diff options
Diffstat (limited to '3rdparty/petitfs-0.03/doc/pf/write.html')
| -rw-r--r-- | 3rdparty/petitfs-0.03/doc/pf/write.html | 86 |
1 files changed, 86 insertions, 0 deletions
diff --git a/3rdparty/petitfs-0.03/doc/pf/write.html b/3rdparty/petitfs-0.03/doc/pf/write.html new file mode 100644 index 00000000..573a298b --- /dev/null +++ b/3rdparty/petitfs-0.03/doc/pf/write.html @@ -0,0 +1,86 @@ +<!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="Petit FatFs" href="../00index_p.html"> +<link rel="stylesheet" href="../css_e.css" type="text/css" media="screen" title="ELM Default"> +<link rel="stylesheet" href="../css_p.css" type="text/css" media="screen" title="ELM Default"> +<title>Petit FatFs - pf_write</title> +</head> + +<body> + +<div class="para"> +<h2>pf_write</h2> +<p>The pf_write function writes data to the file.</p> +<pre> +FRESULT pf_write ( + const void* <span class="arg">buff</span>, <span class="c">/* [IN] Pointer to the data to be written */</span> + UINT <span class="arg">btw</span>, <span class="c">/* [IN] Number of bytes to write */</span> + UINT* <span class="arg">bw</span> <span class="c">/* [OUT] Pointer to the variable to return number of bytes written */</span> +); +</pre> +</div> + +<div class="para"> +<h4>Parameters</h4> +<dl class="par"> +<dt>buff</dt> +<dd>Pointer to the data to be wtitten. A NULL specifies to finalize the current write operation.</dd> +<dt>btw</dt> +<dd>Number of bytes to write.</dd> +<dt>bw</dt> +<dd>Pointer to the variable to return number of bytes read.</dd> +</dl> +</div> + + +<div class="para"> +<h4>Return Values</h4> +<dl class="ret"> +<dt>FR_OK (0)</dt> +<dd>The function succeeded.</dd> +<dt>FR_DISK_ERR</dt> +<dd>The function failed due to a hard error in the disk function, write protected, a wrong FAT structure or an internal error.</dd> +<dt>FR_NOT_OPENED</dt> +<dd>The file has not been opened.</dd> +<dt>FR_NOT_ENABLED</dt> +<dd>The volume has not been mounted.</dd> +</dl> +</div> + + +<div class="para"> +<h4>Description</h4> +<p>The write function has some restrictions listed below:</p> +<ul> +<li>Cannot create file. Only existing file can be written.</li> +<li>Cannot expand file size.</li> +<li>Cannot update time stamp of the file.</li> +<li>Write operation can start/stop on the sector boundary.</li> +<li>Read-only attribute of the file cannot block write operation.</li> +</ul> +<p>File write operation must be done in following sequence.</p> +<ol> +<li><tt>pf_lseek(ofs);</tt> read/write pointer must be moved to sector bundary prior to initiate write operation or it will be rounded-down to the sector boundary.</li> +<li><tt>pf_write(buff, btw, &bw);</tt> Initiate write operation. Write first data to the file.</li> +<li><tt>pf_write(buff, btw, &bw);</tt> Write next data. Any other file function cannot be used while a write operation is in progress.</li> +<li><tt>pf_write(0, 0, &bw);</tt> Finalize the write operation. If read/write pointer is not on the sector boundary, left bytes in the sector will be filled with zero.</li> +</ol> +<p>The read/write pointer in the file system object advances in number of bytes written. After the function succeeded, <tt>*bw</tt> should be checked to detect end of file. In case of <tt>*bw < btw</tt>, it means the read/write pointer reached end of file during the write operation. Once a write operation is initiated, it must be finalized or the written data can be lost.</p> +</div> + +<div class="para"> +<h4>QuickInfo</h4> +<p>Available when <tt>_USE_WRITE == 1</tt>.</p> +</div> + +<div class="para"> +<h4>References</h4> +<p><tt><a href="open.html">pf_open</a>, <a href="sfatfs.html">FATFS</a></tt></p> +</div> + +<p class="foot"><a href="../00index_p.html">Return</a></p> +</body> +</html> |