Using a .lib file in a C# program

Question

I have a header file and a .lib file created using C++.

Now I want to use it in a C# program. Is this possible?

Tenney

possible duplicate of How to use *.lib file in C# application? – Attemper

Answer 1

Not directly. You can interoperate with unmanaged DLLs via P/Invoke, or mixed-mode assemblies using C++/CLI. Either way, you'll have to create a wrapper project, or recompile the original .lib (if you have the sources) into DLL.

Maximamaximal

Answer 2

I don't know about a .lib file. But I do know if you compile your code as a DLL you can consume it as unmanaged code.

To do this you'll need to reference

System.Runtime.InteropServices

and you will need to define the method you want to use and give it the DllImport attribute. Something like this:

[DllImport("MyCPPDll.dll")]
public void SomeMethod(int someParameter);

Here are a few links that should help point you in the right direction:

http://msdn.microsoft.com/en-us/library/26thfadc(v=vs.100).aspx

http://msdn.microsoft.com/en-us/library/system.runtime.interopservices.dllimportattribute(v=vs.100).aspx

Forgive

Answer 3

C# compiler does not need nor use .lib files.

Important thing to note is that there are two flavors of .lib files:

1. Static libraries

   Those are meant to be statically linked to a C/C++ program. They are usually quite large. If this is what you have, and if you don't have a matching .dll file, then you are out of luck since static libraries cannot be directly used from a C# program.

2. Import libraries

   Those contain only function import data for C/C++ linker to consume while building the executable which uses the actual dynamically linked library (DLL). They are usually easy to spot because they are smaller in size and contain a bunch of __imp__ prefixed function names at the start of file.

In any case, the header file has all the information needed to call the functions from a C/C++ library regardless of its type.

If the library you have is static, you will first have to create a C/C++ DLL project which wraps every function from this static library in order to be able to use it from a C# program. How to do that will largely depend on the library API design and the language it was written in (C or C++).

If you already have a DLL, then all you have to do is create a (usually static) C# class with all constants, structures, and functions listed in the header file marshaled properly, and mark those library functions with [DllImport] to tell C# compiler which DLL they come from.

Finally, when creating a C# program which will use the library, you must also match the platform target -- set x86 or x64 explicitly instead of Any CPU depending on what your library platform target is.

Adin

Answer 4

There's not a traditional linker to let you import the lib. Your best bet is to compile to a COM library and use interop to use it.

Advisable