Interop Question with Unmanaged C++

[Zach]

I have both an unmanaged DLL written in C++, and a Windows Forms
application from which I'm trying to use the services of the unmanaged
DLL. I seem to have everything set up correctly, but I'd really like
to be able to debug into the unmanaged DLL. Here's how I have things
setup.

C++ file:


extern "C" {
DWORD_PTR __declspec(dllexport) TestFunction(LPCWSTR lpszParam);
}

DWORD_PTR __declspec(dllexport) TestFunction(LPCWSTR lpszParam)
{
OutputDebugString(L"Hello\n");
return -1;
}



C# file:
internal static class TestInterop
{
[DllImport("UnmanagedModule.dll")]
public extern static System.UIntPtr TestFunction(string Param);
}

internal class SomeOtherClass
{
public void InvokeTheMethod()
{
UIntPtr Handle = TestInterop.TestFunction("Hello");
}
}



When I step into TestInterop.TestFunction() i'd like to actually have
the debugger walk into my code. But, for whatever reason it doesn't
seem to be working. Oddly enough, in my Output window I don't see any
mention of the fact that it's loading my module or its symbols.
Moreover, the OutputDebugString() in my C++ code doesn't ever appear in
my output window either, the only way I know something is happening is
because I change change the value that gets returned in my C++ code,
and when I step over the function in C# the value is always whatever
I'm returning from the C++ code.


So, what is going on here? Is it even possible to debug across
managed/unmanaged boundaries? And why don't the OutputDebugString()
from unmanaged code show up in my output window?

Thanks

 

[Willy Denoyette [MVP]]

You have to enable umanaged debugging in the debug properties of your
project.

Willy.

|I have both an unmanaged DLL written in C++, and a Windows Forms
| application from which I'm trying to use the services of the unmanaged
| DLL. I seem to have everything set up correctly, but I'd really like
| to be able to debug into the unmanaged DLL. Here's how I have things
| setup.
|
| C++ file:
|
|
| extern "C" {
| DWORD_PTR __declspec(dllexport) TestFunction(LPCWSTR lpszParam);
| }
|
| DWORD_PTR __declspec(dllexport) TestFunction(LPCWSTR lpszParam)
| {
| OutputDebugString(L"Hello\n");
| return -1;
| }
|
|
|
| C# file:
| internal static class TestInterop
| {
| [DllImport("UnmanagedModule.dll")]
| public extern static System.UIntPtr TestFunction(string Param);
| }
|
| internal class SomeOtherClass
| {
| public void InvokeTheMethod()
| {
| UIntPtr Handle = TestInterop.TestFunction("Hello");
| }
| }
|
|
|
| When I step into TestInterop.TestFunction() i'd like to actually have
| the debugger walk into my code. But, for whatever reason it doesn't
| seem to be working. Oddly enough, in my Output window I don't see any
| mention of the fact that it's loading my module or its symbols.
| Moreover, the OutputDebugString() in my C++ code doesn't ever appear in
| my output window either, the only way I know something is happening is
| because I change change the value that gets returned in my C++ code,
| and when I step over the function in C# the value is always whatever
| I'm returning from the C++ code.
|
|
| So, what is going on here? Is it even possible to debug across
| managed/unmanaged boundaries? And why don't the OutputDebugString()
| from unmanaged code show up in my output window?
|
| Thanks
|