60 lines
2.1 KiB
HTML
60 lines
2.1 KiB
HTML
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<!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="Petit FatFs" href="../00index_p.html">
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<link rel="stylesheet" href="../css_e.css" type="text/css" media="screen" title="ELM Default">
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<link rel="stylesheet" href="../css_p.css" type="text/css" media="screen" title="ELM Default">
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<title>Petit FatFs - disk_readp</title>
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</head>
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<body>
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<div class="para">
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<h2>disk_readp</h2>
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<p>The disk_readp function reads a partial sector of the device.</p>
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<pre>
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DRESULT disk_readp (
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BYTE* <span class="arg">buff</span>, <span class="c">/* [OUT] Pointer to the read buffer */</span>
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DWORD <span class="arg">sector</span>, <span class="c">/* [IN] Sector number */</span>
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UINT <span class="arg">offset</span>, <span class="c">/* [IN] Byte offset in the sector to start to read */</span>
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UINT <span class="arg">count</span> <span class="c">/* [IN] Number of bytes to read */</span>
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);
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</pre>
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</div>
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<div class="para">
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<h4>Parameters</h4>
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<dl class="par">
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<dt>buff</dt>
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<dd>Pointer to the read buffer to store the read data. If a NULL is given, read bytes will be forwarded to the outgoing stream instead of the memory.</dd>
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<dt>sector</dt>
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<dd>Specifies the sector number to be read in logical block address (LBA).</dd>
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<dt>offset</dt>
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<dd>Specifies the byte offset in the sector to start to read. The value can be 0 to 511.</dd>
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<dt>count</dt>
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<dd>Specifies number of bytes to read. The value can be 0 to 512 and <tt class="arg">offset</tt> + <tt class="arg">count</tt> must not exceed 512.</dd>
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</dl>
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</div>
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<div class="para">
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<h4>Return Value</h4>
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<dl class="ret">
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<dt>RES_OK (0)</dt>
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<dd>The function succeeded.</dd>
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<dt>RES_ERROR</dt>
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<dd>Any hard error occured during the disk read operation and could not recover it.</dd>
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<dt>RES_PARERR</dt>
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<dd>Invalid parameter.</dd>
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<dt>RES_NOTRDY</dt>
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<dd>The device has not been initialized.</dd>
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</dl>
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</div>
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<p class="foot"><a href="../00index_p.html">Return</a></p>
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</body>
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</html>
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