Re: Cannot marshal 'return value'

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Thanks for the suggestion.
It errors with
A call to PInvoke function 'DLLTest!DLLTest.Q::DiskSaveFooter' has
unbalanced the stack. This is likely because the managed PInvoke signature
does not match the unmanaged target signature. Check that the calling
convention and parameters of the PInvoke signature match the target unmanaged
signature.

I get this error message on the
IntPtr ptr = qn.DiskSaveFooter("mis1", "", "000:000"); line.

I think that Delphi's native strings are single-byte strings, whereas
..NET's are UTF-16 which may be affecting things but i get the above error
message when i define the return type as anything other than char[]

Does this help?



"G Himangi" wrote:

It may work if you define the function as

[DllImport("qn.dll",
CharSet=CharSet.Ansi,CallingConvention=CallingConvention.StdCall)]

public static extern IntPtr DiskSaveFooter(string missionname, string
qlffilename, string id);

and then.....

IntPtr ptr = qn.DiskSaveFooter("mis1", "", "000:000");
char* charArray = (char*)ptr;

this requires unsafe code though.

Or you can use Marshal.Copy to copy the contents of the ptr to a char/byte
array.

---------
- G Himangi, Sky Software http://www.ssware.com
Shell MegaPack : GUI Controls For Drop-In Windows Explorer like Shell
Browsing Functionality For Your App (.Net & ActiveX Editions).
EZNamespaceExtensions.Net : Develop namespace extensions rapidly in .Net
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rapidly in .Net
---------



"ShaunO" <ShaunO@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote in message
news:941ABD0B-C05C-4636-A2D9-8F247D252E54@xxxxxxxxxxxxxxxx
Hi,
I am trying to call an old Delphi .dll

// DELPHI definition (should return an array of 256 chars)
function DiskSaveFooter(missionname,qlffilename,id:pchar):TCharArray;
export;

// My C# definition
[DllImport("qn.dll",
CharSet=CharSet.Ansi,CallingConvention=CallingConvention.StdCall)]

public static extern char[] DiskSaveFooter(string missionname, string
qlffilename, string id);

// My C# Implementation
char []b = new char[256];
b = qn.DiskSaveFooter("mis1", "", "000:000");


I get the ERROR: Cannot marshal 'return value': Invalid managed/unmanaged
type combination.

Any suggestions please?



.

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