394 lines
25 KiB
HTML
394 lines
25 KiB
HTML
<!DOCTYPE html>
|
|
<html lang="zh" dir="ltr" class="client-nojs" xmlns="http://www.w3.org/1999/xhtml" xml:lang="zh">
|
|
<head><meta http-equiv="x-ua-compatible" content="ie=edge">
|
|
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
|
|
<title>round, roundf, roundl, lround, lroundf, lroundl, llround, llroundf, llroundl</title>
|
|
<link rel="stylesheet" href="ext.css" />
|
|
<link rel="stylesheet" href="site_modules.css" />
|
|
</head>
|
|
<body class="mediawiki ltr sitedir-ltr ns-0 ns-subject page-c_numeric_math_round skin-cppreference2 action-view cpp-navbar">
|
|
<div id="cpp-content-base">
|
|
<div id="content"><a id="top"></a>
|
|
<h1 id="firstHeading" class="firstHeading">round, roundf, roundl, lround, lroundf, lroundl, llround, llroundf, llroundl</h1>
|
|
<div id="bodyContent">
|
|
<div id="contentSub"><span class="subpages">< <a href="c.html">c</a>‎ | <a href="c-numeric.html">numeric</a>‎ | <a href="c-numeric-math.html">math</a></span></div>
|
|
<div id="mw-content-text" lang="zh" dir="ltr" class="mw-content-ltr" xml:lang="zh">
|
|
<table class="t-dcl-begin">
|
|
<tbody>
|
|
<tr class="t-dsc-header">
|
|
<td>
|
|
<div>定义于头文件 <code><math.h></code></div>
|
|
</td>
|
|
<td></td>
|
|
<td></td>
|
|
</tr>
|
|
<tr class="t-dcl t-since-c99">
|
|
<td>
|
|
<div><span class="mw-geshi c source-c"><span class="kw4">float</span> roundf<span class="br0">(</span> <span class="kw4">float</span> arg <span class="br0">)</span><span class="sy4">;</span></span></div>
|
|
</td>
|
|
<td>(1)</td>
|
|
<td><span class="t-mark-rev t-since-c99">(C99 起)</span></td>
|
|
</tr>
|
|
<tr class="t-dcl t-since-c99">
|
|
<td>
|
|
<div><span class="mw-geshi c source-c"><span class="kw4">double</span> round<span class="br0">(</span> <span class="kw4">double</span> arg <span class="br0">)</span><span class="sy4">;</span></span></div>
|
|
</td>
|
|
<td>(2)</td>
|
|
<td><span class="t-mark-rev t-since-c99">(C99 起)</span></td>
|
|
</tr>
|
|
<tr class="t-dcl t-since-c99">
|
|
<td>
|
|
<div><span class="mw-geshi c source-c"><span class="kw4">long</span> <span class="kw4">double</span> roundl<span class="br0">(</span> <span class="kw4">long</span> <span class="kw4">double</span> arg <span class="br0">)</span><span class="sy4">;</span></span></div>
|
|
</td>
|
|
<td>(3)</td>
|
|
<td><span class="t-mark-rev t-since-c99">(C99 起)</span></td>
|
|
</tr>
|
|
<tr class="t-dsc-header">
|
|
<td>
|
|
<div>定义于头文件 <code><tgmath.h></code></div>
|
|
</td>
|
|
<td></td>
|
|
<td></td>
|
|
</tr>
|
|
<tr class="t-dcl t-since-c99">
|
|
<td>
|
|
<div><span class="mw-geshi c source-c"><span class="co2">#define round( arg )</span></span></div>
|
|
</td>
|
|
<td>(4)</td>
|
|
<td><span class="t-mark-rev t-since-c99">(C99 起)</span></td>
|
|
</tr>
|
|
<tr class="t-dsc-header">
|
|
<td>
|
|
<div>定义于头文件 <code><math.h></code></div>
|
|
</td>
|
|
<td></td>
|
|
<td></td>
|
|
</tr>
|
|
<tr class="t-dcl t-since-c99">
|
|
<td>
|
|
<div><span class="mw-geshi c source-c"><span class="kw4">long</span> lroundf<span class="br0">(</span> <span class="kw4">float</span> arg <span class="br0">)</span><span class="sy4">;</span></span></div>
|
|
</td>
|
|
<td>(5)</td>
|
|
