To be able to exchange application parts, the start LLMs must be linked beforehand as a link load module (LLM) and be made available in a program library as type L element (see section "Linking LLMs").
The rest of the program units must also be linked beforehand as a link load module (LLM) and be made available in a program library as type L elements, or they must be contained as object modules (OMs) in an object module library (OML) or in a program library as type R elements.
Exchangeable load modules must always be generated in a LOAD-MODULE statement with LOAD-MODE not equal STATIC. If they are loaded in a common memory pool, this must be generated with MPOOL ,...SCOPE=GROUP. If program units or data areas are incorporated in a load module, the LOAD-MODULE operand must be defined as appropriate in the associated PROGRAM or AREA statements.