Why does DeviceIoControl throw error 21 (Device Not Ready) from C# when the equivalent in C works fine?
- by Ragesh
I'm trying to send an IOCTL_SERVICE_REFRESH command to the GPS Intermediate Driver service using C# like this:
handle = CreateFile("GPD0:",
GENERIC_READ,
FILE_SHARE_READ | FILE_SHARE_WRITE,
IntPtr.Zero,
OPEN_EXISTING,
FILE_ATTRIBUTE_NORMAL,
IntPtr.Zero);
if (handle.ToInt32() == INVALID_HANDLE_VALUE)
{
rc = Marshal.GetLastWin32Error();
return rc;
}
int numBytesReturned = 0;
rc = DeviceIoControl(
handle,
IOCTL_SERVICE_REFRESH,
null,
0,
null,
0,
ref numBytesReturned,
IntPtr.Zero);
int error = Marshal.GetLastWin32Error();
GetLastWin32Error always gives me error 21 (device not ready). However, the equivalent call when made from C++ works fine:
HANDLE hGPS = CreateFile(L"GPD0:", GENERIC_READ, FILE_SHARE_READ | FILE_SHARE_WRITE, 0, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, 0);
if (hGPS != INVALID_HANDLE_VALUE) {
BOOL ret = DeviceIoControl(hGPS,IOCTL_SERVICE_REFRESH,0,0,0,0,0,0);
DWORD err = GetLastError();
}
I suspected a problem with the PInvoke signatures, but I can't seem to find anything wrong here:
[DllImport("coredll.dll", EntryPoint = "DeviceIoControl", SetLastError = true)]
public static extern int DeviceIoControl(
IntPtr hDevice,
uint dwIoControlCode,
byte[] lpInBuffer,
int nInBufferSize,
byte[] lpOutBuffer,
int nOutBufferSize,
ref int lpBytesReturned,
IntPtr lpOverlapped);
[DllImport("coredll.dll", SetLastError = true)]
public static extern IntPtr CreateFile(
String lpFileName,
uint dwDesiredAccess,
uint dwShareMode,
IntPtr attr,
uint dwCreationDisposition,
uint dwFlagsAndAttributes,
IntPtr hTemplateFile);
What am I missing here?
