><span class="meta">#<span class="meta-keyword">define</span> MAXEPOLLSIZE 10000</span></span><br><span class="line"><span class="meta">#<span class="meta-keyword">define</span> MAXLINE 10240</span></span><br><span class="line"><span class="function"><span class="keyword">int</span> <span class="title">handle</span><span class="params">(<span class="keyword">int</span> connfd)</span></span>;</span><br><span class="line"><span class="function"><span class="keyword">int</span> <span class="title">setnonblocking</span><span class="params">(<span class="keyword">int</span> sockfd)</span></span></span><br><span class="line"><span class="function"></span>&#123;</span><br><span class="line">    <span class="keyword">if</span> (fcntl(sockfd, F_SETFL, fcntl(sockfd, F_GETFD, <span class="number">0</span>)|O_NONBLOCK) == <span class="number">-1</span>) &#123;</span><br><span class="line">        <span class="keyword">return</span> <span class="number">-1</span>;</span><br><span class="line">    &#125;</span><br><span class="line">    <span class="keyword">return</span> <span class="number">0</span>;</span><br><span class="line">&#125;</span><br><span class="line"></span><br><span class="line"><span class="function"><span class="keyword">int</span> <span class="title">main</span><span class="params">(<span class="keyword">int</span> argc, <span class="keyword">char</span> **argv)</span></span></span><br><span class="line"><span class="function"></span>&#123;</span><br><span class="line">    <span class="keyword">int</span>  servPort = <span class="number">8080</span>;</span><br><span class="line">    <span class="keyword">int</span> listenq = <span class="number">1024</span>;</span><br><span class="line"></span><br><span class="line">    <span class="keyword">int</span> listenfd, connfd, kdpfd, nfds, n, nread, curfds,acceptCount = <span class="number">0</span>;</span><br><span class="line">    <span class="class"><span class="keyword">struct</span> <span class="title">sockaddr_in</span> <span class="title">servaddr</span>, <span class="title">cliaddr</span>;</span></span><br><span class="line">    <span class="keyword">socklen_t</span> socklen = <span class="keyword">sizeof</span>(struct sockaddr_in);</span><br><span class="line">    <span class="class"><span class="keyword">struct</span> <span class="title">epoll_event</span> <span class="title">ev</span>;</span></span><br><span class="line">    <span class="class"><span class="keyword">struct</span> <span class="title">epoll_event</span> <span class="title">events</span>[<span class="title">MAXEPOLLSIZE</span>];</span></span><br><span class="line">    <span class="class"><span class="keyword">struct</span> <span class="title">rlimit</span> <span class="title">rt</span>;</span></span><br><span class="line">    <span class="keyword">char</span> buf[MAXLINE];</span><br><span class="line"></span><br><span class="line">    <span class="comment">/* 设置每个进程允许打开的最大文件数 */</span></span><br><span class="line">    rt.rlim_max = rt.rlim_cur = MAXEPOLLSIZE;</span><br><span class="line">    <span class="keyword">if</span> (setrlimit(RLIMIT_NOFILE, &amp;rt) == <span class="number">-1</span>)</span><br><span class="line">    &#123;</span><br><span class="line">        perror(<span class="string">"setrlimit error"</span>);</span><br><span class="line">        <span class="keyword">return</span> <span class="number">-1</span>;</span><br><span class="line">    &#125;</span><br><span class="line"></span><br><span class="line"></span><br><span class="line">    bzero(&amp;servaddr, <span class="keyword">sizeof</span>(servaddr));</span><br><span class="line">    servaddr.sin_family = AF_INET;</span><br><span class="line">    servaddr.sin_addr.s_addr = htonl (INADDR_ANY);</span><br><span class="line">    servaddr.sin_port = htons (servPort);</span><br><span class="line"></span><br><span class="line">    listenfd = socket(AF_INET, SOCK_STREAM, <span class="number">0</span>);</span><br><span class="line">    <span class="keyword">if</span> (listenfd == <span class="number">-1</span>) &#123;</span><br><span class="line">        perror(<span class="string">"can't create socket file"</span>);</span><br><span class="line">        <span class="keyword">return</span> <span class="number">-1</span>;</span><br><span class="line">    &#125;</span><br><span class="line"></span><br><span class="line">    <span class="keyword">int</span> opt = <span class="number">1</span>;</span><br><span class="line">    setsockopt(listenfd, SOL_SOCKET, SO_REUSEADDR, &amp;opt, <span class="keyword">sizeof</span>(opt));</span><br><span class="line"></span><br><span class="line">    <span class="keyword">if</span> (setnonblocking(listenfd) &lt; <span class="number">0</span>) &#123;</span><br><span class="line">        perror(<span class="string">"setnonblock error"</span>);</span><br><span class="line">    &#125;</span><br><span class="line"></span><br><span class="line">    <span class="keyword">if</span> (bind(listenfd, (struct sockaddr *) &amp;servaddr, <span class="keyword">sizeof</span>(struct sockaddr)) == <span class="number">-1</span>)</span><br><span class="line">    &#123;</span><br><span class="line">        perror(<span class="string">"bind error"</span>);</span><br><span class="line">        <span class="keyword">return</span> <span class="number">-1</span>;</span><br><span class="line">    &#125;</span><br><span class="line">    <span class="keyword">if</span> (listen(listenfd, listenq) == <span class="number">-1</span>)</span><br><span class="line">    &#123;</span><br><span class="line">        perror(<span class="string">"listen error"</span>);</span><br><span class="line">        <span class="keyword">return</span> <span class="number">-1</span>;</span><br><span class="line">    &#125;</span><br><span class="line">    <span class="comment">/* 创建 epoll 句柄，把监听 socket 加入到 epoll 集合里 */</span></span><br><span class="line">    kdpfd = epoll_create(MAXEPOLLSIZE);</span><br><span class="line">    ev.events = EPOLLIN | EPOLLET;</span><br><span class="line">    ev.data.fd = listenfd;</span><br><span class="line">    <span class="keyword">if</span> (epoll_ctl(kdpfd, EPOLL_CTL_ADD, listenfd, &amp;ev) &lt; <span class="number">0</span>)</span><br><span class="line">    &#123;</span><br><span class="line">        <span class="built_in">fprintf</span>(<span class="built_in">stderr</span>, <span class="string">"epoll set insertion error: fd=%d\n"</span>, listenfd);</span><br><span class="line">        <span class="keyword">return</span> <span class="number">-1</span>;</span><br><span class="line">    &#125;</span><br><span