The functionality offered by the MDL API is split into so-called API components.
Each component gives access to some aspect of the MDL API. The basic interface mi::neuraylib::INeuray gives access to these API components via its get_api_component()
methods.
This page here lists all API components. Note that some API components are always available (e.g., configuration interfaces), while other API components might only available while the MDL API is running.