All the exits used on any system in a MAREN network must be made available as object modules in a module library. This library must be assigned using the link name MARENLIB before the programs MARENCP and MARENUCP are called. When MAREN is started up, these modules, if they are available, are dynamically linked to the control program MARENCP and to MARENUCP via the BIND macro. If one or all of the exits are missing from the object module library, then MAREN starts normally and no error message is issued. If an exit routine is changed and added to the object module library, this change only takes effect when the object module library is closed.
The exits can be switched during ongoing operation by checking whether the assigned object module library has been modified in the case of each request in MARENCP, MARENUCP and MARENADM. When a modification takes place, all loaded exits are reloaded. If an error occurs with the BIND macro (e.g. if the element is locked), BIND is repeated.
If the MARENADM administrator program is used with direct access to the MAREN catalog, a number of the exit routines are also executed. In this event, however, it is not necessary to assign the exit library explicitly as MARENADM fetches the name via a call to the control program. If this library is under a user ID other than the administrators user ID, it must be cataloged with USER-ACCESS=*ALL-USERS.