This section describes how to define and store exit programs.
It is the administrator's responsibility to ensure that user exit programs do not have adverse effects on Super Natural!
This section covers the following topics:
There are two kinds of exit programs in Super Natural:
User exits
System exits
User exits can be invoked from up to ten places within a transaction at run time. The user defines which exits he wants to use, the location and any parameters. An exit can be any of the following:
Subprogram invoked by CALL statement
Natural program
Natural subprogram
Natural subroutine
Natural map
User exits which are Natural objects must be stored in the steplib SYSTEM or in the current user's private library.
Super Natural recognizes the exit type and
automatically generates the relevant Natural statements such as
FETCH RETURN, CALLNAT or
PERFORM and passes parameters.
Note:
You can prevent the modification of exits in transactions in a
public library or in transactions which will be used as a superfile using the
LOCK command.
When you are writing a user exit program, consider the following points:
An exit program must be one of the following:
An external program (e.g., COBOL or ASSEMBLER subprogram) callable
by a Natural CALL
statement.
Or:
One of the Natural object types listed in the previous section.
Parameters must correspond with the call of the external
program as used in the CALL statement; or with the
parameter list used in the Natural module
If the exit program requires parameters, the user must specify them
manually using the Exit Specification function.
To connect a user exit program with a file
Change the file options as described in the section Exit Specification in the section Files.
Do not forget to provide the users with the program names of the user exits available to them, and tell them which parameters are to be passed to the subprogram.
The object modules ofNatural programs, subprograms, subroutines, or maps can be stored as follows:
In the steplib SYSTEM (FUSER or FNAT) - all users of Super Natural can access these modules from their private libraries and from any common library. This is recommended in most cases.
Or:
In the private Super Natural libraries of selected users - only the selected users can use these user exits. IfSuper Natural is running under Natural Security, the private library of each of the selected users must be defined to Natural Security.
Or:
In the appropriate common library if the transaction from which the module is called is either executed in a common library or was added in a common library.
Note:
When you copy a transaction which uses user exits, you must make
sure that the user exit object modules are available in the target environment
as described above.
For information on storing object modules of external (non-Natural) programs, contact your Natural administrator or see the Natural documentation.
You use system exits to take control at a certain point in Super Natural. The following system exits are supplied with Super Natural in source code:
| ENTRY | Program invoked as entry routine for the Super Natural session. |
| EXIT | Program invoked as exit routine when the Super Natural session is terminated. |
| SHEXIT | Program which takes over if the user presses. |
| SNERRU | Program invoked by error routine SNRTE. SNERRU can be modified to handle specific error conditions. For example, you can use SNERRU to give the user additional information or instructions when an error occurs. |
| SPRJEU | Natural subprogram which is executed once for every job card prior to the submission of a batch job. |
| SPPARM | Subprogram to define environment
specific parameter settings. Parameters include: The submission indicator for batch job submission (RJE or NPR). Com-plete hardcopy support - default printer number generation or prompting for destination (default). Common library prefix character - only change at installation. Layout prefix character - only change at installation. |
You can modify these user exits if required.
