Find current connected USB storage path in C++

Question

My Env:

Qt 5.3.1
Windows 10

I need to find the path of mounted USB storage devices. Through the path, I can copy the files via Qt. I know t

Answer 1

First you need to get removable drives:

void EnumUsbDrives() {
    DWORD drv = ::GetLogicalDrives();
    if (drv == 0) return;

    DWORD mask = 1;
    TCHAR szDrive[] = _TEXT("?:\\");

    for (uint_t i = 0; i < ('Z' - 'A' + 1); i++, mask <<= 1) {
        if (drv & mask) {
            szDrive[0] = (TCHAR)(_T('A') + i);
            if (::GetDriveType(szDrive) == DRIVE_REMOVABLE) {
                bool bUSB = IsDriveUSB(szDrive);
                if (bUSB) {
                    // Time do to something useful
                }
            }
        }
    }
}

Function IsDriveUSB is a bit more complicated. I have teared it from an in-house library; the function uses custom helper classes xregistry and xstring_nocase. Their purpose is pretty obvious, I believe you will have no trouble replacing it with other similar classes or API calls.

bool IsDriveUSB (LPCTSTR szDrive) throw() {
    TCHAR szLogicalDrive[] = _TEXT("\\\\.\\x:");
    szLogicalDrive[4] = szDrive[0];
    HANDLE hDrive = ::CreateFile(szLogicalDrive, FILE_READ_ATTRIBUTES, FILE_SHARE_READ | FILE_SHARE_WRITE, NULL, OPEN_EXISTING, 0, NULL);
    if (hDrive == INVALID_HANDLE_VALUE) return false;       // Can't open drive so we have to assume the drive is fixed

    VOLUME_DISK_EXTENTS vde;
    DWORD dwBytesReturned = 0;
    BOOL br = ::DeviceIoControl(hDrive, IOCTL_VOLUME_GET_VOLUME_DISK_EXTENTS, NULL, 0, &vde, sizeof(vde), &dwBytesReturned, NULL);
    ::CloseHandle(hDrive);
    if (!br) return false;      // Can't get extents info so we have to assume the drive is fixed

    if (vde.NumberOfDiskExtents != 1) return false;
    ULONG uPhysDrive = vde.Extents[0].DiskNumber;
    TCHAR szPhysDrive[16];
    _stprintf(szPhysDrive, _TEXT("%u"), uPhysDrive);

    try {
        xregistry rk(HKEY_LOCAL_MACHINE, OS.Is64bit());
        rk.open(_TEXT("SYSTEM\\CurrentControlSet\\services\\Disk\\Enum"), KEY_QUERY_VALUE);
        if (!rk.value_exists(szPhysDrive)) return false;
        xstring_nocase strInterface = rk.get_string(szPhysDrive).substring(0, 7);
        return strInterface == _TEXT("USBSTOR");
    }
    catch (...) {
        return false;
    }
}