| UBindTarget | Holds information for binding functions |
| UBuffer | The UBuffer struct holds information about a resource, usually a chuck of memory |
| UCell | A cell holds a single value |
| UCellCoord | UCell structure for coord type |
| UCellId | Basic type identification |
| UCellNumber | UCell structure for number types |
| UCellSeries | UCell structure for series types |
| UCellWord | UCell structure for word types |
| UDatatype | The UDatatype struct holds methods for a specific class of data |
| UPortDevice | The UPortDevice struct holds methods for a class of input/ouput device |
| USeriesType | The USeriesType struct holds extra methods for series datatypes |
| UThread | The UThread struct stores the data specific to a thread of execution |