Exposing a thirdparty DDL with C++ Classes Header globally to Unreal projects

Development Pipeline & Plugins Plugins
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1

Hello Devs,
maybe a repeated topic but after searching for days I am still not enlighted enough…

Assume I have a thirdparty library (a DLL for Windows, a dynlib for MAC OS…),
that exports some Standard C functions, and that is accompanied with a C++ header file
defining higher-level wrapper classes for that Library.

What is all necessary to install this in Unreal (plugins ?) that it is globally available
for new Unreal projects ?

It sounds simple but the most information I got so far is how to CREATE a plugin
inside a project, and the folder trees that are under “Unreal/Engine/PlugIns” is somehat confusing and not really self-explaining. I understand Unreal uses a specific DLL loading mechanism, but overall it is not clear to me where to start…

Any help is appreciated !!
Thanks, Peter

2

Hello, You’d set this up in your plugin’s Build.cs file. The engine code is the best reference (you don’t need a source build, and can have a look at it from the launcher version of the engine)

Create your plugin (Edit > Plugins > New Plugin). Then open up your C++ project in visual studio (or rider) and head over to your plugin’s Build.cs file

Here you’d include your .dll, .lib, .so etc. Check this as a reference

UE_5.5\Engine\Source\Editor\AudioEditor\AudioEditor.Build.cs

		if (Target.IsInPlatformGroup(UnrealPlatformGroup.Windows))
		{
			string PlatformName = "Win64";

			string LibSndFilePath = Target.UEThirdPartyBinariesDirectory + "libsndfile/";
			LibSndFilePath += PlatformName;


			PublicAdditionalLibraries.Add(LibSndFilePath + "/libsndfile-1.lib");
			PublicDelayLoadDLLs.Add("libsndfile-1.dll");
			PublicIncludePathModuleNames.Add("UELibSampleRate");

			RuntimeDependencies.Add("$(EngineDir)/Binaries/ThirdParty/libsndfile/" + PlatformName + "/libsndfile-1.dll");

			PublicDefinitions.Add("WITH_SNDFILE_IO=1");
		}
		else if (Target.IsInPlatformGroup(UnrealPlatformGroup.Apple))
		{
			string PlatformName = "Mac/";
			string LibFilename = "libsndfile.1.dylib";
			string LibFolder = "libsndfile/";
			string LibSndFilePath = Path.Combine(Target.UEThirdPartyBinariesDirectory, LibFolder, PlatformName, LibFilename);

			PublicDelayLoadDLLs.Add(LibSndFilePath);
			PublicIncludePathModuleNames.Add("UELibSampleRate");
			RuntimeDependencies.Add(LibSndFilePath);
			
			PublicDefinitions.Add("WITH_SNDFILE_IO=1");
		}

or this: UE_5.5\Engine\Source\ThirdParty\OpenColorIO\OpenColorIOLib.Build.cs


		if (Target.Platform == UnrealTargetPlatform.Win64)
		{
			string Arch = Target.Architecture.WindowsLibDir;
			string DLLName = "OpenColorIO_2_3.dll";
			string LibDirectory = Path.Combine(BinaryDir, PlatformDir, Arch);

			PublicAdditionalLibraries.Add(Path.Combine(DeployDir, "lib", PlatformDir, Arch, "OpenColorIO.lib"));
			RuntimeDependencies.Add(
				Path.Combine(ProjectBinariesDir, DLLName),
				Path.Combine(LibDirectory, DLLName)
			);

			bIsPlatformAdded = true;
		}
		else if (Target.IsInPlatformGroup(UnrealPlatformGroup.Unix))
		{
3

Thanks a lot, appreciate it !!