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500 Internal Server Error<title><head> <body bgcolor="white"> <center><h1>500 Internal Server Error<h1><center> <hr><center>nginx<center> <body> <html> </a></h1> </div> <div class="entry-info" style="padding: 4px 0 0 0;"> <time class="entry-date published"> 发布于05月26日 </time> </div> <div class="intro mb20"> <p>功能<code>strdup()</code>和<code>strndup()</code>最终成为即将推出的C23标准:</p> <blockquote> <p><strong>7.24.6.4 The 100 function</strong></p> <p><strong>Synopsis</strong><br></p> <pre><code>#include <string.h> char *strdup(const char *s); </code></pre> <p><code>strdup</code>函数在分配的空间中创建<code>s</code>指向的字符串的副本，就像调用<code>malloc</code>一样.</p> <p><strong>Returns</strong><br></p> <p><strong>7.24.6.5 The 100 function</strong></p> <p><strong>Synopsis</strong><br></p> <pre><code>#include <string.h> char *strndup(const char *s, size_t size); </code></pre> <p><code>strndup</code>函数在分配的空间中创建一个字符串，该字符串使用<code>s</code>指向的数组的不超过<code>size</code>个初始字符初始化，直至第一个空字符(以先到者为准)，就像调用<code>malloc</code>一样.如果<code>s</code>所指向的数组在前<code>size</code>个字符内不包含null，则会将null附加到该数组的副本中.</p> <p><strong>Returns</strong><br></p> </blockquote> <p>为什么不考虑将POSIX-2008功能<code>strnlen</code>包括在内？</p> <pre><code>#include <string.h> size_t strnlen(const char *s, size_t maxlen); </code></pre> <p><code>strnlen()</code>函数应计算数组中<code>s</code>个指向的字节数(不包括终止NUL字符)或<code>maxlen</code>参数的值中的较小者.<code>strnlen()</code>函数不得判断<code>s</code>所指向的数组的<code>maxlen</code>个字节以上.</p> </div> </div> </div> <div class="q-single mt20"> <div class="intro mb20"> <div class="layui-card"> <div class="layui-card-header"><h2>推荐答案</h2></div> <div class="layui-card-body"> <p>有趣的是，这个函数是在<a href="https://www9.open-std.org/JTC1/SC22/WG14/www/docs/n2351.htm" rel="nofollow noreferrer">https://www9.open-std.org/JTC1/SC22/WG14/www/docs/n2351.htm</a>年提出的</p> <p>2019年伦敦会议讨论了这一问题.参见议程:</p> <p>讨论记录见<a href="https://www9.open-std.org/JTC1/SC22/WG14/www/docs/n2377.pdf" rel="nofollow noreferrer">https://www9.open-std.org/JTC1/SC22/WG14/www/docs/n2377.pdf</a>.</p> <p>由于没有达成共识，它被拒绝了.</p> <blockquote> <p>6.33 Sebor，将strnlen添加到C2X【N 2351】</p> <p>...</p> <p>*民意调查:N2351是否应投入C2X？</p> <p>(11/6/6)</p> <p>未达成明确共识.</p> </blockquote> <p>因此，未添加该函数.</p> </div> <div class="layui-card-footer"> <span id="share"></span> </div> </div> </div> </div> <div class="entry-content mt20"> <h2 class="tip_title">C++相关问答推荐</h2> <h3 class="geekgay layui-elip h11"><a href="https://www.learnfk.com/question/c++/78420691.html" title="try 使用libusb控制音量时LIBUSB_WRIGHT_PIPE">try 使用libusb控制音量时LIBUSB_WRIGHT_PIPE</a></h3> <h3 class="geekgay layui-elip h11"><a href="https://www.learnfk.com/question/c++/78385945.html" title="获取二维数组的最大元素">获取二维数组的最大元素</a></h3> <h3 class="geekgay layui-elip h11"><a href="https://www.learnfk.com/question/c++/78378970.html" title="为指针 struct 创建宏">为指针 struct 创建宏</a></h3> <h3 class="geekgay layui-elip 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