<td><span class="t-mark-rev t-since-c99">(C99 起)</span></td>
|
|
</tr>
|
|
<tr class="t-dcl t-since-c99">
|
|
<td>
|
|
<div><span class="mw-geshi c source-c"><span class="kw4">long</span> lround<span class="br0">(</span> <span class="kw4">double</span> arg <span class="br0">)</span><span class="sy4">;</span></span></div>
|
|
</td>
|
|
<td>(6)</td>
|
|
<td><span class="t-mark-rev t-since-c99">(C99 起)</span></td>
|
|
</tr>
|
|
<tr class="t-dcl t-since-c99">
|
|
<td>
|
|
<div><span class="mw-geshi c source-c"><span class="kw4">long</span> lroundl<span class="br0">(</span> <span class="kw4">long</span> <span class="kw4">double</span> arg <span class="br0">)</span><span class="sy4">;</span></span></div>
|
|
</td>
|
|
<td>(7)</td>
|
|
<td><span class="t-mark-rev t-since-c99">(C99 起)</span></td>
|
|
</tr>
|
|
<tr class="t-dsc-header">
|
|
<td>
|
|
<div>定义于头文件 <code><tgmath.h></code></div>
|
|
</td>
|
|
<td></td>
|
|
<td></td>
|
|
</tr>
|
|
<tr class="t-dcl t-since-c99">
|
|
<td>
|
|
<div><span class="mw-geshi c source-c"><span class="co2">#define lround( arg )</span></span></div>
|
|
</td>
|
|
<td>(8)</td>
|
|
<td><span class="t-mark-rev t-since-c99">(C99 起)</span></td>
|
|
</tr>
|
|
<tr class="t-dsc-header">
|
|
<td>
|
|
<div>定义于头文件 <code><math.h></code></div>
|
|
</td>
|
|
<td></td>
|
|
<td></td>
|
|
</tr>
|
|
<tr class="t-dcl t-since-c99">
|
|
<td>
|
|
<div><span class="mw-geshi c source-c"><span class="kw4">long</span> <span class="kw4">long</span> llroundf<span class="br0">(</span> <span class="kw4">float</span> arg <span class="br0">)</span><span class="sy4">;</span></span></div>
|
|
</td>
|
|
<td>(9)</td>
|
|
<td><span class="t-mark-rev t-since-c99">(C99 起)</span></td>
|
|
</tr>
|
|
<tr class="t-dcl t-since-c99">
|
|
<td>
|
|
<div><span class="mw-geshi c source-c"><span class="kw4">long</span> <span class="kw4">long</span> llround<span class="br0">(</span> <span class="kw4">double</span> arg <span class="br0">)</span><span class="sy4">;</span></span></div>
|
|
</td>
|
|
<td>(10)</td>
|
|
<td><span class="t-mark-rev t-since-c99">(C99 起)</span></td>
|
|
</tr>
|
|
<tr class="t-dcl t-since-c99">
|
|
<td>
|
|
<div><span class="mw-geshi c source-c"><span class="kw4">long</span> <span class="kw4">long</span> llroundl<span class="br0">(</span> <span class="kw4">long</span> <span class="kw4">double</span> arg <span class="br0">)</span><span class="sy4">;</span></span></div>
|
|
</td>
|
|
<td>(11)</td>
|
|
<td><span class="t-mark-rev t-since-c99">(C99 起)</span></td>
|
|
</tr>
|
|
<tr class="t-dsc-header">
|
|
<td>
|
|
<div>定义于头文件 <code><tgmath.h></code></div>
|
|
</td>
|
|
<td></td>
|
|
<td></td>
|
|
</tr>
|
|
<tr class="t-dcl t-since-c99">
|
|
<td>
|
|
<div><span class="mw-geshi c source-c"><span class="co2">#define llround( arg )</span></span></div>
|
|
</td>
|
|
<td>(12)</td>
|
|
<td><span class="t-mark-rev t-since-c99">(C99 起)</span></td>
|
|
</tr>
|
|
<tr class="t-dcl-sep">
|
|
<td></td>
|
|
<td></td>
|
|
<td></td>
|
|
</tr>
|
|
</tbody>
|
|
</table>
|
|
<div class="t-li1"><span class="t-li">1-3)</span> 计算与 <code>arg</code> 最邻近的整数值（以浮点格式），中点情况取远离零者，无关乎当前舍入模式。</div>
|
|
<div class="t-li1"><span class="t-li">5-7, 9-11)</span> 计算与 <code>arg</code> 最邻近的整数值（以整数格式），中点情况取远离零者，无关乎当前舍入模式。</div>
