dllimport

I'm trying to export a global variable from a DLL. Foo.h class Foo { public: Foo() {} }; #ifdef PROJECT_EXPORTS #define API __declspec(dllexport) #else #define API __declspec(dllimport) #endif API const Foo foo; Foo.cpp #include "Foo.h" const Foo foo; When I compile the above code, Visual Studio complains: foo.cpp(3) : error C2370: 'foo' : redefinition; different storage class 1> foo.h(14) : see declaration of 'foo' If I use: external const Foo foo; in Foo.h the compiler is happy but then the DLL does not export the symbol. I've managed to export functions with problems, but variables don't

How do I create a Math Input Panel in C#? I have tried to put it into a dll and call it but it just closes right away. #include <stdafx.h> #include <atlbase.h> #include "micaut.h" #include "micaut_i.c" extern "C" __declspec(dllexport) int run() { CComPtr<IMathInputControl> g_spMIC; // Math Input Control HRESULT hr = CoInitialize(NULL); hr = g_spMIC.CoCreateInstance(CLSID_MathInputControl); hr = g_spMIC->EnableExtendedButtons(VARIANT_TRUE); hr = g_spMIC->Show(); return hr; } I call the dll function in C# and the panel pops up but disappears right away. Any suggestions? In your C# project, add a

we use a self-written 32bit C++ DLL from our C# applications. Now we've noticed that when the C# applications are run on a 64bit system, the 64bit runtime is automatically used and of course the 32bit DLL can not be accessed from the 64bit runtime. My question is: is there a way of using the 32bit DLL? If not, if I created a 64bit version of the DLL, would it be easily possible to let the application choose which one to P/Invoke to? I'm thinking of creating two helper classes in C#: One that imports the functions from the 32bit DLL and one that imports from the 64bit DLL, then creating a

After googling, i came to know that Dllimport makes the function available for other modules, is it mandatory to declare function with extern "c" identifier? Also, Dllexport means, Dll itself uses the function while compiling it says. so by default all functions present in DLL are dllexport? __declspec(dllexport) exports a symbol. It makes it available from outside a DLL. __declspec(dllimport) imports a symbol. It practically says "this symbol is not defined in this application, it needs to be imported from a DLL file". You don't have to declare it with extern "C" . If you don't use extern "C"

Using C# and .Net 4.0 in a winforms application: Is it possible to add the UAC shield to a button and retain the buttons background image? How? This is what I'm using at the moment, but it removes the image... [DllImport("user32.dll")] public static extern int SendMessage(IntPtr hWnd, uint Msg, int wParam, int lParam); public static void UACToButton(Button button, bool add) { const Int32 BCM_SETSHIELD = 0x160C; if (add) { // The button must have the flat style button.FlatStyle = FlatStyle.System; if (button.Text == "") // and it must have text to display the shield button.Text = " ";

I need to handle another windows application programatically, searching google I found a sample which handles windows calculator using DLLImport Attribute and importing the user32.dll functions into managed ones in C#. The application is running, I am getting the handle for the main window i.e. Calculator itself, but the afterwards code is not working. The FindWindowEx method is not returning the handles of the children of the Calculator like buttons and textbox. I have tried using the SetLastError=True on DLLImport and found that I am getting an error code of 127 which is "Procedure not found

I know there is a tool called Dll to lib but the developer is asking $1000. I only need to convert one library, once, so its not easy to justify that price. I tried IMPLIB32.EXE, but I just get empty .lib files. How can I accomplish this? Perhaps I can write a simple conversion app? Added1: The Dll's are typically stdcall not cdecl and written in older C like languages NOT C# or .NET or C++. I now need to call them from C++ apps. An example would be the SQLite.dll or zlib.dll. I do not have access to the .lib files for these dll's. Added2: I re-wrote this code for VS2008 http://floodyberry