How Do I Call A Function From A Native Compiled Dll, From C++

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I've been looking into this with no avail. I've tried calling a function from a C++ dll (library) WITH an ENTRYPOINT, with no success. It's not an open source .dll, but their is a .NET library for it. I am currently trying to convert the C# library that calls the functions of the C++ .DLL into C++ CLI.
(So... C# library (using dllimport) conversion to C++CLI)
Of course DLLIMPORT doesn't work, and I've looked into

__declspec(dllexport)

&

__declspec(dllimport)

and I'm not getting anywhere. I have read on this to try and gain some clarity, but lost and still reading.

This is a working (C++ CLI) example for the older .DLL before it was updated... but this doesn't have an ENTRYPOINT in it, but the newer one does and i don't know how to add the entrypoint.

This is what the C++ CLI Version (without entrypoint (older version of DLL)) looks like:

XML

typedef int (__cdecl* Connectf)(const char*);
Connectf Connect  = (Connectf)GetProcAddress(LoadLibrary(L"CCAPI.DLL"),"connectConsole");

This is what the C# version of the LIB looks like:

C#

private static extern int connectConsole(string targetIP);
        [DllImport("CCAPI.dll", EntryPoint = "_ZN5CcApi17disconnectConsoleEi", CallingConvention = CallingConvention.Cdecl)]

P.S.: Here's the C++ CLI Library one of my fellow programmers worked on, with little success: http://pastebin.com/0PTw73WZ

and the original C# Library (updated version): http://pastebin.com/ccATzTm8

Thanks for your time.

BaSs_HaXoR

Posted 17-Sep-14 18:37pm

BaSs_HaXoR

Updated 17-Sep-14 18:43pm

v3

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Comments

Sergey Alexandrovich Kryukov 18-Sep-14 1:22am

You don't need to use P/Invoke with C++. But you can, in exact same way as with C#.
Or you can create a mixed-mode project and freely combine managed + unmanaged code.
—SA

BaSs_HaXoR 18-Sep-14 1:56am

Yea, i thought about doing that, but figured that their should be an easier way. Just by calling the function. And also, what about the Entrypoint? How would i get past that?

Thanks for helping.

Sergey Alexandrovich Kryukov 18-Sep-14 2:46am

"Just by calling what"? You first need to have the loaded DLL and get a function, either C++ or C++/CLI way. By the way, LoadLibrary with GetProcAddress will work for unmanaged code. (If you are sure the the DLL you want to use is native.)
I don't understand the problem of ENTRYPOINT. What is that? How can it be important?
—SA

BaSs_HaXoR 18-Sep-14 5:20am

Yes, I'm positive the .dll is native. And an entry point is where control enters a program or piece of code. (wikied) And i know what has to be done, i just don't know how to do it. I know i have to load the dll and call the function... but don't know how to do that in CLI C++ with an Entrypoint. :/

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Richard MacCutchan · Answer 1 · 2014-09-17T21:46:00

The code:

C++

typedef int (__cdecl* Connectf)(const char*);
Connectf Connect  = (Connectf)GetProcAddress(LoadLibrary(L"CCAPI.DLL"),"connectConsole");

shows you how to access the library. The LoadLibrary call loads the DLL into memory and the GetProcAddress call finds the entry point. However if either of these calls fail then it will not work. You should modify it something like:

C++

typedef int (__cdecl* Connectf)(const char*);
HMODULE hModule = LoadLibrary(L"CCAPI.DLL");
if (hModule == NULL)
{
    // throw an error
}
Connectf Connect  = (Connectf)GetProcAddress(hModule, L"connectConsole");
if (Connect == NULL)
{
    // throw an error
}

Then you will at least have some idea of why it is not working.