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<title>fread</title>
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<body class="mediawiki ltr sitedir-ltr ns-0 ns-subject page-c_io_fread skin-cppreference2 action-view cpp-navbar">
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<h1 id="firstHeading" class="firstHeading">fread</h1>
<div id="bodyContent">
<div id="contentSub"><span class="subpages">&lt; <a href="c.html">c</a>&lrm; | <a href="c-io.html">io</a></span></div>
<div id="mw-content-text" lang="zh" dir="ltr" class="mw-content-ltr" xml:lang="zh">
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<div>&#23450;&#20041;&#20110;&#22836;&#25991;&#20214; <code>&lt;stdio.h&gt;</code></div>
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<div><span class="mw-geshi c source-c"><a href="c-types-size_t.html"><span class="kw100">size_t</span></a> fread<span class="br0">(</span> <span class="kw4">void</span> &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;<span class="sy2">*</span>buffer, <a href="c-types-size_t.html"><span class="kw100">size_t</span></a> size, <a href="c-types-size_t.html"><span class="kw100">size_t</span></a> count,<br />
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; <a href="c-io.html"><span class="kw883">FILE</span></a> &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;<span class="sy2">*</span>stream <span class="br0">)</span><span class="sy4">;</span></span></div>
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<td class="t-dcl-nopad"></td>
<td><span class="t-mark-rev t-until-c99">(C99 &#21069;)</span></td>
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<div><span class="mw-geshi c source-c"><a href="c-types-size_t.html"><span class="kw100">size_t</span></a> fread<span class="br0">(</span> <span class="kw4">void</span> <span class="sy2">*</span><span class="kw4">restrict</span> buffer, <a href="c-types-size_t.html"><span class="kw100">size_t</span></a> size, <a href="c-types-size_t.html"><span class="kw100">size_t</span></a> count,<br />
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; <a href="c-io.html"><span class="kw883">FILE</span></a> <span class="sy2">*</span><span class="kw4">restrict</span> stream <span class="br0">)</span><span class="sy4">;</span></span></div>
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<td class="t-dcl-nopad"></td>
<td><span class="t-mark-rev t-since-c99">(C99 &#36215;)</span></td>
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<p>&#20174;&#32473;&#23450;&#36755;&#20837;&#27969; <code>stream</code> &#35835;&#21462;&#33267;&#22810; <code>count</code> &#20010;&#23545;&#35937;&#21040;&#25968;&#32452; <code>buffer</code> &#20013;&#65292;&#22914;&#21516;&#20197;&#23545;&#27599;&#20010;&#23545;&#35937;&#35843;&#29992; <code>size</code> &#27425; <span class="t-lc"><a href="c-io-fgetc.html">fgetc</a></span> &#65292;&#24182;&#25353;&#39034;&#24207;&#23384;&#20648;&#32467;&#26524;&#21040;&#36716;&#35793;&#20026; <span class="t-c"><span class="mw-geshi c source-c"><span class="kw4">unsigned</span> <span class="kw4">char</span></span></span> &#25968;&#32452;&#30340; <code>buffer</code> &#20013;&#30340;&#30456;&#32487;&#20301;&#32622;&#12290;&#27969;&#30340;&#25991;&#20214;&#20301;&#32622;&#25351;&#31034;&#22120;&#21069;&#36827;&#35835;&#21462;&#30340;&#23383;&#31526;&#25968;&#12290;</p>
<p>&#33509;&#20986;&#29616;&#38169;&#35823;&#65292;&#21017;&#27969;&#30340;&#25991;&#20214;&#20301;&#32622;&#25351;&#31034;&#22120;&#30340;&#32467;&#26524;&#20540;&#19981;&#30830;&#23450;&#12290;&#33509;&#35835;&#20837;&#37096;&#20998;&#30340;&#20803;&#32032;&#65292;&#21017;&#20803;&#32032;&#20540;&#19981;&#30830;&#23450;&#12290;</p>
<h3><span class="mw-headline" id=".E5.8F.82.E6.95.B0">&#21442;&#25968;</span></h3>
<table class="t-par-begin">
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<td>buffer</td>
<td>-</td>
<td>&#25351;&#21521;&#35201;&#35835;&#21462;&#30340;&#25968;&#32452;&#20013;&#39318;&#20010;&#23545;&#35937;&#30340;&#25351;&#38024;</td>
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<td>size</td>
<td>-</td>
<td>&#27599;&#20010;&#23545;&#35937;&#30340;&#23383;&#33410;&#22823;&#23567;</td>
