Release 10.1A: OpenEdge Getting Started:
Object-oriented Programming

Using handles

HANDLE variables and temp-table fields are weakly-typed. A handle can be used as a reference to virtually any kind of built-in or user-defined object (except a class), including a procedure, a visual object, a data management object such as a buffer or query, and so on. Because handle references are set at run time, Progress does not (and indeed cannot) verify much of anything about how a handle is used at compile time. As a result, you can easily use a handle improperly, for example, invoking a buffer object method on a procedure handle object—an error that Progress can only catch at run time.