Does inpout32.dll/inpoutx64.dll handle I/O to/from all parallel ports?

Question

Days of research and programming have led me to try all variants of inpout32.dll and inpoutx64.dll: binaries, source code, 32-bit, 64-bit, address wrappers. None work: no change is seen to the output bits of the port.

However, I know it is possible, because using another commercially available program that does parallel port output, I can detect a trigger (state change) on all eight output bits (D0-D7) by passing a value between 0 and 255, exactly what I want to do in my own application.

I have followed all the advice from at least these pages:

• Write to parallel port in Windows 7
• C# LPT inpout32.dll
• C# - Read Parallel Port State (Simple Push Switch)
• Write to a parallel port on windows 7
• Parallel port with C#
• http://www.lvr.com/parport.htm

I am using Windows 7, 64-bit; and my SIIG Cyberpro port is mapped as LPT3 at address 0xCCD8, with four status bits at address 0xCCD4. I have another ECP printer port mapped as LPT1 at 0x0378, but that does not work either.

I know better than to try direct _inp(), _outp() calls on Win7.

Can anyone help?

If I need to download and modify the driver code, I can do that if I have to, but I think it should not be that difficult.

My final version of code uses 32-bit compilation, interfacing to inpout32.dll:

using System;
using System.Runtime.InteropServices;

namespace ParallelPort
{
    public class PortAccess
    {
        //inpout.dll

        [DllImport("inpout32.dll")]
        private static extern void Out32(ushort PortAddress, short Data);

        [DllImport("inpout32.dll")]
        private static extern short Inp32(ushort PortAddress);

        private ushort _PortAddress = 0;

        public ushort PortAddress { get { return _PortAddress; } }

        public PortAccess(ushort portAddress)
        {
            _PortAddress = portAddress;

            short result = 0;
            try
            {
                result = Inp32(portAddress);
            }
            catch (DllNotFoundException e)
            {
                throw new ArgumentException("Unable to find InpOut32.dll");
            }
            catch (BadImageFormatException)
            {
                result = 0;
            }

            if (0 == result)
                throw new ArgumentException("Unable to open parallel port driver");
        }

        //Public Methods
        public void Write(ushort Data)
        {
            Out32(_PortAddress, (short)Data);
        }

        public byte Read()
        {
            return (byte)Inp32(_PortAddress);
        }
    }
}

Answer 1

FYI:

When I added

 [DllImport("inpout32.dll")]
 private static extern void DlPortWritePortUshort(ushort PortAddress, ushort Data);

and called that function rather than Out32(ushort addr, ushort value) the code worked.

I don't know why the exact interface matters, but it does; and perhaps that is indeed because of sign extension on the 16-bit port address, as suggested [somewhere TBD].