class="line">    curfds = <span class="number">1</span>;</span><br><span class="line"></span><br><span class="line">    <span class="built_in">printf</span>(<span class="string">"epollserver startup,port %d, max connection is %d, backlog is %d\n"</span>, servPort, MAXEPOLLSIZE, listenq);</span><br><span class="line"></span><br><span class="line">    <span class="keyword">for</span> (;;) &#123;</span><br><span class="line">        <span class="comment">/* 等待有事件发生 */</span></span><br><span class="line">        nfds = epoll_wait(kdpfd, events, curfds, <span class="number">-1</span>);</span><br><span class="line">        <span class="keyword">if</span> (nfds == <span class="number">-1</span>)</span><br><span class="line">        &#123;</span><br><span class="line">            perror(<span class="string">"epoll_wait"</span>);</span><br><span class="line">            <span class="keyword">continue</span>;</span><br><span class="line">        &#125;</span><br><span class="line">        <span class="comment">/* 处理所有事件 */</span></span><br><span class="line">        <span class="keyword">for</span> (n = <span class="number">0</span>; n &lt; nfds; ++n)</span><br><span class="line">        &#123;</span><br><span class="line">            <span class="keyword">if</span> (events[n].data.fd == listenfd)</span><br><span class="line">            &#123;</span><br><span class="line">                connfd = accept(listenfd, (struct sockaddr *)&amp;cliaddr,&amp;socklen);</span><br><span class="line">                <span class="keyword">if</span> (connfd &lt; <span class="number">0</span>)</span><br><span class="line">                &#123;</span><br><span class="line">                    perror(<span class="string">"accept error"</span>);</span><br><span class="line">                    <span class="keyword">continue</span>;</span><br><span class="line">                &#125;</span><br><span class="line"></span><br><span class="line">                <span class="built_in">sprintf</span>(buf, <span class="string">"accept form %s:%d\n"</span>, inet_ntoa(cliaddr.sin_addr), cliaddr.sin_port);</span><br><span class="line">                <span class="built_in">printf</span>(<span class="string">"%d:%s"</span>, ++acceptCount, buf);</span><br><span class="line"></span><br><span class="line">                <span class="keyword">if</span> (curfds &gt;= MAXEPOLLSIZE) &#123;</span><br><span class="line">                    <span class="built_in">fprintf</span>(<span class="built_in">stderr</span>, <span class="string">"too many connection, more than %d\n"</span>, MAXEPOLLSIZE);</span><br><span class="line">                    close(connfd);</span><br><span class="line">                    <span class="keyword">continue</span>;</span><br><span class="line">                &#125;</span><br><span class="line">                <span class="keyword">if</span> (setnonblocking(connfd) &lt; <span class="number">0</span>) &#123;</span><br><span class="line">                    perror(<span class="string">"setnonblocking error"</span>);</span><br><span class="line">                &#125;</span><br><span class="line">                ev.events = EPOLLIN | EPOLLET;</span><br><span class="line">                ev.data.fd = connfd;</span><br><span class="line">                <span class="keyword">if</span> (epoll_ctl(kdpfd, EPOLL_CTL_ADD, connfd, &amp;ev) &lt; <span class="number">0</span>)</span><br><span class="line">                &#123;</span><br><span class="line">                    <span class="built_in">fprintf</span>(<span class="built_in">stderr</span>, <span class="string">"add socket '%d' to epoll failed: %s\n"</span>, connfd, strerror(errno));</span><br><span class="line">                    <span class="keyword">return</span> <span class="number">-1</span>;</span><br><span class="line">                &#125;</span><br><span class="line">                curfds++;</span><br><span class="line">                <span class="keyword">continue</span>;</span><br><span class="line">            &#125;</span><br><span class="line">            <span class="comment">// 处理客户端请求</span></span><br><span class="line">            <span class="keyword">if</span> (handle(events[n].data.fd) &lt; <span class="number">0</span>) &#123;</span><br><span class="line">                epoll_ctl(kdpfd, EPOLL_CTL_DEL, events[n].data.fd,&amp;ev);</span><br><span class="line">                curfds--;</span><br><span class="line"></span><br><span class="line"></span><br><span class="line">            &#125;</span><br><span class="line">        &#125;</span><br><span class="line">    &#125;</span><br><span class="line">    close(listenfd);</span><br><span class="line">    <span class="keyword">return</span> <span class="number">0</span>;</span><br><span class="line">&#125;</span><br><span class="line"><span class="function"><span class="keyword">int</span> <span class="title">handle</span><span class="params">(<span class="keyword">int</span> connfd)</span> </span>&#123;</span><br><span class="line">    <span class="keyword">int</span> nread;</span><br><span class="line">    <span class="keyword">char</span> buf[MAXLINE];</span><br><span class="line">    nread = read(connfd, buf, MAXLINE);<span class="comment">//读取客户端socket流</span></span><br><span class="line"></span><br><span class="line">    <span class="keyword">if</span> (nread == <span class="number">0</span>) &#123;</span><br><span class="line">        <span class="built_in">printf</span>(<span class="string">"client close the connection\n"</span>);</span><br><span class="line">        close(connfd);</span><br><span class="line">        <span class="keyword">return</span> <span class="number">-1</span>;</span><br><span class="line">    &#125;</span><br><span class="line">    <span class="keyword">if</span> (nread &lt; <span class="number">0</span>) &#123;</span><br><span class="line">        perror(<span class="string">"read error"</span>);</span><br><span class="line">        close(connfd);</span><br><span class="line">        <span class="keyword">return</span> <span class="number">-1</span>;</span><br><span class="line">    &#125;</span><br><span class="line">    <span class="built_in">printf</span>(<span class="string">"recv:%s\n"</span>,buf);</span><br><span class="line">    write(connfd, buf, nread);<span class="comment">//响应客户端</span></span><br><span class="line">    <span class="built_in">printf</span>(<span class="string">"send:%s\n"</span>,buf);</span><br><span class="line">    <span class="keyword">return</span> <span class="number">0</span>;</span><br><span class="line">&#125;</span><br></pre></td></tr></table></figure>