|
|
<div class="t-li1"><span class="t-li">4,8,12)</span> 泛型宏：若 <code>arg</code> 拥有 <span class="t-c"><span class="mw-geshi c source-c"><span class="kw4">long</span> <span class="kw4">double</span></span></span> 类型，则分别调用 <code>roundl</code> 、 <code>lroundl</code> 、 <code>llroundl</code> 。否则，若 <code>arg</code> 拥有整数类型或 <span class="t-c"><span class="mw-geshi c source-c"><span class="kw4">double</span></span></span> 类型，则分别调用 <code>round</code> 、 <code>lround</code> 、 <code>llround</code> 。否则分别调用 <code>roundf</code>, <code>lroundf</code>, <code>llroundf</code> 。</div>
|
|
<h3><span class="mw-headline" id=".E5.8F.82.E6.95.B0">参数</span></h3>
|
|
<table class="t-par-begin">
|
|
<tr class="t-par">
|
|
<td>arg</td>
|
|
<td>-</td>
|
|
<td>浮点值</td>
|
|
</tr>
|
|
</table>
|
|
<h3><span class="mw-headline" id=".E8.BF.94.E5.9B.9E.E5.80.BC">返回值</span></h3>
|
|
<p>若不出现错误，则与返回 <code>arg</code> 的最邻近整数值，中点情况取远离零者，</p>
|
|
<div class="t-plot">
|
|
<div class="t-plot-left">返回值</div>
|
|
<div class="t-plot-image-left"><img alt="math-round away zero.svg" src="math-round_away_zero.svg" width="200" height="200" /></div>
|
|
<div class="t-plot-bottom">参数</div>
|
|
</div>
|
|
<p>若出现定义域错误，则返回实现定义值。</p>
|
|
<h3><span class="mw-headline" id=".E9.94.99.E8.AF.AF.E5.A4.84.E7.90.86">错误处理</span></h3>
|
|
<p>报告 <a href="c-numeric-math-math_errhandling.html">math_errhandling</a> 中指定的错误。</p>
|
|
<p>若 <code>lround</code> 或 <code>llround</code> 的结果在返回类型的可表示范围外，则可能出现定义域错误或值域错误。</p>
|
|
<p>若实现支持 IEEE 浮点算术（ IEC 60559 ），</p>
|
|
<dl>
|
|
<dd>对于 <code>round</code> 、 <code>roundf</code> 及 <code>roundl</code> 函数：</dd>
|
|
</dl>
|
|
<ul>
|
|
<li>当前<a href="c-numeric-fenv-FE_round.html">舍入模式</a>无效。</li>
|
|
<li>若 <code>arg</code> 为 ±∞ ，则返回不修改的该值</li>
|
|
<li>若 <code>arg</code> 为 ±0 ，则返回不修改的该值</li>
|
|
<li>若 <code>arg</code> 为 NaN ，则返回 NaN</li>
|
|
</ul>
|
|
<dl>
|
|
<dd>对于 <code>lround</code> 与 <code>llround</code> 函数族：</dd>
|
|
</dl>
|
|
<ul>
|
|
<li>决不引发 <span class="t-lc"><a href="c-numeric-fenv-FE_exceptions.html">FE_INEXACT</a></span></li>
|
|
<li>当前<a href="c-numeric-fenv-FE_round.html">舍入模式</a>无效。</li>
|
|
<li>若 <code>arg</code> 为 ±∞ ，则引发 <span class="t-lc"><a href="c-numeric-fenv-FE_exceptions.html">FE_INVALID</a></span> 并返回实现定义值</li>
|
|
<li>若舍入结果在返回类型的范围外，则引发 <span class="t-lc"><a href="c-numeric-fenv-FE_exceptions.html">FE_INVALID</a></span> 并返回实现定义值</li>
|
|
<li>若 <code>arg</code> 为 NaN ，则引发 <span class="t-lc"><a href="c-numeric-fenv-FE_exceptions.html">FE_INVALID</a></span> 并返回实现定义值</li>
|
|
</ul>
|
|
<h3><span class="mw-headline" id=".E6.B3.A8.E6.84.8F">注意</span></h3>
|
|
<p><code>round</code> 在舍入非整数有限值时，可以（但不要求）引发 <span class="t-lc"><a href="c-numeric-fenv-FE_exceptions.html">FE_INEXACT</a></span> 。</p>
|
|
<p>所有标准浮点格式中，最大可表示浮点值均为准确的整数，故 <code>round</code> 自身决不上溢；然而在存储于整数对象时，结果可能溢出任何整数类型（包含 <span class="t-lc"><a href="c-types-integer.html">intmax_t</a></span> ）。</p>
|
|
<p><a rel="nofollow" class="external text" href="http://pubs.opengroup.org/onlinepubs/9699919799/functions/lround.html">POSIX 指定</a> <code>lround</code> 或 <code>llround</code> 引发 <span class="t-lc"><a href="c-numeric-fenv-FE_exceptions.html">FE_INEXACT</a></span> 的所有情况都是定义域错误。</p>
|
|