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<tr class="t-par">
<td>count</td>
<td>-</td>
<td>&#35201;&#35835;&#21462;&#30340;&#23545;&#35937;&#25968;</td>
</tr>
<tr class="t-par">
<td>stream</td>
<td>-</td>
<td>&#35835;&#21462;&#26469;&#28304;&#30340;&#36755;&#20837;&#25991;&#20214;&#27969;</td>
</tr>
</table>
<h3><span class="mw-headline" id=".E8.BF.94.E5.9B.9E.E5.80.BC">&#36820;&#22238;&#20540;</span></h3>
<p>&#25104;&#21151;&#35835;&#21462;&#30340;&#23545;&#35937;&#25968;&#65292;&#33509;&#20986;&#29616;&#38169;&#35823;&#25110;&#25991;&#20214;&#23614;&#26465;&#20214;&#65292;&#21017;&#21487;&#33021;&#23567;&#20110; <code>count</code> &#12290;</p>
<p>&#33509; <code>size</code> &#25110; <code>count</code> &#20026;&#38646;&#65292;&#21017; <code>fread</code> &#36820;&#22238;&#38646;&#19988;&#19981;&#36827;&#34892;&#20854;&#20182;&#21160;&#20316;&#12290;</p>
<p><code>fread</code> &#19981;&#21306;&#21035;&#25991;&#20214;&#23614;&#21644;&#38169;&#35823;&#65292;&#32780;&#35843;&#29992;&#32773;&#24517;&#39035;&#29992; <span class="t-lc"><a href="c-io-feof.html">feof</a></span> &#21644; <span class="t-lc"><a href="c-io-ferror.html">ferror</a></span> &#37492;&#21035;&#20986;&#29616;&#32773;&#20026;&#20309;&#12290;</p>
<h3><span class="mw-headline" id=".E7.A4.BA.E4.BE.8B">&#31034;&#20363;</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 &lt;stdio.h&gt;</span>
<span class="kw2">enum</span> <span class="br0">{</span> SIZE <span class="sy1">=</span> <span class="nu0">5</span> <span class="br0">}</span><span class="sy4">;</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="kw4">double</span> a<span class="br0">[</span>SIZE<span class="br0">]</span> <span class="sy1">=</span> <span class="br0">{</span><span class="nu0">1</span>.,<span class="nu0">2</span>.,<span class="nu0">3</span>.,<span class="nu0">4</span>.,<span class="nu0">5</span>.<span class="br0">}</span><span class="sy4">;</span>
<a href="c-io.html"><span class="kw883">FILE</span></a> <span class="sy2">*</span>fp <span class="sy1">=</span> <a href="c-io-fopen.html"><span class="kw819">fopen</span></a><span class="br0">(</span><span class="st0">&quot;test.bin&quot;</span>, <span class="st0">&quot;wb&quot;</span><span class="br0">)</span><span class="sy4">;</span> <span class="co1">// &#24517;&#39035;&#29992;&#20108;&#36827;&#21046;&#27169;&#24335;</span>
<a href="c-io-fwrite.html"><span class="kw825">fwrite</span></a><span class="br0">(</span>a, <span class="kw4">sizeof</span> <span class="sy2">*</span>a, SIZE, fp<span class="br0">)</span><span class="sy4">;</span> <span class="co1">// &#20889; double &#30340;&#25968;&#32452;</span>
<a href="c-io-fclose.html"><span class="kw822">fclose</span></a><span class="br0">(</span>fp<span class="br0">)</span><span class="sy4">;</span>
<span class="kw4">double</span> b<span class="br0">[</span>SIZE<span class="br0">]</span><span class="sy4">;</span>
fp <span class="sy1">=</span> <a href="c-io-fopen.html"><span class="kw819">fopen</span></a><span class="br0">(</span><span class="st0">&quot;test.bin&quot;</span>,<span class="st0">&quot;rb&quot;</span><span class="br0">)</span><span class="sy4">;</span>
<a href="c-types-size_t.html"><span class="kw100">size_t</span></a> ret_code <span class="sy1">=</span> fread<span class="br0">(</span>b, <span class="kw4">sizeof</span> <span class="sy2">*</span>b, SIZE, fp<span class="br0">)</span><span class="sy4">;</span> <span class="co1">// &#35835; double &#30340;&#25968;&#32452;</span>
<span class="kw1">if</span><span class="br0">(</span>ret_code <span class="sy1">==</span> SIZE<span class="br0">)</span> <span class="br0">{</span>
<a href="c-io-puts.html"><span class="kw835">puts</span></a><span class="br0">(</span><span class="st0">&quot;Array read successfully, contents: &quot;</span><span class="br0">)</span><span class="sy4">;</span>
<span class="kw1">for</span><span class="br0">(</span><span class="kw4">int</span> n <span class="sy1">=</span> <span class="nu0">0</span><span class="sy4">;</span> n <span class="sy1">&lt;</span> SIZE<span class="sy4">;</span> <span class="sy2">++</span>n<span class="br0">)</span> <a href="c-io-fprintf.html"><span class="kw850">printf</span></a><span class="br0">(</span><span class="st0">&quot;%f &quot;</span>, b<span class="br0">[</span>n<span class="br0">]</span><span class="br0">)</span><span class="sy4">;</span>
