文件系统的读写函数open,read,write

发布于 2022-06-06 15:44:37 浏览：1091 订阅该版

```c
 /*
  * bref:写入数据
  * */
void writeData(char *data)
{
    int fd, size;
    /* 以创建和读写模式打开 /data.bin 文件，如果该文件不存在则创建该文件，存在则在文件的末尾添加*/
    fd = open("/data.bin", O_WRONLY | O_CREAT | O_APPEND);
    if (fd >= 0)
    {
        size = write(fd, data, 100);
        close(fd);
        rt_kprintf("Write data done.size:%d\n",size);
    }else {
        rt_kprintf("Write data failed\r\n");
    }
}
```

```c
/*
 * bref  :读取数据
 * param : 要读取的数据
 * ret   : 读取的大小
 * */
int readData(char *data)
{
    int fd,size = 0;
    static int i = 0;

fd = open("/data.bin", O_RDONLY);
    if(i!=0)
        lseek(fd,100*i,SEEK_SET);//每次读取后向后移动100个字节
    if(fd>=0)
    {
        size = read(fd,data,100);
        if(size !=100)
        {
            rt_kprintf("read data failed!\r\n");
            if(i!=0)
            {
                close(fd);
                //读取完毕删除文件的内容
                fd = open("/data.bin", O_WRONLY | O_TRUNC);
                close(fd);
            }
            i = 0;
        }else {
            i++;
            rt_kprintf("read data success! i:%d\r\n",i);

}
        close(fd);
        rt_kprintf("data:%d\r\n",size);
    }
    return size;
}
```