At library linkage time, if either half of a linkage operation is an EXPORTING or IMPORTING connection library, the MCP checks that only a one-way import/export relationship is being established. If the linkage operation would produce a two-way import/export relationship, in conjunction with existing library and IPC relationships, the linkage fails.

Also, if either half of a linkage operation is an EXPORTING or IMPORTING connection library, the importing side of the connection must not be a server library, which is a library established by the FREEZE statement.

You can avoid creating two-way import/export relationships by linking EXPORTING or IMPORTING connection libraries first and then closing the loop with a server library linkage or with a connection library linkage not specifying EXPORTING or IMPORTING. This concern can be addressed by using only EXPORTING and IMPORTING connection libraries for the library linkages within an application.