Call a C dll from C#

[Peter Kirk]

Hi

how do I call functions in a DLL written in C from C#.
Eg. in Java it is necessary to use jni - is there something similar in C#?

Thanks,
Peter

 

[Guest]

Use interop for this. Details are here
http://samples.gotdotnet.com/quickstart/howto/doc/Interop/Interop_Overview.aspx

how do I call functions in a DLL written in C from C#.
Eg. in Java it is necessary to use jni - is there something similar in C#?

--
WBR,
Michael Nemtsev :: blog: http://spaces.msn.com/laflour

"At times one remains faithful to a cause only because its opponents do not
cease to be insipid." (c) Friedrich Nietzsche

 

[Michael C]

Hi

how do I call functions in a DLL written in C from C#.
Eg. in Java it is necessary to use jni - is there something similar in C#?

Here's an example

using System.Runtime.InteropServices;

[DllImport("kernel32", EntryPoint= "GetComputerNameA")]
private static extern int GetComputerName(String lpBuffer, ref int nSize);

 

[Michael C]

Hi

how do I call functions in a DLL written in C from C#.
Eg. in Java it is necessary to use jni - is there something similar in
C#?

Here's an example

using System.Runtime.InteropServices;

[DllImport("kernel32", EntryPoint= "GetComputerNameA")]
private static extern int GetComputerName(String lpBuffer, ref int nSize);

Oops, that wouldn't actually work because you can't pass a string in like
that but substitute a byte array or string builder and it would.

 

[Leon Lambert]

If you are using .Net 2.0 and VS2005 its a lot easier to deal with
interfacing managed code with unmanaged code. It supports pragmas for
switching back and forth.
#pragma managed
#pragma unmanaged

This way you can write an managed C++ interface dll and just include the
..h files from the C code. Inside the the dll you can pretty much write
managed code while using the unmanged classes and methods. It magically
figures out how to do the marshaling for you.
From C# you can just use the dll and call the methods directly since
they are managed and you don't need to use pInvoke. There is also a
speed benefit for doing this because the compiler optimizes the marshaling.

I figured a lot about this by looking into the "#pragma managed" help
documentation and other links that VS2005 provided.

Hope this helps.
Leon Lambert