This posting will discuss some of the basics associated with DYNAMIC variables. In particular, we will look at how *LENGTH is set, and how REDUCE and EXPAND impact *LENGTH.

In a subsequent posting we will go further in our discussion of DYNAMIC variables. We will discuss when to use them, when not to use them, and, when not to use EXPAND, REDUCE, and RESIZE (most of the time, contrary to what I have seen many programmers doing).