Even if this post is a bit old, I found another way to get a fully populated PartitionEntry without creating a tricky struct:
According to this post: How to call DeviceIoControl to retrieve the amount of memory it needs?
DRIVE_LAYOUT_INFORMATION_EX dli;
DWORD bytesReturned = 0;
if (!DeviceIoControl(hDevice, IOCTL_DISK_GET_DRIVE_LAYOUT_EX, NULL, 0, (void*)&dli, sizeof(dli), &bytesReturned, NULL))
{
// Check last error if not ERROR_INSUFFICIENT_BUFFER then return
int nError = GetLastError();
if (nError != ERROR_INSUFFICIENT_BUFFER)
{
// std::cout << "DeviceIoControl() Failed: " << nError << std::endl;
CloseHandle(hDevice);
return false;
}
// Allocate enough buffer space based of the value of Partition Count:
size_t size = offsetof(DRIVE_LAYOUT_INFORMATION_EX, PartitionEntry[dli.PartitionCount]);
std::vector<BYTE> buffer(size);
if (!DeviceIoControl(hDevice, IOCTL_DISK_GET_DRIVE_LAYOUT_EX, NULL, 0, (void*)buffer.data(), size, &bytesReturned, NULL))
{
nError = GetLastError();
// std::cout << "DeviceIoControl() Failed: " << nError << std::endl;
CloseHandle(hDevice);
return false;
}
const DRIVE_LAYOUT_INFORMATION_EX& result = *reinterpret_cast<const DRIVE_LAYOUT_INFORMATION_EX*>(buffer.data());
// Here all parition entry are populated ...
// TO DO... Do your stuff with result
}
else
{
// Call succeeded; dli is populated with a signle partition entry
// TO DO... Do your stuff with dli
}