I'm trying to rewrite "c" code to "c#" i'm stuck in some point.

[Shirahama Kenichi]

Hi...
I'm new to c# and got some problems in rewriting "C" code in "C#".
I got this error message "You can only take the address of an unfixed expression inside of a fixed statement initializer" and i'm not sure whats wrong??? can anybody light my path?
here's the "C" code:

USHORT APIENTRY16 PrtOpenDevice (HFILE * _Seg16 PrtHandle, USHORT PrtDriver);
HANDLE PrtHandle;       /* Printer handle */
USHORT PrtDriver;       /* Logical device driver */
USHORT rc;              /* Return code */
 
PrtDriver = 1;          /* 1st logical device driver */
 
rc = PrtOpenDevice (&PrtHandle, PrtDriver);
 

and this is what i have done so far:

unsafe public partial class Form1 : Form
{
    [System.Runtime.InteropServices.DllImportAttribute("WNTDFPRT.DLL", EntryPoint = "PrtOpenDevice")]
    public static extern ushort PrtOpenDevice([System.Runtime.InteropServices.MarshalAsAttribute(System.Runtime.InteropServices.UnmanagedType.U8)] long *PrtHandle, ushort pPort);
 
    public long PrtHandle = 0;
 
    public Form1()
    {
        InitializeComponent();
        ushort rc = PrtOpenDevice(&PrtHandle, 1);
        MessageBox.Show("return code : " + rc.ToString());
    }
}
 

[Christian Binder]

http://msdn.microsoft.com/en-us/libr...8VS.80%29.aspx
This might help you.

It seems as if you've to do:

fixed(long* pPrtHandle = &PrtHandle) {
  ushort rc = PrtOpenDevice(pPrtHandle, 1);
}
 

instead of ushort rc = PrtOpenDevice(&PrtHandle, 1);

[Shirahama Kenichi]

I try that one, but it returns "PInvokeStackImbalance was detected" instead the fixed-unfixed error.
It seems the "pPrtHandle" contains more than one value.
so the library thinks that "PrtOpenDevice(pPrtHandle, 1)" sending more than two variable.

[Shirahama Kenichi]

@ChBinder
I try something that i haven't yet try:
i change the code in BOLD:

public static extern ushort PrtOpenDevice([System.Runtime.InteropServices.MarshalAsAttribute(System.Runtime.InteropServices.UnmanagedType.U8)] long *PrtHandle, ushort pPort);
 

with:

public static extern ushort PrtOpenDevice(long *PrtHandle, long pPort);
 

thanks to "ChBinder" for the light on "fixed-unfixed error" advice.
[solved]

[Plater]

I would have just said maybe this:

public static extern ushort PrtOpenDevice(ref long PrtHandle, long pPort); 
 

Which I think would do the same thing?