- to the number of variables in *D. By default all variables
- are returned, but bits may be set in EXCLUDE_CLASSES to
- exclude ordinary, system, and/or scratch variables. */
+ to the number of variables in *D. All variables are returned
+ if EXCLUDE_CLASSES is 0, or it may contain one or more of (1u
+ << DC_ORDINARY), (1u << DC_SYSTEM), or (1u << DC_SCRATCH) to
+ exclude the corresponding type of variable. */