To enable the structure to be defined at runtime, an empty dynamic structure variable must be declared at compile time, using the type DYNSTRUCT:

MAP1 ds, dynstruct   ! scalar dynamic structure

MAP1 DS2, DYNSTRUCT  ! another

As with other built-in types, the type name is case insensitive.

Dynstructs are similar to dynamic X variables (X,0), except that they may be associated with—i.e. bound to—a dynamic structure definition. Until then, the structure is considered "uninitialized".