<p><code>round</code> 的 <span class="t-c"><span class="mw-geshi c source-c"><span class="kw4">double</span></span></span> 版本如同实现如下：</p>
|
|
<div dir="ltr" class="mw-geshi" style="text-align: left;">
|
|
<div class="c source-c">
|
|
<pre class="de1"><span class="co2">#include <math.h></span>
|
|
<span class="co2">#include <fenv.h></span>
|
|
<span class="co2">#pragma STDC FENV_ACCESS ON</span>
|
|
<span class="kw4">double</span> round<span class="br0">(</span><span class="kw4">double</span> x<span class="br0">)</span>
|
|
<span class="br0">{</span>
|
|
fenv_t save_env<span class="sy4">;</span>
|
|
<a href="c-numeric-fenv-feholdexcept.html"><span class="kw724">feholdexcept</span></a><span class="br0">(</span><span class="sy3">&</span>save_env<span class="br0">)</span><span class="sy4">;</span>
|
|
<span class="kw4">double</span> result <span class="sy1">=</span> <a href="c-numeric-math-rint.html"><span class="kw690">rint</span></a><span class="br0">(</span>x<span class="br0">)</span><span class="sy4">;</span>
|
|
<span class="kw1">if</span> <span class="br0">(</span><a href="c-numeric-fenv-fetestexcept.html"><span class="kw716">fetestexcept</span></a><span class="br0">(</span><a href="c-numeric-fenv-FE_exceptions.html"><span class="kw728">FE_INEXACT</span></a><span class="br0">)</span><span class="br0">)</span> <span class="br0">{</span>
|
|
<a href="c-numeric-fenv-feround.html"><span class="kw721">fesetround</span></a><span class="br0">(</span><a href="c-numeric-fenv-FE_round.html"><span class="kw734">FE_TOWARDZERO</span></a><span class="br0">)</span><span class="sy4">;</span>
|
|
result <span class="sy1">=</span> <a href="c-numeric-math-rint.html"><span class="kw690">rint</span></a><span class="br0">(</span><a href="c-numeric-math-copysign.html"><span class="kw700">copysign</span></a><span class="br0">(</span><span class="nu16">0.5</span> <span class="sy2">+</span> <a href="c-numeric-math-fabs.html"><span class="kw644">fabs</span></a><span class="br0">(</span>x<span class="br0">)</span>, x<span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
|
|
<span class="br0">}</span>
|
|
<a href="c-numeric-fenv-feupdateenv.html"><span class="kw725">feupdateenv</span></a><span class="br0">(</span><span class="sy3">&</span>save_env<span class="br0">)</span><span class="sy4">;</span>
|
|
<span class="kw1">return</span> result<span class="sy4">;</span>
|
|
<span class="br0">}</span></pre></div>
|
|
</div>
|
|
<h3><span class="mw-headline" id=".E7.A4.BA.E4.BE.8B">示例</span></h3>
|
|
<div class="t-example">
|
|
<div class="t-example-live-link"></div>
|
|
<div dir="ltr" class="mw-geshi" style="text-align: left;">
|
|
<div class="c source-c">
|
|
<pre class="de1"><span class="co2">#include <stdio.h></span>
|
|
<span class="co2">#include <math.h></span>
|
|
<span class="co2">#include <fenv.h></span>
|
|
<span class="co2">#include <limits.h></span>
|
|
|
|
<span class="co2">#pragma STDC FENV_ACCESS ON</span>
|
|
|
|
<span class="kw4">int</span> main<span class="br0">(</span><span class="kw4">void</span><span class="br0">)</span>
|
|
<span class="br0">{</span>
|
|
<span class="co1">// round</span>
|
|
