A subcommand handler can reside in the same module (EXE or DLL) as an application, or it can reside in a separate dynamic link library. An application that runs REXX procedures with RexxStart should use RexxRegisterSubcomExe to register subcommand handlers. The REXX interpreter passes commands to the application subcommand handler entry point. Subcommand handlers created using RexxRegisterSubcomExe are available only to REXX programs called from the registering application.
The RexxRegisterSubcomDll interface creates subcommand handlers that reside in a dynamic link library. Any REXX program using the REXX ADDRESS instruction can access a dynamic link library subcommand handler. A dynamic link library subcommand handler can also be registered directly from a REXX program using the RXSUBCOM command.