Understanding Custom Marshaling Part 1

// BasicSample01Interfaces.idl : IDL source for BasicSample01Interfaces
//

// This file will be processed by the MIDL tool to
// produce the type library (BasicSample01Interfaces.tlb) and marshalling code.

import "oaidl.idl";
import "ocidl.idl";

[
	object,
	uuid(BF0DC81A-46FB-4300-88E5-2B8EEB2CEEA1),
	dual,
	nonextensible,
	helpstring("IImmutable Interface"),
	pointer_default(unique)
]
interface IImmutable : IDispatch{
	[propget, id(1), helpstring("property LongValue")] HRESULT LongValue([out, retval] LONG* pVal);
};
[
	object,
	uuid(CCAB57EA-A497-44C0-B0A4-E781B7F47AA9),
	dual,
	nonextensible,
	helpstring("IImmutableObjectFactory Interface"),
	pointer_default(unique)
]
interface IImmutableObjectFactory : IDispatch{
	[id(1), helpstring("method CreateObject")] HRESULT CreateObject([in] LONG InitializationValue, [out,retval] IImmutable** ppIImmutableObjectReceiver);
};
[
	uuid(A5497E3E-1EAA-4E6D-BE52-1AC9DE0D2E61),
	version(1.0),
	helpstring("BasicSample01Interfaces 1.0 Type Library")
]
library BasicSample01InterfacesLib
{
	importlib("stdole2.tlb");
	[
		uuid(5F2C7BC5-0455-422A-B244-D1132C07218C),
		helpstring("Immutable Class")
	]
	coclass Immutable
	{
		[default] interface IImmutable;
	};
	[
		uuid(7324F66F-3F41-4BA9-8426-3D1B5DE4DD9C),
		helpstring("ImmutableObjectFactory Class")
	]
	coclass ImmutableObjectFactory
	{
		[default] interface IImmutableObjectFactory;
	};
};