<a href="c-io-putchar.html"><span class="kw834">putchar</span></a><span class="br0">(</span><span class="st0">&#39;<span class="es1">\n</span>&#39;</span><span class="br0">)</span><span class="sy4">;</span>
<span class="br0">}</span> <span class="kw1">else</span> <span class="br0">{</span> <span class="co1">// error handling</span>
<span class="kw1">if</span> <span class="br0">(</span><a href="c-io-feof.html"><span class="kw876">feof</span></a><span class="br0">(</span>fp<span class="br0">)</span><span class="br0">)</span>
<a href="c-io-fprintf.html"><span class="kw850">printf</span></a><span class="br0">(</span><span class="st0">&quot;Error reading test.bin: unexpected end of file<span class="es1">\n</span>&quot;</span><span class="br0">)</span><span class="sy4">;</span>
<span class="kw1">else</span> <span class="kw1">if</span> <span class="br0">(</span><a href="c-io-ferror.html"><span class="kw877">ferror</span></a><span class="br0">(</span>fp<span class="br0">)</span><span class="br0">)</span> <span class="br0">{</span>
<a href="c-io-perror.html"><span class="kw878">perror</span></a><span class="br0">(</span><span class="st0">&quot;Error reading test.bin&quot;</span><span class="br0">)</span><span class="sy4">;</span>
<span class="br0">}</span>
<span class="br0">}</span>
<a href="c-io-fclose.html"><span class="kw822">fclose</span></a><span class="br0">(</span>fp<span class="br0">)</span><span class="sy4">;</span>
<span class="br0">}</span></pre></div>
</div>
<p>&#36755;&#20986;&#65306;</p>
<div dir="ltr" class="mw-geshi" style="text-align: left;">
<div class="text source-text">
<pre class="de1">Array read successfully, contents:
1.000000 2.000000 3.000000 4.000000 5.000000</pre></div>
</div>
</div>
<h3><span class="mw-headline" id=".E5.BC.95.E7.94.A8">&#24341;&#29992;</span></h3>
<div class="t-ref-std-11">
<ul>
<li>C11 &#26631;&#20934;&#65288;ISO/IEC 9899:2011&#65289;&#65306;</li>
</ul>
<dl>
<dd>
<ul>
<li>7.21.8.1 The fread function (p: 335)</li>
</ul>
</dd>
</dl>
<div class="t-ref-std-c99">
<ul>
<li>C99 &#26631;&#20934;&#65288;ISO/IEC 9899:1999&#65289;&#65306;</li>
</ul>
<dl>
<dd>
<ul>
<li>7.19.8.1 The fread function (p: 301)</li>
</ul>
</dd>
</dl>
<div class="t-ref-std-c89">
<ul>
<li>C89/C90 &#26631;&#20934;&#65288;ISO/IEC 9899:1990&#65289;&#65306;</li>
</ul>
<dl>
<dd>
<ul>
<li>4.9.8.1 The fread function</li>
</ul>
</dd>
</dl>
</div>
<h3><span class="mw-headline" id=".E5.8F.82.E9.98.85">&#21442;&#38405;</span></h3>
<table class="t-dsc-begin">
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<div class="t-dsc-member-div">
<div><a href="c-io-fscanf.html"><span class="t-lines"><span>scanf</span><span>fscanf</span><span>sscanf</span><span>scanf_s</span><span>fscanf_s</span><span>sscanf_s</span></span></a></div>
<div><span class="t-lines"><span></span><span></span><span></span><span><span class="t-mark-rev t-since-c11">(C11)</span></span><span><span class="t-mark-rev t-since-c11">(C11)</span></span><span><span class="t-mark-rev t-since-c11">(C11)</span></span></span></div>
</div>
</td>
<td>&#20174;<span class="t-lc"><a href="c-io.html">stdin</a></span>&#12289;&#25991;&#20214;&#27969;&#25110;&#32531;&#20914;&#21306;&#35835;&#21462;&#26684;&#24335;&#21270;&#36755;&#20837;<br />
<span class="t-mark">(&#20989;&#25968;)</span></td>
</tr>
<tr class="t-dsc">
<td>
<div class="t-dsc-member-div">
<div><a href="c-io-fgets.html"><span class="t-lines"><span>fgets</span></span></a></div>
</div>
</td>
<td>&#20174;&#25991;&#20214;&#27969;&#33719;&#21462;&#19968;&#20010;&#23383;&#31526;&#20018;<br />
<span class="t-mark">(&#20989;&#25968;)</span></td>
</tr>
<tr class="t-dsc">
<td>
<div class="t-dsc-member-div">
<div><a href="c-io-fwrite.html"><span class="t-lines"><span>fwrite</span></span></a></div>
</div>
</td>
<td>&#20889;&#20837;&#21040;&#25991;&#20214;<br />
<span class="t-mark">(&#20989;&#25968;)</span></td>
</tr>
</table>
</div>
</div>
</div>
<div class="visualClear"></div>
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