100 lines
7.5 KiB
HTML
100 lines
7.5 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>std::basic_streambuf<CharT,Traits>::pbump</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-cpp_io_basic_streambuf_pbump skin-cppreference2 action-view cpp-navbar">
|
|
<div id="cpp-content-base">
|
|
<div id="content"><a id="top"></a>
|
|
<h1 id="firstHeading" class="firstHeading"><span style="font-size:0.7em; line-height:130%">std::basic_streambuf<CharT,Traits>::</span>pbump</h1>
|
|
<div id="bodyContent">
|
|
<div id="contentSub"><span class="subpages">< <a href="cpp.html">cpp</a>‎ | <a href="cpp-io.html">io</a>‎ | <a href="cpp-io-basic_streambuf.html">basic streambuf</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-dcl">
|
|
<td class="t-dcl-nopad">
|
|
<div><span class="mw-geshi cpp source-cpp"><span class="kw4">void</span> pbump<span class="br0">(</span> <span class="kw4">int</span> count <span class="br0">)</span><span class="sy4">;</span></span></div>
|
|
</td>
|
|
<td class="t-dcl-nopad"></td>
|
|
<td class="t-dcl-nopad"></td>
|
|
</tr>
|
|
<tr class="t-dcl-sep">
|
|
<td></td>
|
|
<td></td>
|
|
<td></td>
|
|
</tr>
|
|
</tbody>
|
|
</table>
|
|
<p>重寻位<i>放置指针</i>（ <span class="t-lc"><a href="cpp-io-basic_streambuf-pptr.html">pptr()</a></span> ） <code>count</code> 个字符，其中 <code>count</code> 可为正或负。不对将指针移出放置区 <code>[pbase(), epptr())</code> 做检查。</p>
|
|
<p>若指针前进，然后调用 <span class="t-lc"><a href="cpp-io-basic_streambuf-overflow.html">overflow()</a></span> 冲入放置区到关联字符序列，则效果是输出拥有未定义值的额外 <code>count</code> 个字符。</p>
|
|
<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>count</td>
|
|
<td>-</td>
|
|
<td>加到放置指针的数</td>
|
|
</tr>
|
|
</table>
|
|
<h3><span class="mw-headline" id=".E8.BF.94.E5.9B.9E.E5.80.BC">返回值</span></h3>
|
|
<p>（无）</p>
|
|
<h3><span class="mw-headline" id=".E6.B3.A8.E6.84.8F">注意</span></h3>
|
|
<p>因为此函数接收 <code>int</code> ，故它无法操纵大于 <code>std::numeric_limits<int>::max()</code> 字符的缓冲区（ <a rel="nofollow" class="external text" href="http://wg21.link/lwg255">LWG 255</a> ）。</p>
|
|
<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="cpp source-cpp">
|
|
<pre class="de1"><span class="co2">#include <iostream></span>
|
|
<span class="co2">#include <string></span>
|
|
<span class="co2">#include <fstream></span>
|
|
|
|
<span class="kw1">struct</span> showput_streambuf <span class="sy4">:</span> <a href="cpp-io-basic_filebuf.html"><span class="kw1725">std::<span class="me2">filebuf</span></span></a>
|
|
<span class="br0">{</span>
|
|
<span class="kw1">using</span> std<span class="sy4">::</span><span class="me2">filebuf</span><span class="sy4">::</span><span class="me2">pbump</span><span class="sy4">;</span> <span class="co1">// 暴露受保护函数</span>
|
|
<a href="cpp-string-basic_string.html"><span class="kw1230">std::<span class="me2">string</span></span></a> showput<span class="br0">(</span><span class="br0">)</span> <span class="kw4">const</span> <span class="br0">{</span>
|
|
<span class="kw1">return</span> <a href="cpp-string-basic_string.html"><span class="kw1230">std::<span class="me2">string</span></span></a><span class="br0">(</span>pbase<span class="br0">(</span><span class="br0">)</span>, pptr<span class="br0">(</span><span class="br0">)</span><span class="br0">)</span><span class="sy4">;</span>
|
|
<span class="br0">}</span>
|
|
<span class="br0">}</span><span class="sy4">;</span>
|
|
|
|
<span class="kw4">int</span> main<span class="br0">(</span><span class="br0">)</span>
|
|
<span class="br0">{</span>
|
|
showput_streambuf mybuf<span class="sy4">;</span>
|
|
mybuf.<span class="me1">open</span><span class="br0">(</span><span class="st0">"test.txt"</span>, <a href="cpp-io-ios_base-openmode.html"><span class="kw1675">std::<span class="me2">ios_base</span><span class="sy4">::</span><span class="me2">out</span></span></a><span class="br0">)</span><span class="sy4">;</span>
|
|
<a href="cpp-io-basic_ostream.html"><span class="kw1729">std::<span class="me2">ostream</span></span></a> str<span class="br0">(</span><span class="sy3">&</span>mybuf<span class="br0">)</span><span class="sy4">;</span>
|
|
str <span class="sy1"><<</span> <span class="st0">"This is a test"</span> <span class="sy1"><<</span> <a href="cpp-io-manip-flush.html"><span class="kw1790">std::<span class="me2">flush</span></span></a> <span class="sy1"><<</span> <span class="st0">"1234"</span><span class="sy4">;</span>
|
|
<a href="cpp-io-cout.html"><span class="kw1758">std::<span class="me2">cout</span></span></a> <span class="sy1"><<</span> <span class="st0">"The put area contains: "</span> <span class="sy1"><<</span> mybuf.<span class="me1">showput</span><span class="br0">(</span><span class="br0">)</span> <span class="sy1"><<</span> <span class="st0">'<span class="es1">\n</span>'</span><span class="sy4">;</span>
|
|
mybuf.<span class="me1">pbump</span><span class="br0">(</span><span class="nu0">10</span><span class="br0">)</span><span class="sy4">;</span>
|
|
<a href="cpp-io-cout.html"><span class="kw1758">std::<span class="me2">cout</span></span></a> <span class="sy1"><<</span> <span class="st0">"after pbump(10), it contains "</span> <span class="sy1"><<</span> mybuf.<span class="me1">showput</span><span class="br0">(</span><span class="br0">)</span> <span class="sy1"><<</span> <span class="st0">'<span class="es1">\n</span>'</span><span class="sy4">;</span>
|
|
<span class="br0">}</span></pre></div>
|
|
</div>
|
|
<p>输出：</p>
|
|
<div dir="ltr" class="mw-geshi" style="text-align: left;">
|
|
<div class="text source-text">
|
|
<pre class="de1">The put area contains: 1234
|
|
after pbump(10), it contains 1234 is a test</pre></div>
|
|
</div>
|
|
</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="cpp-io-basic_streambuf-gbump.html"><span class="t-lines"><span>gbump</span></span></a></div>
|
|
</div>
|
|
</td>
|
|
<td>令输出序列中的下一位置指针前进<br />
|
|
<span class="t-mark">(受保护成员函数)</span></td>
|
|
</tr>
|
|
</table>
|
|
</div>
|
|
<div class="visualClear"></div>
|
|
</div>
|
|
</div>
|
|
</div>
|
|
</body>
|
|
</html>
|