DeviceIoControl 返回错误码1，为什么？

[rokia]

if(!DeviceIoControl(
hRootOfVolume,
IOCTL_CHANGER_GET_PRODUCT_DATA,
NULL,
0,
&product_data,
sizeof(product_data),
&returnsize,
NULL))

执行过后，用getlasterror()得到 1,（含义是功能错误）

为什么？ 另外哪位大虾知道changer是什么意思？

这个问题搞了好长时间了。 我就是想得到一个volume对应的硬件是个什么东西。主要是针对移动存储，例如当用户插入一个数码相机的时候，我能知道新出来的盘符对应的是数码相机。

大恩不言谢，只有倾囊相赠了！！

[oldworm]

DeviceIoControl第二个参数好像没有
IOCTL_CHANGER_GET_PRODUCT_DATA　这么个值
你这里搞错了，所以出现功能错误（根本不支持这个功能嘛）


你可以用
UINT GetDriveType(
LPCTSTR lpRootPathName // root directory
);
得到对应盘是什么类型，返回类型有下面这些：

DRIVE_UNKNOWN The drive type cannot be determined.
DRIVE_NO_ROOT_DIR The root path is invalid. For example, no volume is mounted at the path.
DRIVE_REMOVABLE The disk can be removed from the drive.
DRIVE_FIXED The disk cannot be removed from the drive.
DRIVE_REMOTE The drive is a remote (network) drive.
DRIVE_CDROM The drive is a CD-ROM drive.
DRIVE_RAMDISK The drive is a RAM disk.

你的数码相机大概是属于DRIVE_REMOVABLE 类型。

[rokia]

你的SDK太舊了，升級一下就有了。

我的程序不但要知道它是 Removable,還想知道這是數碼相機。

[wuxuan]

/* The code of interest is in the subroutine GetDriveGeometry. The
code in main shows how to interpret the results of the IOCTL call. */

#include <windows.h>
#include <winioctl.h>

BOOL
GetDriveGeometry(DISK_GEOMETRY *pdg)
{
HANDLE hDevice; // handle to the drive to be examined
BOOL bResult; // results flag
DWORD junk; // discard results

hDevice = CreateFile("\\\\.\\PhysicalDrive0", // drive to open
0, // don't need any access to the drive
FILE_SHARE_READ | FILE_SHARE_WRITE, // share mode
NULL, // default security attributes
OPEN_EXISTING, // disposition
0, // file attributes
NULL); // don't copy any file's attributes

if (hDevice == INVALID_HANDLE_VALUE) // we can't open the drive
{
return (FALSE);
}

bResult = DeviceIoControl(hDevice, // device we are querying
IOCTL_DISK_GET_DRIVE_GEOMETRY, // operation to perform
NULL, 0, // no input buffer, so pass zero
pdg, sizeof(*pdg), // output buffer
&junk, // discard count of bytes returned
(LPOVERLAPPED) NULL); // synchronous I/O

CloseHandle(hDevice); // we're done with the handle

return (bResult);
}

int
main(int argc, char *argv[])
{
DISK_GEOMETRY pdg; // disk drive geometry structure
BOOL bResult; // generic results flag
ULONGLONG DiskSize; // size of the drive, in bytes

bResult = GetDriveGeometry (&pdg);

if (bResult)
{
printf("Cylinders = %I64d\n", pdg.Cylinders);
printf("Tracks per cylinder = %ld\n", (ULONG) pdg.TracksPerCylinder);
printf("Sectors per track = %ld\n", (ULONG) pdg.SectorsPerTrack);
printf("Bytes per sector = %ld\n", (ULONG) pdg.BytesPerSector);

DiskSize = pdg.Cylinders.QuadPart * (ULONG)pdg.TracksPerCylinder *
(ULONG)pdg.SectorsPerTrack * (ULONG)pdg.BytesPerSector;
printf("Disk size = %I64d (Bytes) = %I64d (Mb)\n", DiskSize,
DiskSize / (1024 * 1024));
} else {
printf ("Attempt to get drive geometry failed. Error %ld.\n",
GetLastError ());
}

return ((int)bResult);
}

[rokia]

再來頂一下。

看來沒希望了。：(

[wuxuan]

Windows 95/98/Me: Unsupported.
你使用的是什么操作系统？

[rokia]

我用的XP。