<a href="c-io-fprintf.html"><span class="kw848">printf</span></a><span class="br0">(</span><span class="st0">"round(+2.3) = %+.1f "</span>, round<span class="br0">(</span><span class="nu16">2.3</span><span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
|
|
<a href="c-io-fprintf.html"><span class="kw848">printf</span></a><span class="br0">(</span><span class="st0">"round(+2.5) = %+.1f "</span>, round<span class="br0">(</span><span class="nu16">2.5</span><span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
|
|
<a href="c-io-fprintf.html"><span class="kw848">printf</span></a><span class="br0">(</span><span class="st0">"round(+2.7) = %+.1f<span class="es1">\n</span>"</span>, round<span class="br0">(</span><span class="nu16">2.7</span><span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
|
|
<a href="c-io-fprintf.html"><span class="kw848">printf</span></a><span class="br0">(</span><span class="st0">"round(-2.3) = %+.1f "</span>, round<span class="br0">(</span><span class="sy2">-</span><span class="nu16">2.3</span><span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
|
|
<a href="c-io-fprintf.html"><span class="kw848">printf</span></a><span class="br0">(</span><span class="st0">"round(-2.5) = %+.1f "</span>, round<span class="br0">(</span><span class="sy2">-</span><span class="nu16">2.5</span><span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
|
|
<a href="c-io-fprintf.html"><span class="kw848">printf</span></a><span class="br0">(</span><span class="st0">"round(-2.7) = %+.1f<span class="es1">\n</span>"</span>, round<span class="br0">(</span><span class="sy2">-</span><span class="nu16">2.7</span><span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
|
|
|
|
<a href="c-io-fprintf.html"><span class="kw848">printf</span></a><span class="br0">(</span><span class="st0">"round(-0.0) = %+.1f<span class="es1">\n</span>"</span>, round<span class="br0">(</span><span class="sy2">-</span><span class="nu16">0.0</span><span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
|
|
<a href="c-io-fprintf.html"><span class="kw848">printf</span></a><span class="br0">(</span><span class="st0">"round(-Inf) = %+f<span class="es1">\n</span>"</span>, round<span class="br0">(</span><span class="sy2">-</span>INFINITY<span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
|
|
|
|
<span class="co1">// lround</span>
|
|
<a href="c-io-fprintf.html"><span class="kw848">printf</span></a><span class="br0">(</span><span class="st0">"lround(+2.3) = %ld "</span>, lround<span class="br0">(</span><span class="nu16">2.3</span><span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
|
|
<a href="c-io-fprintf.html"><span class="kw848">printf</span></a><span class="br0">(</span><span class="st0">"lround(+2.5) = %ld "</span>, lround<span class="br0">(</span><span class="nu16">2.5</span><span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
|
|
<a href="c-io-fprintf.html"><span class="kw848">printf</span></a><span class="br0">(</span><span class="st0">"lround(+2.7) = %ld<span class="es1">\n</span>"</span>, lround<span class="br0">(</span><span class="nu16">2.7</span><span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
|
|
