Hi Im trying tu use deviceiocontrol to retrieve serial port informationin a
C#project.
The problem is that i cant make it work. it gives me always the same error.
The function returns a win32 error telling me that the parameter is not valid
The problem is that i dont know which parameter is the function referring to.
I have tried everything to make it work but i cant
I create the handle to the serial port correctly in the overlapped mode. I
call some functions to change different parameters of the serial port and
everything goes fine, none of the imported functions gives me any error.
But when i finally call DeviceiOcONTROL:

IntPtr control = Marshal.AllocHGlobal(3);
           IntPtr stats = Marshal.AllocHGlobal(24);
           IntPtr BaudRate = Marshal.AllocHGlobal(4);
           if (hFile != IntPtr.Zero)
           {
               if (false != DeviceIoControl(hFile,
IOCTL_SERIAL_GET_LINE_CONTROL, IntPtr.Zero, 0, control, 3, out returned,
IntPtr.Zero))
               {
                   SERIAL_LINE_CONTROL c =
(SERIAL_LINE_CONTROL)Marshal.PtrToStructure(control,
typeof(SERIAL_LINE_CONTROL));
                   arg.DataBits = c.WordLenght;
                   arg.bitsStop = c.StopBits;
                   arg.paridad = c.Parity;
               }
               else
               {
                   MessageBox.Show(new
System.ComponentModel.Win32Exception(Marshal.GetLastWin32Error()).Message);
                   arg.DataBits = -1;
                   arg.bitsStop = -1;
                   arg.paridad = -1;
               }

i always enter the else clause and it gives me the "inbcorrect parameter"
error.
¿Somebody knows which parameter could be referring to?
Many thanks