Automatic RWClassIDs are created in a systematic way from unused RWClassIDs in the range 0x9200 to 0xDAFF. There are 18,687 possible such RWClassIDs, so only extraordinary programs can possibly run out. However, we are used to dealing with extraordinary customers, so we feel we must warn you: you will not be able to build and use more than 18,687 different classes with automatically generated RWClassIDs in any one program. 16-bit DLLS will also accumulate automatic RWClassIDs while they are loaded in memory

Note that this implies nothing about the total number of objects of each class that you may have. That number is limited only by the requirements of your operating system and compiler. Of course, you also have access to the full set of RWClassIDs below 0x8000—that is, 32,767 more possible RWCollectable s—but they will not be automatically generated. You must specify them manually.