savelij13
5fa1073a5a
- Fast seek feature is also applied to f_read() and f_write(). - f_lseek() reports required table size on creating CLMP. - Extended format syntax of f_printf function. - Ignores duplicated directory separators in given path names.
75 lines
2.4 KiB
HTML
75 lines
2.4 KiB
HTML
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">
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<html lang="en">
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<head>
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<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
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<meta http-equiv="Content-Style-Type" content="text/css">
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<link rel="up" title="FatFs" href="../00index_e.html">
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<link rel="alternate" hreflang="ja" title="Japanese" href="../ja/read.html">
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<link rel="stylesheet" href="../css_e.css" type="text/css" media="screen" title="ELM Default">
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<title>FatFs - f_read</title>
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</head>
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<body>
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<div class="para func">
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<h2>f_read</h2>
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<p>The f_read function reads data from a file.</p>
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<pre>
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FRESULT f_read (
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FIL* <em>FileObject</em>, <span class="c">/* Pointer to the file object structure */</span>
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void* <em>Buffer</em>, <span class="c">/* Pointer to the buffer to store read data */</span>
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UINT <em>ByteToRead</em>, <span class="c">/* Number of bytes to read */</span>
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UINT* <em>ByteRead</em> <span class="c">/* Pointer to the variable to return number of bytes read */</span>
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);
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</pre>
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</div>
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<div class="para arg">
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<h4>Parameters</h4>
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<dl class="par">
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<dt>FileObject</dt>
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<dd>Pointer to the open file object.</dd>
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<dt>Buffer</dt>
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<dd>Pointer to the buffer to store read data</dd>
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<dt>ByteToRead</dt>
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<dd>Number of bytes to read in range of UINT.</dd>
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<dt>ByteRead</dt>
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<dd>Pointer to the UINT variable to return number of bytes read. The value is always valid after the function call regardless of the result.</dd>
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</dl>
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</div>
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<div class="para ret">
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<h4>Return Values</h4>
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<p>
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<a href="rc.html#ok">FR_OK</a>,
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<a href="rc.html#de">FR_DISK_ERR</a>,
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<a href="rc.html#ie">FR_INT_ERR</a>,
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<a href="rc.html#nr">FR_NOT_READY</a>,
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<a href="rc.html#io">FR_INVALID_OBJECT</a>,
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<a href="rc.html#tm">FR_TIMEOUT</a>
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</p>
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</div>
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<div class="para desc">
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<h4>Description</h4>
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<p>The file pointer of the file object increases in number of bytes read. After the function succeeded, <tt>*ByteRead</tt> should be checked to detect the end of file. In case of <tt>*ByteRead < ByteToRead</tt>, it means the read/write pointer reached end of the file during read operation.</p>
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</div>
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<div class="para comp">
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<h4>QuickInfo</h4>
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<p>Always available.</p>
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</div>
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<div class="para ref">
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<h4>See Also</h4>
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<p><tt><a href="open.html">f_open</a>, <a href="gets.html">fgets</a>, <a href="write.html">f_write</a>, <a href="close.html">f_close</a>, <a href="sfile.html">FIL</a></tt></p>
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</div>
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<p class="foot"><a href="../00index_e.html">Return</a></p>
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</body>
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</html>
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