Different DLL names on native dlls for multiple platforms

[jogibear9988]

I try to use a native dll (openssl) on different platforms, and my assembly should also support net 4.7

Now is there a way, to specify different dll names for each platform, but keep the dotnet included native dll resolver?

Problem is, openssl has different dll names on each platform.

And I don't like to copy the the whole imports.

[dotnet-policy-service]

Tagging subscribers to this area: @dotnet/interop-contrib
See info in area-owners.md if you want to be subscribed.

[jkotas]

my assembly should also support net 4.7

There is no good built-in way to do this in .NET Framework 4.7.

The best you can do is to multi-target your assembly: one build configuration that targets Windows .NET Framework 4.7, and one configuration that targets modern .NET and takes advantage of all new APIs as appropriate (including System.Runtime.InteropServices.NativeLibrary APIs designed for this scenario)

It is the approach that we use to solve issues like this in packages published by this repo. For example, System.Data.Odbc package includes multiple configurations: https://github.com/dotnet/runtime/blob/main/src/libraries/System.Data.Odbc/src/System.Data.Odbc.csproj#L4. The Unix configurations have custom native library loading logic: https://github.com/dotnet/runtime/blob/main/src/libraries/Common/src/Interop/Unix/Interop.Odbc.cs#L17-L36 .

[huoyaoyuan]

On .NET Core, you can use SetDllImportResolver or AssemblyLoadContext.ResolvongUnmanagedDll to handle the name difference on different operating systems.

[MichalPetryka]

For .Net Framework/Standard you can also PInvoke into LoadLibrary/dlopen instead and then call the method via cached function pointers like if you'd use NativeLibrary.