      
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              <div class="post-toc-content"><ol class="nav"><li class="nav-item nav-level-2"><a class="nav-link" href="#epool基本概念"><span class="nav-number">1.</span> <span class="nav-text">epool基本概念</span></a><ol class="nav-child"><li class="nav-item nav-level-3"><a class="nav-link" href="#是什么？"><span class="nav-number">1.1.</span> <span class="nav-text">是什么？</span></a></li><li class="nav-item nav-level-3"><a class="nav-link" href="#工作原理？"><span class="nav-number">1.2.</span> <span class="nav-text">工作原理？</span></a></li><li class="nav-item nav-level-3"><a class="nav-link" href="#适用场景？"><span class="nav-number">1.3.</span> <span class="nav-text">适用场景？</span></a></li><li class="nav-item nav-level-3"><a class="nav-link" href="#可能缺点？"><span class="nav-number">1.4.</span> <span class="nav-text">可能缺点？</span></a></li><li class="nav-item nav-level-3"><a class="nav-link" href="#分为LT和ET"><span class="nav-number">1.5.</span> <span class="nav-text">分为LT和ET</span></a></li></ol></li><li class="nav-item nav-level-2"><a class="nav-link" href="#epool例子"><span class="nav-number">2.</span> <span class="nav-text">epool例子</span></a><ol class="nav-child"><li class="nav-item nav-level-3"><a class="nav-link" href="#epoll-create函数"><span class="nav-number">2.1.</span> <span class="nav-text">epoll_create函数</span></a></li><li class="nav-item nav-level-3"><a class="nav-link" href="#epoll-ctl函数"><span class="nav-number">2.2.</span> <span class="nav-text">epoll_ctl函数</span></a></li><li class="nav-item nav-level-3"><a class="nav-link" href="#epool-wait函数"><span class="nav-number">2.3.</span> <span class="nav-text">epool_wait函数</span></a></li><li class="nav-item nav-level-3"><a class="nav-link" href="#epoool函数实例"><span class="nav-number">2.4.</span> <span class="nav-text">epoool函数实例</span></a></li></ol></li></ol></div>
            

