Writing your exit

File Manager does not supply a default scrambling exit. If you plan to use a scrambling exit you must provide one or more for your installation.

Any exit you provide must be in the form of a load module, in any load library available to File Manager, either by a STEPLIB DD statement, or in LINKLIST, or LPALIST. If File Manager attempts to load an exit and is unable to find it, an error message is displayed.

You can write your own exit in any high level language, for example, COBOL, PL/I, or High Level Assembler. Sample exits for COBOL, PL/I, and HLASM are provided in FMN.SFMNSAM1. They are:
FMNSCXEA
Sample HLASM exit
FMNSCXEC
Sample COBOL exit
FMNSCXEP
Sample PL/I exit
These samples perform a simple scrambling algorithm of changing all uppercase characters to 'A', all lowercase characters to 'a', and all numbers to '1'. They are designed purely to demonstrate the capabilities of an exit. Refer to the prolog in each sample for more information about coding your exit.
Copybooks providing the scrambling exit control blocks for COBOL, PL/I, and HLASM are distributed in the File Manager macro library, FMN.SFMNMAC1. They are:
FMNSCXCA
Control block for HLASM programs
FMNSCXCC
Control block for COBOL programs
FMNSCXCP
Control block for PL/I programs
These copybooks are described in Exit control block description. See Using the scrambling exit control block for information on how to write your exit using the copybooks.
Note:
  1. The File Manager I/O exit does not support 24-bit addressing mode.
  2. File Manager supports an exit written in any supported release of COBOL and PL/I.
  3. File Manager provides information concerning the input and output field formats as described by the exit control block. See Exit control block