<a href="c-io-fprintf.html"><span class="kw848">printf</span></a><span class="br0">(</span><span class="st0">"lround(-2.3) = %ld "</span>, lround<span class="br0">(</span><span class="sy2">-</span><span class="nu16">2.3</span><span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
|
|
<a href="c-io-fprintf.html"><span class="kw848">printf</span></a><span class="br0">(</span><span class="st0">"lround(-2.5) = %ld "</span>, lround<span class="br0">(</span><span class="sy2">-</span><span class="nu16">2.5</span><span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
|
|
<a href="c-io-fprintf.html"><span class="kw848">printf</span></a><span class="br0">(</span><span class="st0">"lround(-2.7) = %ld<span class="es1">\n</span>"</span>, lround<span class="br0">(</span><span class="sy2">-</span><span class="nu16">2.7</span><span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
|
|
|
|
<a href="c-io-fprintf.html"><span class="kw848">printf</span></a><span class="br0">(</span><span class="st0">"lround(-0.0) = %ld<span class="es1">\n</span>"</span>, lround<span class="br0">(</span><span class="sy2">-</span><span class="nu16">0.0</span><span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
|
|
<a href="c-io-fprintf.html"><span class="kw848">printf</span></a><span class="br0">(</span><span class="st0">"lround(-Inf) = %ld<span class="es1">\n</span>"</span>, lround<span class="br0">(</span><span class="sy2">-</span>INFINITY<span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span> <span class="co1">// FE_INVALID 引发</span>
|
|
|
|
<span class="co1">// 错误处理</span>
|
|
<a href="c-numeric-fenv-feclearexcept.html"><span class="kw715">feclearexcept</span></a><span class="br0">(</span><a href="c-numeric-fenv-FE_exceptions.html"><span class="kw726">FE_ALL_EXCEPT</span></a><span class="br0">)</span><span class="sy4">;</span>
|
|
<a href="c-io-fprintf.html"><span class="kw848">printf</span></a><span class="br0">(</span><span class="st0">"lround(LONG_MAX+1.5) = %ld<span class="es1">\n</span>"</span>, lround<span class="br0">(</span><a href="c-types-limits.html"><span class="kw365">LONG_MAX</span></a><span class="sy2">+</span><span class="nu16">1.5</span><span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
|
|
<span class="kw1">if</span><span class="br0">(</span><a href="c-numeric-fenv-fetestexcept.html"><span class="kw716">fetestexcept</span></a><span class="br0">(</span><a href="c-numeric-fenv-FE_exceptions.html"><span class="kw729">FE_INVALID</span></a><span class="br0">)</span><span class="br0">)</span> <a href="c-io-puts.html"><span class="kw833">puts</span></a><span class="br0">(</span><span class="st0">" FE_INVALID was raised"</span><span class="br0">)</span><span class="sy4">;</span>
|
|
<span class="br0">}</span></pre></div>
|
|
</div>
|
|
<p>可能的输出：</p>
|
|
<div dir="ltr" class="mw-geshi" style="text-align: left;">
|
|
<div class="text source-text">
|
|
<pre class="de1">round(+2.3) = +2.0 round(+2.5) = +3.0 round(+2.7) = +3.0
|
|
round(-2.3) = -2.0 round(-2.5) = -3.0 round(-2.7) = -3.0
|
|
round(-0.0) = -0.0
|
|
round(-Inf) = -inf
|
|
lround(+2.3) = 2 lround(+2.5) = 3 lround(+2.7) = 3
|
|
lround(-2.3) = -2 lround(-2.5) = -3 lround(-2.7) = -3
|
|
lround(-0.0) = 0
|
|
lround(-Inf) = -9223372036854775808
|
|
lround(LONG_MAX+1.5) = -9223372036854775808
|
|
