FreeRTOS/Common/FileSystem/FatFs-0.7e/doc/en/write.html

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   8 <title>FatFs - f_write</title>
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  12
  13 <div class="para">
  14 <h2>f_write</h2>
  15 <p>The f_write writes data to a file.</p>
  16 <pre>
  17 FRESULT f_write (
  18   FIL* <em>FileObject</em>,     /* Pointer to the file object structure */
  19   const void* <em>Buffer</em>,  /* Pointer to the data to be written */
  20   UINT <em>ByteToWrite</em>,    /* Number of bytes to write */
  21   UINT* <em>ByteWritten</em>    /* Pointer to the variable to return number of bytes written */
  22 );
  23 </pre>
  24 </div>
  25
  26 <div class="para">
  27 <h4>Parameters</h4>
  28 <dl class="par">
  29 <dt>FileObject</dt>
  30 <dd>Pointer to the open file object structure.</dd>
  31 <dt>Buffer</dt>
  32 <dd>Pointer to the data to be written.</dd>
  33 <dt>ByteToWrite</dt>
  34 <dd>Specifies number of bytes to write in range of UINT.</dd>
  35 <dt>ByteWritten</dt>
  36 <dd>Pointer to the UINT variable to return the number of bytes written. The value is always valid after the function call regardless of the result.</dd>
  37 </dl>
  38 </div>
  39
  40
  41 <div class="para">
  42 <h4>Return Values</h4>
  43 <dl class="ret">
  44 <dt>FR_OK (0)</dt>
  45 <dd>The function succeeded.</dd>
  46 <dt>FR_DENIED</dt>
  47 <dd>The function denied due to the file has been opened in non-write mode.</dd>
  48 <dt>FR_DISK_ERR</dt>
  49 <dd>The function failed due to an error in the disk function.</dd>
  50 <dt>FR_INT_ERR</dt>
  51 <dd>The function failed due to a wrong FAT structure or an internal error.</dd>
  52 <dt>FR_NOT_READY</dt>
  53 <dd>The disk drive cannot work due to no medium in the drive or any other reason.</dd>
  54 <dt>FR_INVALID_OBJECT</dt>
  55 <dd>The file object is invalid.</dd>
  56 </dl>
  57 </div>
  58
  59
  60 <div class="para">
  61 <h4>Description</h4>
  62 <p>The R/W pointer in the file object is increased in number of bytes written. After the function succeeded, <tt>*ByteWritten</tt> should be checked to detect the disk full. In case of <tt>*ByteWritten &lt; ByteToWrite</tt>, it means the volume got full during the write operation.</p>
  63 </div>
  64
  65
  66 <div class="para">
  67 <h4>QuickInfo</h4>
  68 <p>Available when <tt>_FS_READONLY == 0</tt>.</p>
  69 </div>
  70
  71
  72 <div class="para">
  73 <h4>See Also</h4>
  74 <p><tt><a href="open.html">f_open</a>, <a href="read.html">f_read</a>, <a href="putc.html">fputc</a>, <a href="puts.html">fputs</a>, <a href="printf.html">fprintf</a>, <a href="close.html">f_close</a>, <a href="sfile.html">FIL</a></tt></p>
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