VC++ import dll command causes error C2872 'ambiguous symbol' in comdefsp.h - Managed C++/CLI Discussion Boards

Thanks Freak30,

I am using Visual Studio 2010. I tried to send string[] in C# to string[] in C++, but not successful

In C#, I used below codes:

C#

[DllImport("DgnShpConverter.dll")]
public static extern Boolean ConvertDgnToShp(string source, string destinationPath, string     shpFileName, string [] strArray);

And in C++ (file DgnShpConverter.dll), I used below codes:

C++

__declspec(dllexport) bool ConvertDgnToShp(const char* sourceFile, const char *destinationPath, const char *shpFileName, string myArray[])
{
    // do something  ....
}

Do you know how to fix this ?

Thanks and kind regards,
Tai

Please check this link Interoperation: C# and native Win32 C++ code; arrays of strings[^]

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Hi Karthik,

Thank you very much. Your link is very useful. I will try it.

Kind regards,

Tai

I have migrated a bunch of C++/CLI code out of my main mixed-mode executable into a DLL but Windows explorer is not showing the details for the DLL. I set them like this in my AssemblyInfo.cpp:

C++

[assembly:AssemblyTitleAttribute("MyDLL")];
[assembly:AssemblyDescriptionAttribute("A cool component")];
[assembly:AssemblyConfigurationAttribute("")];
[assembly:AssemblyCompanyAttribute("My Company")];
[assembly:AssemblyProductAttribute("My Product")];
[assembly:AssemblyCopyrightAttribute("Copyright © My Corp 2013")];
[assembly:AssemblyTrademarkAttribute("")];
[assembly:AssemblyCultureAttribute("")];
[assembly:AssemblyVersionAttribute("2.0.0.0")];

I also have a C# DLL with settings just like this in its AssemblyInfo.cs and they ARE shown in the Details pane of the Explorer Properties dialog.

I suspect I'll need to add a .rc file with VERSIONINFO but was hoping to avoid duplicating info like that (and it's a small hassle to hook into the build).

Has anyone here faced and solved this issue?
John

I'll answer my own question for future visitors. Yes, adding the VERSIONINFO resource was necessary. And, it was easier than I thought - just right-click on Resource Files folder in Solution Explorer, Add > Resource... and select VERSIONINFO.

John

Odd that Microsoft puts their debug annotations into their code now (winnt.h)-does that mean they'll finish testing at the customer premises?

Daniel Kilsdonk

Odd that you did not read http://www.codeproject.com/Messages/1329679/The-Cplusplus-CLI-is-for-managed-and-mixed-mode-Cp.aspx[^] before posting.

Use the best guess

Hello everyone,

so I'm using VC++ 2008 and I've got a large solution made up of several different interconnected projects, some of which are DLL's (no CLR). In one of these DLL's I'm trying to import an EXTERNAL Visual Basic dll using the command #import "C:\path\to\my\DLL\file.dll" . If I use this command in one of my .cpp files, it works. If on the other hand, I use it in one of my .h files, I then get the following compile errors in the files ocidl.h and comdefsp.h. I noticed that the .tlh and .tli files generated by the #import command include the file comdef.h. There are other files in my project that include the file comdef.h. Could this be the reason for the conflict?

VB

Error   1236    "solution_name" error C2872: 'IDropTarget' : ambiguous symbol   C:\Program Files\Microsoft SDKs\Windows\v6.0A\include\ocidl.h   3949
Error   1237    "solution_name" error C2872: 'IServiceProvider' : ambiguous symbol  C:\Program Files\Microsoft SDKs\Windows\v6.0A\include\ocidl.h   6238
Error   1238    "solution_name" error C2872: 'IDataObject' : ambiguous symbol   c:\program files (x86)\microsoft visual studio 9.0\vc\include\comdefsp.h    216
Error   1239    "solution_name" error C2872: 'IDataObject' : ambiguous symbol   c:\program files (x86)\microsoft visual studio 9.0\vc\include\comdefsp.h    216
Error   1240    "solution_name" error C2872: 'IDropTarget' : ambiguous symbol   c:\program files (x86)\microsoft visual studio 9.0\vc\include\comdefsp.h    246
Error   1242    "solution_name" error C2872: 'IMessageFilter' : ambiguous symbol    c:\program files (x86)\microsoft visual studio 9.0\vc\include\comdefsp.h    771
Error   1243    "solution_name" error C2872: 'IMessageFilter' : ambiguous symbol    c:\program files (x86)\microsoft visual studio 9.0\vc\include\comdefsp.h    771
Error   1244    "solution_name" error C2872: 'IServiceProvider' : ambiguous symbol  c:\program files (x86)\microsoft visual studio 9.0\vc\include\comdefsp.h    1041
Error   1245    "solution_name" error C2872: 'IServiceProvider' : ambiguous

since IDropTarget is a type, and it is referenced in ocidl.h, 'ambiguous' implies two definitions for the same, one must not disclude that the two definitions ARE the same and this would point to the common error of an include file, including itself.

