The objects in the syntax files are not structured the same way in all the SDF-A versions. It is therefore important to read the following notes in order to avoid compatibility problems:
SDF V2.0 and higher and SDF-A V2.0 and higher can handle both the old and new formats for the syntax files. SDF-A converts the objects it accesses to the new format. SDF, in contrast, converts the objects only in virtual memory and makes no changes to the syntax files.
Syntax files which are to run under an SDF version < 2.0 must not be created with SDF-A versions
>=2.0.The following function is provided for correcting syntax files with the old format (required under SDF V1.4 and earlier):
If task switch 15 is set, SDF-A (V2.0 or higher) internally loads the program SDF-A-V1, which has the same functionality as SDF-A V1.0D. The syntax of the SDF-A statements then corresponds to that of SDF-A V1.0D, with three exceptions:The default for the SYSTEM-DESCRIPTIONS and GROUP-DESCRIPTIONS operands in the OPEN-CMD-SET statement is *NO instead of *CURRENT, with the result that no reference syntax files are allocated by default. If the reference syntax files are specified explicitly they, too, must have the old format.
System syntax files cannot be created.
The SDF-A statement SHOW is not supported.
If syntax files with the old format generated by SDF-A V1.0D are processed with SDF-A as of V2.0A, the processed objects and the global information are given the new format.
These syntax files can then no longer be used under an SDF version < 2.0.As of SDF-A V4.0 you can select the syntax file format via the DEFINE-ENVIRONMENT statement. Syntax files created and processed with SDF-A V3.0 retain their original format if SYNTAX-FILE-FORMAT=*V3 is specified. Note that a syntax file can never be modified using an earlier SDF-A version than the one in which it was created and stored.