Load D shared library on windows x64

[Tofu Ninja]

Do shared libraries work? I am trying to load a D library into a 
D program but Runtime.loadLibrary just returns null for me and I 
am not sure what I am doing wrong.

import std.stdio;
import std.file : exists, getcwd, rename;
import core.thread;
import std.conv : to;
version(tofu_dynamic){
	import core.sys.windows.windows;
	import core.runtime;
	pragma(msg, "Dynamic Link Library");
	HINSTANCE g_hInst;

	export extern (Windows) BOOL DllMain(HINSTANCE hInstance, ULONG 
ulReason, LPVOID pvReserved) {
	    switch (ulReason) {
	        case DLL_PROCESS_ATTACH:
	            writeln("DLL_PROCESS_ATTACH");
	            Runtime.initialize();
	            break;

	        case DLL_PROCESS_DETACH:
	            writeln("DLL_PROCESS_DETACH");
	            Runtime.terminate();
	            break;

	        case DLL_THREAD_ATTACH:
	            writeln("DLL_THREAD_ATTACH");
	            return false;

	        case DLL_THREAD_DETACH:
	            writeln("DLL_THREAD_DETACH");
	            return false;

	        default:
	    }
	    g_hInst = hInstance;
	    return true;
	}

	pragma(mangle, "rti_start") export void rti_start(){
		writeln("rti start :)");
	}

} else {
	void main(string[] args) {
		uint id = 0;

		while(true) {
			if(exists("graph.dll")){
				auto name = "rti." ~ id.to!string ~ ".dll";
				rename("graph.dll", name);
				id++;
		      	     	loadLib(name);
			}
			Thread.sleep(dur!("seconds")(1));
		}
	}

	static void loadLib(string dllName) {
		import core.sys.windows.windows;
		import core.runtime;
		Thread.sleep(dur!("seconds")(1));
		writeln("Start Dynamic Link to ", dllName, "...");
		HMODULE h = cast(HMODULE) Runtime.loadLibrary(dllName);
	  	if (h is null) {
	  		writeln("error loading");
	  		return;
	   	}

	 	scope(exit){
			if (!Runtime.unloadLibrary(h))
	 			writeln("error freeing dll");
	   	}

		FARPROC fp = GetProcAddress(h, "rti_start");
		if (fp is null) {
			writeln("error loading symbol rti_start");
			return;
		}
		
		auto fun = cast(void function()) fp;
		fun();
		writeln("End...");
	}
}