using cpp dll in c# code

Question

I'm trying to use native c++ dll inside a c# application.

I followed this article to get started.

Its working fine while the dll using only c files (like in the tutorial), but when using cpp files I cant make it work.

using the dumpbin tool I can see that my exported function names changed. for example a function call 'next' changed to '?next@@YAHH@Z' and when I'm trying to call it in the c# code it cant find it.

my dll code is:

__declspec(dllexport)
int next(int n)
{
    return n + 1;
}

the c# code

[DllImport("lib.dll", CallingConvention = CallingConvention.Cdecl)]
    extern static int next(int n);

its the same code while using c file or cpp files

Thanks in advance Amichai

Please post your code. – Wagner DosAnjos Nov 03 '16 at 06:29 — Wagner DosAnjos, Nov 03 '16 at 06:29
i dont understand what you mean by cpp – Vijunav Vastivch Nov 03 '16 at 06:35 — Vijunav Vastivch, Nov 03 '16 at 06:35
@wdosanjos, thanks. i added my code to the question. – amichai Nov 03 '16 at 06:35 — amichai, Nov 03 '16 at 06:35
What about your C# code? – Wagner DosAnjos Nov 03 '16 at 06:37 — Wagner DosAnjos, Nov 03 '16 at 06:37
@wdosanjos, i added the c# code too. Thanks. – amichai Nov 03 '16 at 06:38 — amichai, Nov 03 '16 at 06:38

score 2 · Accepted Answer · edited May 23 '17 at 10:29

2

What you are attempting to do is to make a trampoline function, to externalize the use of your C++ objects.

What you are experiencing is called symbol mangling. It is a c++-specific way of naming the symbols (like the functions) in a dynamic library and an executable, to enable polymorphism.

You have to specify that you want to cancel the mangling effect by using an extern "C" statement in your library code, just like this:

extern "C" __declspec(dllexport)
int next(int n)
{
    return n + 1;
}

More on this here: Exporting functions from a DLL with dllexport

edited May 23 '17 at 10:29

Community

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1

answered Nov 03 '16 at 06:50

Christopher J.

1,154
1
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21

1

Thanks a lot. helpedme very much – amichai Nov 03 '16 at 07:00

score 0 · Answer 2 · answered Nov 03 '16 at 06:47

0

Please provide the Entry Point

An example below

[DllImport("lib.dll", CallingConvention = CallingConvention.Cdecl, EntryPoint = "next", CharSet = CharSet.Ansi)]
static extern int next(int n);

Hopefully It helps.

answered Nov 03 '16 at 06:47

Abhishek Kumar

342
5
22

using cpp dll in c# code

2 Answers2