COM in plain C, Part 4

// The IDL file for IExample3.DLL
//
// {6C5A4C1A-87B3-44c1-8286-78000B2173EF} = Type library's GUID
// {6AFACEB2-9298-4d4b-80C1-F027C07B1A1E} = IExample3 object's GUID
// {CFADB388-9563-4591-AABB-BE7794AEC17C} = IExample3 VTable's GUID
// {F69902B1-20A0-4e99-97ED-CD671AA87B5C} = Ports Collections's GUID

[uuid(6C5A4C1A-87B3-44c1-8286-78000B2173EF), version(1.0), helpstring("IExample3 COM server")]
library IExample3
{
	importlib("STDOLE2.TLB");

	[uuid(F69902B1-20A0-4e99-97ED-CD671AA87B5C), helpstring("ICollection object"), oleautomation, object]
	interface ICollection : IDispatch
	{
		[propget, id(1), helpstring("Returns the count of items in the collection")] 
		HRESULT Count([out, retval] long *);
		[propget, id(DISPID_VALUE), helpstring("Returns the item (at the specified index) of the collection")] 
		HRESULT Item([in] long, [out, retval] VARIANT *);
		[propget, id(DISPID_NEWENUM), restricted] 
		HRESULT _NewEnum([out, retval] IUnknown **);  
	};

	[uuid(CFADB388-9563-4591-AABB-BE7794AEC17C), dual, oleautomation, hidden, nonextensible]
	interface IExample3VTbl : IDispatch
	{
		[helpstring("Sets the test string.")]
		[id(1), propput] HRESULT Buffer([in] BSTR);
		[helpstring("Gets the test string.")]
		[id(1), propget] HRESULT Buffer([out, retval] BSTR *);
		[helpstring("Gets the enumeration for our hardware ports.")]
		[id(2), propget] HRESULT Ports([out, retval] IDispatch **);
	};

	[uuid(6AFACEB2-9298-4d4b-80C1-F027C07B1A1E), helpstring("IExample3 object."), appobject]
	coclass IExample3
	{
		[default] interface IExample3VTbl;
	}
}