Both C and COBOL provide language constructs that support the dynamic loading, execution, and deletion of user-written routines. The C fetch() library function dynamically loads a load module that you specify into main storage. The module can be invoked later from a C application (see z/OS XL C/C++ Programming Guide for more information about fetch()). In COBOL, you can use the dynamic CALL statement to dynamically load a load module into main storage. For more information about the CALL statement, see the appropriate version of the programming guide in the Enterprise COBOL for z/OS library.

Both C and COBOL support multiple-level fetches or dynamic calls (for example, Routine 1 fetches Routine 2, which in turn fetches Routine 3, and so on).

User-written condition handlers registered using CEEHDLR can be fetched, but must be written in the same language as the fetching language.