External Product Interface › CA7MVS—Sample CA 7 Interface Routine › CA7MVS Implementation

CA7MVS Implementation

The CA7MVS REXX program uses the ADDRESS EPI environment to define a virtual terminal, enable it, and log it on to CA 7. When a user wants to execute a sequence of input commands, they are stacked in global variables (uniquely named for each address space) until an EXECUTE command is encountered.

The CA 7 virtual terminal is then enqueued on exclusively, and the input data is entered onto the screen. Responses are scrolled through to retrieve all output and are placed in the REXX external data queue. The virtual terminal is dequeued after completion.

The CA7MVS program handles scrollable output such as that from LACT, LPRRN, LJOB, and most other list commands (Lxxx) in a special way, as follows:

• All blank lines are removed.
• Page number lines are removed.
• Duplicate column header lines are removed from page 2 and all subsequent pages.

This causes the returned output to start with a single set of column header lines, followed by detail data lines without intervening headers or blank lines, followed optionally by a command completion line from CA 7.

The intended use for the CA7MVS is primarily for command/response type applications, where a single command is used to inquire CA 7 (non-interactive commands). Commands that invoke an interactive dialog (such as QJCL) can be issued through CA7MVS, but will leave the terminal unusable for other callers of CA7MVS in that case.

The CA7MVS program does allow multiple users to issue non-interactive commands using a single CA 7 virtual terminal. CA7MVS takes care of the details of sharing the virtual terminal in such case.