Building and using AMODE 64 dynamic link libraries (DLLs)

The z/OS dynamic link library (DLL) facility provides a mechanism for packaging programs and data into program objects (DLLs) that can be accessed from other separate program objects. A DLL can export symbols representing routines that may be called from outside the DLL, and can import symbols representing routines or data or both in other DLLs, avoiding the need to link the target routines into the same program objects as the referencing routine. When an application references a separate DLL for the first time, it is automatically loaded into memory by the system.

An application that has been compiled and linked to be AMODE 64 uses the XPLINK linkage convention, which is automatically enabled for DLL support. There is no distinction between DLL code and non-DLL code as there is for AMODE 31 applications.

This chapter defines concepts and shows how to build DLLs and DLL applications.