A Note About Terminology
The Essential Tools Module provides input and output classes that let you save and restore objects. These classes are:
*RWFileRWFile lets you save and restore objects to a file.
*RWvostream — Classes derived from RWvostream, such as RWpostream, RWbostream, and RWeostream, are used to save objects.
*RWvistream — Classes derived from RWvistream, such as RWpistream, RWbistream, and RWeistream, are used to restore objects.
To keep our explanations simple, we'll refer to all of these input and output classes as streams. For a discussion of the trade-offs in using RWvostream and RWvistream versus RWFile, see Chapter 5 and Chapter 10.