The third field of every Motif resource record holds the name of a Motif representation type. Motif representation types, like Xt representation types, know how to convert resource values into a different C language representation. Motif associates all its representation types with converters that convert data from one C data type (for example, a String) to another (for example, an int).
Motif representation types have the XmR prefix.
You should become familiar with the predefined Motif representation types. You should also know how to create your representation types when conditions warrant.