Chapter 1

}
};
}
};
}
version_no = 1;
display_name = "Loopback";
default_data = "";
opaque_data = "0";
Let's go through this step by step:
� The resource file is named after the DLL 3rd UID – 101F8B54.rss. This is a
requirement of the ECOM framework. If the two don't match, then my DLL will not be
loaded.
� I include RegistryInfo.rh as this defines the resource structures ECOM depends
on.
� I declare a REGISTRY_INFO structure to describe the DLL.
� Its first entry is dll_uid, which I set to the GDPLOOP.DLL 3rd UID.
� Its second entry is interfaces, which I set to an array of INTER-FACE_INFO
resources.
� Each INTERFACE_INFO resource defines the registration information for the interface.
I set the interface_uid to the GDP interface UID, 0x101F8B52.
� The implementations member is set to an array of IMPLEMENTATION_INFO
structs.
� I set the implementation_uid to the UID of the loopback implementation, and set
the version_no, display_name, default_data and opaque_data fields
appropriately.
The result is a resource file that describes this DLL as having one implementation of the
GDP interface.
When ECOM loads a DLL in response to a request, it needs to be able to create the right
implementation. The key to this is the Implementa tionGroupProxy() function in
gdploop.cpp:
const TImplementationProxy ImplementationTable[] =
{
{{0x101f8b53}, CGdpLoopback::NewL},
};
EXPORT_C const TImplementationProxy* ImplementationGroupProxy
(TInt& aTableCount)
{
aTableCount = sizeof(ImplementationTable) /
sizeof(TImplementationProxy);
return ImplementationTable;
}