An include file should never include itself! But include files are notorious for including themselves vis-à-vis other include files. While it is of poor craftsmanship, it IS promoted in K&R C manual itself when they proscribe something akin to:
#IFNDEF THISFILENOTALREADYREAD
#define THISFILENOTALREADYREAD
....
your h file: 'thisfile'
...
#ENDIF

If this is not the case, kindly submit the result of this search complete solution
'IDropTarget'

Also, there is a switch you can throw that will indicate the include files as they are included. That would be helpful.

Daniel Kilsdonk

I have project which I am compiling with /clr. I have a class like below..

C#

ref class A
{
public:
 void CheckValue(void * test);
 typedef ref struct val
{
 std::string *x;
}val_t;

};

in my implementation I ahve to use something like below..

C#

void A::CheckValue(void *test)
{
 a::val_t^ allVal = (a::val_t^)test;
}

in my main I have used like..

C#

int main()
{
A^ obj = gcnew A();
a::val_t valObj = new std::string("Test");
obj->CheckValue((void*)valObj);
}

I am getting type cast error and two places - obj->CheckValue((void*)valObj); and at obj->CheckValue((void*)valObj); error C2440: 'type cast' : cannot convert from 'void*' to 'A::val_t ^'

This snippet is just to show behavior at my end and I ahve to use it this way only. Earlier I was running it using non /clr so it compiled fine.

Now question I have how can I make this type casting work in C++/CLI type project?

You are mixing the two - managed and unmanaged - void * is unmanaged and val_t is managed. You need to do a conversion in order to get this to work. Here is a similar question:

http://stackoverflow.com/questions/6903208/cli-c-void-to-systemobject[^]

As we know C++ disdains poor typing. Some day it will achieve Pascal or Ada greatness!

Try:
desired_ptrtype newone=static_cast<desired_ptrtype>(voidstarptr)

Daniel Kilsdonk

Getting Access Violation Exception when trying to convert unmanaged array of structures into managed in Vb.Net(VS2010,4.0 framework) in Windows 7 -64 bit mode.
Sample Source Code

<structlayout(layoutkind.sequential, charset:="CharSet.Ansi)"> _
Public Class vb_menu_dotnet
Public level As Short
Public menu_id As String
Public short_desc As String
Public parent_id As String
Public access As Short
Public flag As Short
Public menu_desc As String
End Class

Dim current As IntPtr
Dim outArray As IntPtr
Dim manArray(100) As vb_menu_dotnet

vb_dotnet_get_menu_hierarchy(p_menu_handle, p_apl_id, outArray) //C API call
current = outArray

Dim j As Integer
For j = 1 To 100
manArray(j) = New vb_menu_dotnet()
Marshal.PtrToStructure(current, manArray(j)) //Access Violation Exception

Vijay

You may need to try a VB.NET forum. This is for C++/CLI code.

VB

Dim current As IntPtr
Dim outArray As IntPtr
Dim manArray(100) As vb_menu_dotnet
 
vb_dotnet_get_menu_hierarchy(p_menu_handle, p_apl_id, outArray) //C API call

You have not initialised any of the pointers that you are sending to the C-language library. Take a look at this P/Invoke tutorial[^] for more information.

Use the best guess

Hi ,
whatever database u r acessing or data retrieval policy u might be using for e.g INI file,must be in Read Mode,Try to make it Write protected

Did you actually read the OP's question?

Use the best guess

ASM

Hi ,
whatever database  u r acessing or data retrieval policy u might be using for e.g INI file,must be in Read Mode,Try to make it Write protected

can anyone help me finding the source code or the simulation of the Dual Busy Tone Multiple Access (DBTMA) protocol ????

regards...
Sniff | :^)

A simple Google search[^].

Use the best guess

Thanks alot, but i need a simulation for any BTMA, DBTMA or DUCHA .
i've a similar project based on multi-channel and busy tones.
regards

Well you could always refine the Google search that I created, which was based on the exact content of your question.

Use the best guess

All these search results are papers, but i need a written code

3bood.ghzawi wrote:
i need a written code

Well if you cannot find it by searching the internet then you will have to write it yourself.

Use the best guess

You have the patience of Job on this forum. Smile | :)