Does it make a difference if you load a custom Win32 dll file or a Win64 dll file?

Development Programming & Scripting
1

I have been trying to load a Win32 dll file (test.dll) directly into my plugin StartupModule() function present in

my FTestPlugin: public ITestPlugin class

the way I’m loading the dll is:

void FTestPlugin::StartupModule()
{

FString DllFilename = FPaths::ConvertRelativePathToFull(FPaths::Combine(*FPaths::GameDir(),
		 TEXT("Binaries"), TEXT("Win64"), TEXT("test.dll")));

	void* DLLHandle = NULL;
	DLLHandle = FPlatformProcess::GetDllHandle(*DllFilename);

	UE_LOG(LogPlugin, Error, TEXT("______Just Before the DLL:%s"), *DllFilename);

	if (DLLHandle == NULL)
	{
		 UE_LOG(LogPlugin, Error, TEXT("_____NULL DLLHANDLE"),);
	}
    else
     {
            UE_LOG(LogPlugin, Error, TEXT("_____Entered DLLHANDLE"),);
      }

}

when I try to load the Win32 dll the DLLHandle is always Null but when I try the Win64 dll I get that it exists (and I can see the output log in UE4 )

I was wondering if there is any way I can get this Win32 dll to load without having to compile my game project in 32 bit build mode

Does any one else have any experience loading dlls directly into a class in Unreal engine 4?

I am still looking through the engine Source code for examples, but the closest one to what I wanted to do was in SimplygonMeshReduction.cpp (starting in line 328)

any suggestions or ideas are welcome

2

The short answer is that it can be done, BUT it’s not trivial. It’s going to go through something called COM to pass messages to a 32 bit process, so to make up for it being complicated, it’s also going to be slow.

If you need less that 2 Gb or so of texture/audio at once, I’d just go 32 bit.