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Import fatfs R0.13b
[z180-stamp.git] / fatfs / documents / doc / open.html
CommitLineData
53668523
L		 1<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">\r
2<html lang="en">\r
3<head>\r
289f6a14 4<meta http-equiv="Content-Type" content="text/html; charset=utf-8">\r
53668523
L		 5<meta http-equiv="Content-Style-Type" content="text/css">\r
6<link rel="up" title="FatFs" href="../00index_e.html">\r
7<link rel="alternate" hreflang="ja" title="Japanese" href="../ja/open.html">\r
8<link rel="stylesheet" href="../css_e.css" type="text/css" media="screen" title="ELM Default">\r
9<title>FatFs - f_open</title>\r
10</head>\r
11\r
12<body>\r
13\r
14<div class="para func">\r
15<h2>f_open</h2>\r
289f6a14 16<p>The f_open function opens a file.</p>\r
53668523
L		 17<pre>\r
18FRESULT f_open (\r
19 FIL* <span class="arg">fp</span>, <span class="c">/* [OUT] Pointer to the file object structure */</span>\r
20 const TCHAR* <span class="arg">path</span>, <span class="c">/* [IN] File name */</span>\r
21 BYTE <span class="arg">mode</span> <span class="c">/* [IN] Mode flags */</span>\r
22);\r
23</pre>\r
24</div>\r
25\r
26<div class="para arg">\r
27<h4>Parameters</h4>\r
28<dl class="par">\r
29<dt>fp</dt>\r
70702af1 30<dd>Pointer to the blank file object structure.</dd>\r
53668523 31<dt>path</dt>\r
70702af1 32<dd>Pointer to the null-terminated string that specifies the <a href="filename.html">file name</a> to open or create.</dd>\r
53668523
L		 33<dt>mode</dt>\r
34<dd>Mode flags that specifies the type of access and open method for the file. It is specified by a combination of following flags.<br>\r
35<table class="lst">\r
289f6a14 36<tr><th>Flags</th><th>Meaning</th></tr>\r
70702af1 37<tr><td>FA_READ</td><td>Specifies read access to the object. Data can be read from the file.</tr>\r
53668523
L		 38<tr><td>FA_WRITE</td><td>Specifies write access to the object. Data can be written to the file. Combine with <tt>FA_READ</tt> for read-write access.</td></tr>\r
39<tr><td>FA_OPEN_EXISTING</td><td>Opens the file. The function fails if the file is not existing. (Default)</td></tr>\r
53668523
L		 40<tr><td>FA_CREATE_NEW</td><td>Creates a new file. The function fails with <tt>FR_EXIST</tt> if the file is existing.</td></tr>\r
41<tr><td>FA_CREATE_ALWAYS</td><td>Creates a new file. If the file is existing, it will be truncated and overwritten.</td></tr>\r
70702af1 42<tr><td>FA_OPEN_ALWAYS</td><td>Opens the file if it is existing. If not, a new file will be created.</td></tr>\r
289f6a14
L		 43<tr><td>FA_OPEN_APPEND</td><td>Same as <tt>FA_OPEN_ALWAYS</tt> except the read/write pointer is set end of the file.</td></tr>\r
44</table>\r
45Mode flags of POSIX fopen() corresponds to FatFs mode flags as follows:<br>\r
46<table class="lst2">\r
47<tr><th>POSIX</th><th>FatFs</th></tr>\r
48<tr><td>"r"</td><td>FA_READ</td></tr>\r
49<tr><td>"r+"</td><td>FA_READ | FA_WRITE</td></tr>\r
50<tr><td>"w"</td><td>FA_CREATE_ALWAYS | FA_WRITE</td></tr>\r
51<tr><td>"w+"</td><td>FA_CREATE_ALWAYS | FA_WRITE | FA_READ</td></tr>\r
52<tr><td>"a"</td><td>FA_OPEN_APPEND | FA_WRITE</td></tr>\r
53<tr><td>"a+"</td><td>FA_OPEN_APPEND | FA_WRITE | FA_READ</td></tr>\r
54<tr><td>"wx"</td><td>FA_CREATE_NEW | FA_WRITE</td></tr>\r
55<tr><td>"w+x"</td><td>FA_CREATE_NEW | FA_WRITE | FA_READ</td></tr>\r
53668523
L		 56</table>\r
57</dd>\r
58</dl>\r
59</div>\r
60\r
61\r
62<div class="para ret">\r
63<h4>Return Values</h4>\r
64<p>\r
65<a href="rc.html#ok">FR_OK</a>,\r
66<a href="rc.html#de">FR_DISK_ERR</a>,\r
67<a href="rc.html#ie">FR_INT_ERR</a>,\r
68<a href="rc.html#nr">FR_NOT_READY</a>,\r
289f6a14 69<a href="rc.html#nf">FR_NO_FILE</a>,\r
53668523
L		 70<a href="rc.html#np">FR_NO_PATH</a>,\r
71<a href="rc.html#in">FR_INVALID_NAME</a>,\r
289f6a14 72<a href="rc.html#dn">FR_DENIED</a>,\r
53668523
L		 73<a href="rc.html#ex">FR_EXIST</a>,\r
74<a href="rc.html#io">FR_INVALID_OBJECT</a>,\r
75<a href="rc.html#wp">FR_WRITE_PROTECTED</a>,\r
76<a href="rc.html#id">FR_INVALID_DRIVE</a>,\r
77<a href="rc.html#ne">FR_NOT_ENABLED</a>,\r
78<a href="rc.html#ns">FR_NO_FILESYSTEM</a>,\r
79<a href="rc.html#tm">FR_TIMEOUT</a>,\r
80<a href="rc.html#lo">FR_LOCKED</a>,\r
81<a href="rc.html#nc">FR_NOT_ENOUGH_CORE</a>,\r
82<a href="rc.html#tf">FR_TOO_MANY_OPEN_FILES</a>\r
83</p>\r
84</div>\r
85\r
86\r
87<div class="para desc">\r
