The first step in creating a SOM class is to define the class and its relationship to other classes. In SOM, a class is defined in a formal specification language, the SOM interface definition language (IDL). IDL has a language-neutral core (appropriate for any programming language) to which some minor extensions have been added to simplify programming in C. IDL supports C and C++ programming languages. The class definition is saved in an ASCII text file with an extension of .IDL.

The second step is to process the IDL file using the SOM compiler to produce a set of language-specific or use-specific binding files for the class. The binding files are then used to build class libraries that can be used by client applications; that is, applications that are to create subclasses or object instances.

Note: Hereafter, any information concerning SOM bindings is specifically geared toward the SOM C-language bindings, as distinguished from other SOM language bindings.