WriteFile写磁盘扇区是87错误的原因

今天在写个工具,功能是将一些数据写到磁盘的绝对扇区上.

但是发现ReadFile没问题,可是WriteFile总是报87错误(参数不正确).

Google上查了一会,发现碰到问题的人不少,可惜没有正确答案....

没辙,还是啃MSDN,终于还是自己解决了~呵呵

赶紧记下来,免得忘了...

 

其实主要是写入的数据大小,必须是BytesOfSector大小的倍数,一般是512字节,ReadFile却无所谓...

另外,MSDN上还说,WriteFile前最好先用FSCTL_LOCK_VOLUME或者FSCTL_DISMOUNT_VOLUME将磁盘锁定或卸载,不过我试下来好像没什么影响...

代码摘录如下:

 

 1 UINT CDevInfo::Write(LPVOID pData, UINT nSize)
 2 {
 3     if (!pData && nSize <= 0)
 4         return 0;
 5 
 6     TCHAR szDevName[30];
 7     _stprintf(szDevName, _T("\\\\.\\PHYSICALDRIVE%d"), m_nDevNum); // DeviceNumber
 8 
 9     HANDLE hDev = ::CreateFile(szDevName, GENERIC_WRITE, FILE_SHARE_READ | FILE_SHARE_WRITE, NULL, OPEN_EXISTING, NULL, NULL);
10     if (hDev == INVALID_HANDLE_VALUE)
11         return 0;
12 
13     DWORD dwCount;
14     if (!::DeviceIoControl(hDev, FSCTL_LOCK_VOLUME, NULL, 0, NULL, 0, &dwCount, NULL))
15         return 0;
16 
17     DWORD dwWritten(0);
18     ::SetFilePointer(hDev, SECTOR_NUM * GetSectorSize(), NULL, FILE_BEGIN);
19     if (!::WriteFile(hDev, pData, nSize, &dwWritten, NULL))
20         dwWritten = 0;
21     
22     ::DeviceIoControl(hDev, FSCTL_UNLOCK_VOLUME, NULL, 0, NULL, 0, &dwCount, NULL);
23     ::CloseHandle(hDev);
24     return dwWritten;
25 }