88<h4>Description</h4>\r
289f6a14 89<p>The <tt>f_open</tt> function opens a file and creates a <em>file object</em>. The file object is used for subsequent read/write operations to the file to identify the file. Open file should be closed with <a href="close.html"><tt>f_close</tt></a> function after the session of the file access. If any change to the file is made and not closed prior to power down, media removal or re-mount, or the file can be collapsed.</p>\r
70702af1 90<p>If duplicated file open is needed, read <a href="appnote.html#dup">here</a> carefully. However duplicated open of a file with any write mode flag is always prohibited.</p>\r
53668523
L		 91</div>\r
92\r
93\r
94<div class="para comp">\r
95<h4>QuickInfo</h4>\r
289f6a14 96<p>Always available. Only <tt>FA_READ</tt> and <tt>FA_OPEN_EXISTING</tt> are available for the mode flags when <tt><a href="config.html#fs_readonly">FF_FS_READONLY</a> == 1</tt>.</p>\r
53668523
L		 97</div>\r
98\r
99\r
100<div class="para use">\r
101<h4>Example</h4>\r
102<pre>\r
103<span class="c">/* Read a text file and display it */</span>\r
104\r
289f6a14 105FATFS FatFs; <span class="c">/* Work area (filesystem object) for logical drive */</span>\r
53668523
L		 106\r
107int main (void)\r
108{\r
289f6a14
L		 109 FIL fil; <span class="c">/* File object */</span>\r
110 char line[100]; <span class="c">/* Line buffer */</span>\r
111 FRESULT fr; <span class="c">/* FatFs return code */</span>\r
53668523
L		 112\r
113\r
114 <span class="c">/* Register work area to the default drive */</span>\r
115 f_mount(&amp;FatFs, "", 0);\r
116\r
117 <span class="c">/* Open a text file */</span>\r
289f6a14 118 fr = <em>f_open</em>(&amp;fil, "message.txt", FA_READ);\r
53668523
L		 119 if (fr) return (int)fr;\r
120\r
121 <span class="c">/* Read all lines and display it */</span>\r
289f6a14 122 while (f_gets(line, sizeof line, &amp;fil)) {\r
53668523 123 printf(line);\r
289f6a14 124 }\r
53668523
L		 125\r
126 <span class="c">/* Close the file */</span>\r
127 f_close(&amp;fil);\r
128\r
129 return 0;\r
130}\r
131</pre>\r
132<pre>\r
133<span class="c">/* Copy a file "file.bin" on the drive 1 to drive 0 */</span>\r
134\r
135int main (void)\r
136{\r
289f6a14 137 FATFS fs[2]; <span class="c">/* Work area (filesystem object) for logical drives */</span>\r
53668523
L		 138 FIL fsrc, fdst; <span class="c">/* File objects */</span>\r
139 BYTE buffer[4096]; <span class="c">/* File copy buffer */</span>\r
140 FRESULT fr; <span class="c">/* FatFs function common result code */</span>\r
141 UINT br, bw; <span class="c">/* File read/write count */</span>\r
142\r
143\r
144 <span class="c">/* Register work area for each logical drive */</span>\r
145 f_mount(&amp;fs[0], "0:", 0);\r
146 f_mount(&amp;fs[1], "1:", 0);\r
147\r
148 <span class="c">/* Open source file on the drive 1 */</span>\r
289f6a14 149 fr = <em>f_open</em>(&amp;fsrc, "1:file.bin", FA_READ);\r
53668523
L		 150 if (fr) return (int)fr;\r
151\r
152 <span class="c">/* Create destination file on the drive 0 */</span>\r
289f6a14 153 fr = <em>f_open</em>(&amp;fdst, "0:file.bin", FA_WRITE | FA_CREATE_ALWAYS);\r
53668523
L		 154 if (fr) return (int)fr;\r
155\r
156 <span class="c">/* Copy source to destination */</span>\r
157 for (;;) {\r
158 fr = f_read(&amp;fsrc, buffer, sizeof buffer, &amp;br); <span class="c">/* Read a chunk of source file */</span>\r
159 if (fr || br == 0) break; <span class="c">/* error or eof */</span>\r
160 fr = f_write(&amp;fdst, buffer, br, &amp;bw); <span class="c">/* Write it to the destination file */</span>\r
161 if (fr || bw &lt; br) break; <span class="c">/* error or disk full */</span>\r
162 }\r
163\r
164 <span class="c">/* Close open files */</span>\r
165 f_close(&amp;fsrc);\r
166 f_close(&amp;fdst);\r
167\r
168 <span class="c">/* Unregister work area prior to discard it */</span>\r
169 f_mount(NULL, "0:", 0);\r
170 f_mount(NULL, "1:", 0);\r
171\r
172 return (int)fr;\r
173}\r
174</pre>\r
175</div>\r
176\r
177\r
178<div class="para ref">\r
179<h4>See Also</h4>\r
180<p><tt><a href="read.html">f_read</a>, <a href="write.html">f_write</a>, <a href="close.html">f_close</a>, <a href="sfile.html">FIL</a>, <a href="sfatfs.html">FATFS</a></tt></p>\r
181</div>\r
182\r
183<p class="foot"><a href="../00index_e.html">Return</a></p>\r
184</body>\r
185</html>\r
Z180 Stamp Monitor