Matia's DLL Map

Register a DLL map of the name AssemblyName.DllConfig.xml.

This library is designed to help map a DllImport instruction to a different library using an XML document of the name of the assembly and the .DllConfig suffix.

An Example Program

For a program with the assembly name "MyGlfwWrapper":

using System.Runtime.InteropServices;

namespace MyGlfwWrapper;

public static class Glfw
{
    [DllImport("glfw", EntryPoint="glfwInit")]
    public static extern int Init();
}

public static class Program
{
    public static void Main()
    {
        if (Glfw.Init() < 0) Console.Error.WriteLine("Failed to init GLFW");
    }
}

This program will not work on any system that uses or ships a library that is GLFW but has a different name. For example, the latest on Linux will be called libglfw3.so but on Windows it will be GLFW3.dll. With this library, if we instead create the program as:

using System.Runtime.InteropServices;
using Matia.DllMap;

namespace MyGlfwWrapper;

public static class Glfw
{
    [DllImport("glfw", EntryPoint="glfwInit")]
    public static extern int Init();
}

public static class Program
{
    public static void Main()
    {
        DllMapper.Register(Assembly.GetExecutingAssembly());
        if (Glfw.Init() < 0) Console.Error.WriteLine("Failed to init GLFW");
    }
}

On the project, we would have a Windows.MyGlfwWrapper.DllConfig.xml and a Linux.MyGlfwWrapper.DllConfig.xml.

The Windows.MyGlfwWrapper.DllConfig.xml would look like:

<configuration>
    <dllmap dll="glfw" target="GLFW3.dll" />
</configuration>

But the Linux.MyGlfwWrapper.DllConfig.xml would look like:

<configuration>
    <dllmap dll="glfw" target="libglfw3.so.0" />
</configuration>

During build, due to the nature of the program, we'd want to use the -r (RID) option during build and, run and/or publish/pack. For the "-r win-x64" option we'd want to Link the Windows.MyGlfwWrapper.DllConfig.xml to the output directory as MyGlfwWrapper.DllConfig.xml. But for the "-r linux-x64" option, we'd want to Link the Linux.MyGlfwWrapper.DllConfig.xml to the output directory as MyGlfwWrapper.DllConfig.xml. This will ensure that the Windows build links to the correct library and so will the Linux build, without having to change the native name of the libraries.

A project like this would have a structure such as:

MyGlfwWrapper
|   README.md
|   LICENSE.md
|   MyGlfwWrapper.csproj
|
|___DllConfigs
|   |   Windows.xml
|   |   Linux.xml
|   |   Mac.xml
|
|___src
|   |   Program.cs
|
|___Native
|   
|   |___win-x64
|   |   |   GLFW3.dll
|   |
|   |___mac
|   |   |   libglfw3.dylib
|   |
|   |___linux-x64
|   |   |   libglfw3.so.0

After building this assembly for "-r win-x64", we'd want to see in the output:

out
|   GLFW3.dll
|   MyGlfwWrapper.dll
|   MyGlfwWrapper.exe
|   MyGlfwWrapper.DllConfig.xml

But for "-r linux-x64" we'd want to see:

out
|   libglfw3.so.0
|   MyGlfwWrapper.dll
|   MyGlfwWrapper
|   MyGlfwWrapper.DllConfig.xml

And so on. The only differences should be the origin of the XML file and the native library, with the XML file having the <configuration><dllmap dll="stringUsedInDllImport" target="nativeLibraryName.ext"/></configuration> structure but changing the target string. Adding more <dllmap> lines can be used for other native libraries so that multiple can be used.