<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd"> <html lang="en"> <head> <meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1"> <meta http-equiv="Content-Style-Type" content="text/css"> <link rel="up" title="FatFs" href="../00index_e.html"> <link rel="alternate" hreflang="ja" title="Japanese" href="../ja/read.html"> <link rel="stylesheet" href="../css_e.css" type="text/css" media="screen" title="ELM Default"> <title>FatFs - f_read</title> </head> <body> <div class="para func"> <h2>f_read</h2> <p>The f_read function reads data from a file.</p> <pre> FRESULT f_read ( FIL* <span class="arg">fp</span>, <span class="c">/* [IN] File object */</span> void* <span class="arg">buff</span>, <span class="c">/* [OUT] Buffer to store read data */</span> UINT <span class="arg">btr</span>, <span class="c">/* [IN] Number of bytes to read */</span> UINT* <span class="arg">br</span> <span class="c">/* [OUT] Number of bytes read */</span> ); </pre> </div> <div class="para arg"> <h4>Parameters</h4> <dl class="par"> <dt>fp</dt> <dd>Pointer to the open file object.</dd> <dt>buff</dt> <dd>Pointer to the buffer to store read data.</dd> <dt>btr</dt> <dd>Number of bytes to read in range of <tt>UINT</tt> type.</dd> <dt>br</dt> <dd>Pointer to the <tt>UINT</tt> variable to return number of bytes read. The value is always valid after the function call regardless of the result code.</dd> </dl> </div> <div class="para ret"> <h4>Return Values</h4> <p> <a href="rc.html#ok">FR_OK</a>, <a href="rc.html#de">FR_DISK_ERR</a>, <a href="rc.html#ie">FR_INT_ERR</a>, <a href="rc.html#dn">FR_DENIED</a>, <a href="rc.html#io">FR_INVALID_OBJECT</a>, <a href="rc.html#tm">FR_TIMEOUT</a> </p> </div> <div class="para desc"> <h4>Description</h4> <p>The function starts to read data from the file at the position pointed by the read/write pointer. The read/write pointer advances as number of bytes read. After the function succeeded, <tt class="arg">*br</tt> should be checked to detect end of the file. In case of <tt class="arg">*br</tt> < <tt class="arg">btr</tt>, it means the read/write pointer reached end of the file during read operation.</p> </div> <div class="para comp"> <h4>QuickInfo</h4> <p>Always available.</p> </div> <div class="para ref"> <h4>See Also</h4> <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> </div> <p class="foot"><a href="../00index_e.html">Return</a></p> </body> </html>