The following figure shows the syntax of SysQueryClassList:

Syntax:  SysQueryClassList(stem)

where

stem     Name of a stem variable in which all registered classes
         are placed.

The following sample code retrieves a complete list of registered objects:

/* */
call RxFuncAdd 'SysLoadFuncs', 'rexxutil', 'SysLoadFuncs'
call SysLoadFuncs

SysQueryClassList('Class_list.')
do cnt = 1 to Class_list.0
  say Class_list.cnt
end