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    var isXml = true;
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      $('.search-result-list').remove();
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      $('.search-popup-overlay').click(onPopupClose);
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      $localSearchInput.attr("autocapitalize", "none");
      $localSearchInput.attr("autocorrect", "off");
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      // start loading animation
      $("body")
        .append('<div class="search-popup-overlay local-search-pop-overlay">' +
          '<div id="search-loading-icon">' +
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          var resultContent = document.getElementById(content_id);
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                      end: end,
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                  var slicesOfContent = [];
                  while (indexOfContent.length != 0) {
                    var item = indexOfContent[indexOfContent.length - 1];
                    var position = item.position;
                    var word = item.word;
                    // cut out 100 characters
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                    var end = position + 80;
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                    if (end < position + word.length) {
                      end = position + word.length;
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                    if(end > content.length){
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                  // sort slices in content by search text's count and hits' count

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                  // highlight title and content

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                  var resultItem = '';

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                  resultItem += "</li>";
                  resultItems.push({
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                    searchTextCount: searchTextCount,
                    hitCount: hitCount,
                    id: resultItems.length
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            };
            if (keywords.length === 1 && keywords[0] === "") {
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                } else if (resultLeft.hitCount !== resultRight.hitCount) {
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                } else {
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              var searchResultList = '<ul class=\"search-result-list\">';
              resultItems.forEach(function (result) {
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              })
              searchResultList += "</ul>";
              resultContent.innerHTML = searchResultList;
            }
          }

          if ('auto' === 'auto') {
            input.addEventListener('input', inputEventFunction);
          } else {
            $('.search-icon').click(inputEventFunction);
            input.addEventListener('keypress', function (event) {
              if (event.keyCode === 13) {
                inputEventFunction();
              }
            });
          }

          // remove loading animation
          $(".local-search-pop-overlay").remove();
          $('body').css('overflow', '');

          proceedsearch();
        }
      });
    }

    // handle and trigger popup window;
    $('.popup-trigger').click(function(e) {
      e.stopPropagation();
      if (isfetched === false) {
        searchFunc(path, 'local-search-input', 'local-search-result');
      } else {
        proceedsearch();
      };
    });

    $('.popup-btn-close').click(onPopupClose);
    $('.popup').click(function(e){
      e.stopPropagation();
    });
    $(document).on('keyup', function (event) {
      var shouldDismissSearchPopup = event.which === 27 &&
        $('.search-popup').is(':visible');
      if (shouldDismissSearchPopup) {
        onPopupClose();
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    });
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  <script>
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      var $visitors = $(".leancloud_visitors");

      $visitors.each(function () {
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        .done(function (results) {
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            return;
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          for (var i = 0; i < results.length; i++) {
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