diff options
Diffstat (limited to 'examples/file')
| -rw-r--r-- | examples/file/readwrite.c | 44 |
1 files changed, 23 insertions, 21 deletions
diff --git a/examples/file/readwrite.c b/examples/file/readwrite.c index 8dc29837ef..17d173c353 100644 --- a/examples/file/readwrite.c +++ b/examples/file/readwrite.c @@ -1,30 +1,24 @@ /*
- * File : readwrite.c
- * This file is part of RT-TestCase in RT-Thread RTOS
- * COPYRIGHT (C) 2010, RT-Thread Development Team
+ * 代码清单：文件读写例子
*
- * The license and distribution terms for this file may be
- * found in the file LICENSE in this distribution or at
- * http://www.rt-thread.org/license/LICENSE
- *
- * Change Logs:
- * Date Author Notes
- * 2010-02-10 Bernard first version
+ * 这个例子演示了如何读写一个文件，特别是写的时候应该如何操作。
*/
+
#include <rtthread.h>
-#include <dfs_posix.h>
+#include <dfs_posix.h> /* 当需要使用文件操作时，需要包含这个头文件 */
#define TEST_FN "/test.dat"
+/* 测试用的数据和缓冲 */
static char test_data[120], buffer[120];
-/* �ļ���д���� */
+/* 文件读写测试 */
void readwrite(const char* filename)
{
int fd;
int index, length;
- /* ֻд & ���� �� */
+ /* 只写 & 创建 打开 */
fd = open(TEST_FN, O_WRONLY | O_CREAT | O_TRUNC, 0);
if (fd < 0)
{
@@ -32,13 +26,13 @@ void readwrite(const char* filename) return;
}
- /* ������� */
+ /* 准备写入数据 */
for (index = 0; index < sizeof(test_data); index ++)
{
test_data[index] = index + 27;
}
- /* ����� */
+ /* 写入数据 */
length = write(fd, test_data, sizeof(test_data));
if (length != sizeof(test_data))
{
@@ -47,10 +41,10 @@ void readwrite(const char* filename) return;
}
- /* �ر��ļ� */
+ /* 关闭文件 */
close(fd);
- /* ֻд����ĩβ���Ӵ� */
+ /* 只写并在末尾添加打开 */
fd = open(TEST_FN, O_WRONLY | O_CREAT | O_APPEND, 0);
if (fd < 0)
{
@@ -65,10 +59,10 @@ void readwrite(const char* filename) close(fd);
return;
}
- /* �ر��ļ� */
+ /* 关闭文件 */
close(fd);
- /* ֻ����������У�� */
+ /* 只读打开进行数据校验 */
fd = open(TEST_FN, O_RDONLY, 0);
if (fd < 0)
{
@@ -76,6 +70,7 @@ void readwrite(const char* filename) return;
}
+ /* 读取数据(应该为第一次写入的数据) */
length = read(fd, buffer, sizeof(buffer));
if (length != sizeof(buffer))
{
@@ -83,6 +78,8 @@ void readwrite(const char* filename) close(fd);
return;
}
+
+ /* 检查数据是否正确 */
for (index = 0; index < sizeof(test_data); index ++)
{
if (test_data[index] != buffer[index])
@@ -93,6 +90,7 @@ void readwrite(const char* filename) }
}
+ /* 读取数据(应该为第二次写入的数据) */
length = read(fd, buffer, sizeof(buffer));
if (length != sizeof(buffer))
{
@@ -100,6 +98,8 @@ void readwrite(const char* filename) close(fd);
return;
}
+
+ /* 检查数据是否正确 */
for (index = 0; index < sizeof(test_data); index ++)
{
if (test_data[index] != buffer[index])
@@ -109,13 +109,15 @@ void readwrite(const char* filename) return;
}
}
- /* ���������ϣ��ر��ļ� */
+
+ /* 检查数据完毕，关闭文件 */
close(fd);
- /* ��ӡ��� */
+ /* 打印结果 */
rt_kprintf("read/write done.\n");
}
#ifdef RT_USING_FINSH
#include <finsh.h>
+/* 输出函数到finsh shell命令行中 */
FINSH_FUNCTION_EXPORT(readwrite, perform file read and write test);
#endif
|