FE_INVALID was raised</pre></div>
|
|
</div>
|
|
</div>
|
|
<h3><span class="mw-headline" id=".E5.BC.95.E7.94.A8">引用</span></h3>
|
|
<div class="t-ref-std-11">
|
|
<ul>
|
|
<li>C11 标准（ISO/IEC 9899:2011）：</li>
|
|
</ul>
|
|
<dl>
|
|
<dd>
|
|
<ul>
|
|
<li>7.12.9.6 The round functions (p: 253)</li>
|
|
</ul>
|
|
</dd>
|
|
</dl>
|
|
<dl>
|
|
<dd>
|
|
<ul>
|
|
<li>7.12.9.7 The lround and llround functions (p: 253)</li>
|
|
</ul>
|
|
</dd>
|
|
</dl>
|
|
<dl>
|
|
<dd>
|
|
<ul>
|
|
<li>7.25 Type-generic math <tgmath.h> (p: 373-375)</li>
|
|
</ul>
|
|
</dd>
|
|
</dl>
|
|
<dl>
|
|
<dd>
|
|
<ul>
|
|
<li>F.10.6.6 The round functions (p: 527)</li>
|
|
</ul>
|
|
</dd>
|
|
</dl>
|
|
<dl>
|
|
<dd>
|
|
<ul>
|
|
<li>F.10.6.7 The lround and llround functions (p: 528)</li>
|
|
</ul>
|
|
</dd>
|
|
</dl>
|
|
<div class="t-ref-std-c99">
|
|
<ul>
|
|
<li>C99 标准（ISO/IEC 9899:1999）：</li>
|
|
</ul>
|
|
<dl>
|
|
<dd>
|
|
<ul>
|
|
<li>7.12.9.6 The round functions (p: 233)</li>
|
|
</ul>
|
|
</dd>
|
|
</dl>
|
|
<dl>
|
|
<dd>
|
|
<ul>
|
|
<li>7.12.9.7 The lround and llround functions (p: 234)</li>
|
|
</ul>
|
|
</dd>
|
|
</dl>
|
|
<dl>
|
|
<dd>
|
|
<ul>
|
|
<li>7.22 Type-generic math <tgmath.h> (p: 335-337)</li>
|
|
</ul>
|
|
</dd>
|
|
</dl>
|
|
<dl>
|
|
<dd>
|
|
<ul>
|
|
<li>F.9.6.6 The round functions (p: 464)</li>
|
|
</ul>
|
|
</dd>
|
|
</dl>
|
|
<dl>
|
|
<dd>
|
|
<ul>
|
|
<li>F.9.6.7 The lround and llround functions (p: 464)</li>
|
|
</ul>
|
|
</dd>
|
|
</dl>
|
|
</div>
|
|
<h3><span class="mw-headline" id=".E5.8F.82.E9.98.85">参阅</span></h3>
|
|
<table class="t-dsc-begin">
|
|
<tr class="t-dsc">
|
|
<td>
|
|
<div class="t-dsc-member-div">
|
|
<div><a href="c-numeric-math-floor.html"><span class="t-lines"><span>floor</span><span>floorf</span><span>floorl</span></span></a></div>
|
|
<div><span class="t-lines"><span></span><span><span class="t-mark-rev t-since-c99">(C99)</span></span><span><span class="t-mark-rev t-since-c99">(C99)</span></span></span></div>
|
|
</div>
|
|
</td>
|
|
<td>计算不大于给定值的最大整数<br />
|
|
<span class="t-mark">(函数)</span></td>
|
|
</tr>
|
|
<tr class="t-dsc">
|
|
<td>
|
|
<div class="t-dsc-member-div">
|
|
<div><a href="c-numeric-math-ceil.html"><span class="t-lines"><span>ceil</span><span>ceilf</span><span>ceill</span></span></a></div>
|
|
<div><span class="t-lines"><span></span><span><span class="t-mark-rev t-since-c99">(C99)</span></span><span><span class="t-mark-rev t-since-c99">(C99)</span></span></span></div>
|
|
</div>
|
|
</td>
|
|
<td>计算不小于给定值的最小整数<br />
|
|
<span class="t-mark">(函数)</span></td>
|
|
</tr>
|
|
<tr class="t-dsc">
|
|
<td>
|
|
<div class="t-dsc-member-div">
|
|
<div><a href="c-numeric-math-trunc.html"><span class="t-lines"><span>trunc</span><span>truncf</span><span>truncl</span></span></a></div>
|
|
<div><span class="t-lines"><span><span class="t-mark-rev t-since-c99">(C99)</span></span><span><span class="t-mark-rev t-since-c99">(C99)</span></span><span><span class="t-mark-rev t-since-c99">(C99)</span></span></span></div>
|
|
</div>
|
|
</td>
|
|
<td>取整到绝对值不大于给定值的最接近整数<br />
|
|
<span class="t-mark">(函数)</span></td>
|
|
</tr>
|
|
</table>
|
|
</div>
|
|
</div>
|
|
<div class="visualClear"></div>
|
|
</div>
|
|
</div>
|
|
</div>
|
|
</body>
|
|
</html>
|