how to call C++ lib file from C#

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sunny - 06 Jul 2004 03:53 GMT

Dear everyone:
I know I can call a dll by c# like this:

using System.Runtime.InteropServices;
[DllImport("user32.dll")]
public static extern int MessageBox(int hWnd, String text,
String caption, uint type);

but now I want to call a lib file created by VC6.0,for example "a.lib".
Could anybody tell me how to do it?
Thanks!

Tom

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Klaus H. Probst - 07 Jul 2004 20:06 GMT

Nope. It implies the ability to link statically, and .NET won't do that.

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Klaus H. Probst, MVP
http://www.vbbox.com/

> Dear everyone:
> I know I can call a dll by c# like this:
[quoted text clipped - 9 lines]
>
> Tom

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Richard Grimes [MVP] - 02 Aug 2004 20:14 GMT

> Dear everyone:
> I know I can call a dll by c# like this:
[quoted text clipped - 7 lines]
> "a.lib". Could anybody tell me how to do it?
> Thanks!

you have two options:

1) use unmanaged C++ to expose the lib functions as exported (unmanaged) DLL
functions
2) use managed C++ to expose a managed class

Managed C++ can use unmanaged .lib files, which is why #2 works, however,
there are issues with mixing managed and unmanaged code in a library
assembly (caused by the Win32 DLL loader holding various locks which could
cuase a deadlock). #1 is the safest option.

Richard

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alanrn - 03 Aug 2004 01:21 GMT

So, how is option #1 accomplished?

.ARN.

> > Dear everyone:
> > I know I can call a dll by c# like this:
[quoted text clipped - 20 lines]
>
> Richard

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Richard Grimes [MVP] - 08 Aug 2004 17:37 GMT

>> 1) use unmanaged C++ to expose the lib functions as exported
>> (unmanaged) DLL functions
>
> So, how is option #1 accomplished?

Well, if you have a lib that provides this function:

bool test_func(int param1, char* param2);

you create a DLL with this function:

extern "C" __declspec(dllexport) bool Test_Func(int param1, char* param2)
{
return test_func(param1, param2);
}

Richard

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how to call C++ lib file from C#

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