| <!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/open.html"> | |
| <link rel="stylesheet" href="../css_e.css" type="text/css" media="screen" title="ELM Default"> | |
| <title>FatFs - f_open</title> | |
| </head> | |
| <body> | |
| <div class="para"> | |
| <h2>f_open</h2> | |
| <p>The f_open function creates a <em>file object</em> to be used to access the file.</p> | |
| <pre> | |
| FRESULT f_open ( | |
| FIL* <em>FileObject</em>, <span class="c">/* Pointer to the blank file object structure */</span> | |
| const TCHAR* <em>FileName</em>, <span class="c">/* Pointer to the file neme */</span> | |
| BYTE <em>ModeFlags</em> <span class="c">/* Mode flags */</span> | |
| ); | |
| </pre> | |
| </div> | |
| <div class="para"> | |
| <h4>Parameters</h4> | |
| <dl class="par"> | |
| <dt>FileObject</dt> | |
| <dd>Pointer to the file object structure to be created.</dd> | |
| <dt>FileName</dt> | |
| <dd>Pointer to a null-terminated string that specifies the <a href="filename.html">file name</a> to create or open.</dd> | |
| <dt>ModeFlags</dt> | |
| <dd>Specifies the type of access and open method for the file. It is specified by a combination of following flags.<br> | |
| <table class="lst"> | |
| <tr><th>Value</th><th>Description</th></tr> | |
| <tr><td>FA_READ</td><td>Specifies read access to the object. Data can be read from the file.<br>Combine with FA_WRITE for read-write access.</td></tr> | |
| <tr><td>FA_WRITE</td><td>Specifies write access to the object. Data can be written to the file.<br>Combine with FA_READ for read-write access.</td></tr> | |
| <tr><td>FA_OPEN_EXISTING</td><td>Opens the file. The function fails if the file is not existing. (Default)</td></tr> | |
| <tr><td>FA_OPEN_ALWAYS</td><td>Opens the file if it is existing. If not, a new file is created.<br> | |
| To append data to the file, use f_lseek function after file open in this method.</td></tr> | |
| <tr><td>FA_CREATE_NEW</td><td>Creates a new file. The function fails with FR_EXIST if the file is existing.</td></tr> | |
| <tr><td>FA_CREATE_ALWAYS</td><td>Creates a new file. If the file is existing, it is truncated and overwritten.</td></tr> | |
| </table> | |
| </dd> | |
| </dl> | |
| </div> | |
| <div class="para"> | |
| <h4>Return Values</h4> | |
| <dl class="ret"> | |
| <dt>FR_OK (0)</dt> | |
| <dd>The function succeeded and the file object is valid.</dd> | |
| <dt>FR_NO_FILE</dt> | |
| <dd>Could not find the file.</dd> | |
| <dt>FR_NO_PATH</dt> | |
| <dd>Could not find the path.</dd> | |
| <dt>FR_INVALID_NAME</dt> | |
| <dd>The file name is invalid.</dd> | |
| <dt>FR_INVALID_DRIVE</dt> | |
| <dd>The drive number is invalid.</dd> | |
| <dt>FR_EXIST</dt> | |
| <dd>The file is already existing.</dd> | |
| <dt>FR_DENIED</dt> | |
| <dd>The required access was denied due to one of the following reasons: | |
| <ul><li>Write mode open against a read-only file.</li> | |
| <li>File cannot be created due to a directory or read-only file is existing.</li> | |
| <li>File cannot be created due to the directory table is full.</li></ul></dd> | |
| <dt>FR_NOT_READY</dt> | |
| <dd>The disk drive cannot work due to no medium in the drive or any other reason.</dd> | |
| <dt>FR_WRITE_PROTECTED</dt> | |
| <dd>Write mode open or creation under the medium is write protected.</dd> | |
| <dt>FR_DISK_ERR</dt> | |
| <dd>The function failed due to an error in the disk function.</dd> | |
| <dt>FR_INT_ERR</dt> | |
| <dd>The function failed due to a wrong FAT structure or an internal error.</dd> | |
| <dt>FR_NOT_ENABLED</dt> | |
| <dd>The logical drive has no work area.</dd> | |
| <dt>FR_NO_FILESYSTEM</dt> | |
| <dd>There is no valid FAT volume on the drive.</dd> | |
| <dt>FR_LOCKED</dt> | |
| <dd>The function was rejected due to file shareing policy (_FS_SHARE).</dd> | |
| </dl> | |
| </div> | |
| <div class="para"> | |
| <h4>Description</h4> | |
| <p>A file object is created when the function succeeded. The file object is used for subsequent read/write functions to refer to the file. When close an open file object, use <a href="close.html">f_close</a> function. If the modified file is not closed, the file data can be collapsed.</p> | |
| <p>Before using any file function, a work area (file system object) must be given to the logical drive with <a href="mount.html">f_mount</a> function. All file functions can work after this procedure.</p> | |
| </div> | |
| <div class="para"> | |
| <h4>QuickInfo</h4> | |
| <p>Always available. The mode flags, <tt>FA_WRITE, FA_CREATE_ALWAYS, FA_CREATE_NEW and FA_OPEN_ALWAYS</tt>, are not available when <tt>_FS_READONLY == 1</tt>.</p> | |
| </div> | |
| <div class="para"> | |
| <h4>Example (File Copy)</h4> | |
| <pre> | |
| void main (void) | |
| { | |
| FATFS fs[2]; <span class="c">/* Work area (file system object) for logical drives */</span> | |
| FIL fsrc, fdst; <span class="c">/* file objects */</span> | |
| BYTE buffer[4096]; <span class="c">/* file copy buffer */</span> | |
| FRESULT res; <span class="c">/* FatFs function common result code */</span> | |
| UINT br, bw; <span class="c">/* File read/write count */</span> | |
| <span class="c">/* Register work area for each volume (Always succeeds regardless of disk status) */</span> | |
| f_mount(0, &fs[0]); | |
| f_mount(1, &fs[1]); | |
| <span class="c">/* Open source file on the drive 1 */</span> | |
| res = f_open(&fsrc, "1:srcfile.dat", FA_OPEN_EXISTING | FA_READ); | |
| if (res) die(res); | |
| <span class="c">/* Create destination file on the drive 0 */</span> | |
| res = f_open(&fdst, "0:dstfile.dat", FA_CREATE_ALWAYS | FA_WRITE); | |
| if (res) die(res); | |
| <span class="c">/* Copy source to destination */</span> | |
| for (;;) { | |
| res = f_read(&fsrc, buffer, sizeof(buffer), &br); <span class="c">/* Read a chunk of src file */</span> | |
| if (res || br == 0) break; <span class="c">/* error or eof */</span> | |
| res = f_write(&fdst, buffer, br, &bw); <span class="c">/* Write it to the dst file */</span> | |
| if (res || bw < br) break; <span class="c">/* error or disk full */</span> | |
| } | |
| <span class="c">/* Close open files */</span> | |
| f_close(&fsrc); | |
| f_close(&fdst); | |
| <span class="c">/* Unregister work area prior to discard it */</span> | |
| f_mount(0, NULL); | |
| f_mount(1, NULL); | |
| } | |
| </pre> | |
| </div> | |
| <div class="para"> | |
| <h4>See Also</h4> | |
| <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> | |
| </div> | |
| <p class="foot"><a href="../00index_e.html">Return</a></p> | |
| </body> | |
| </html> |