The SEE function has no CONTINUATION-MODE. It is a display-only function; however, it can serve as the NEW-TRANSACTION-MODE for various other functions, such as NXT, DUP, CHG, or DEL functions. The NXT function has no NEW-TRANSACTION-MODE of its own. It is to be used after a successful SEE function or CHG function. If, however, it is not preceded by one of those functions, it will attempt to start a browse as if it had been preceded by a SEE function.

Entry point for the xxxNXT function. Because NXT has no NEW-TRANSACTION-MODE, control always arrives here from a prior SEE or CHG transaction context held in the TWA (Task Work Area). The NXT function begins. Because NXT has no new-transaction mode of its own, it relies on context saved from a previous SEE or CHG. The very first executable logic for all functions, both MAINT and BROWSE. AA100-CHECK-FUNCTION validates the function code. %PREINIT fires before VARIABLE-STORAGE is initialized, before TEST-KEY and TEST-FUNCT are set. No screen fields should be referenced here (except SFUNCT, SKEY, SCOMPL, SERRMSG) unless the mask is verified. Useful for DB binding (DL/1 PCB scheduling, SQL CONNECT), or to change D-LIMITER or WINDOW-COLOR. First, the program runs the pre-initialization step — paragraph A-A-100 CHECK FUNCTION — which includes the percent-PREINIT insertion point. This is where a developer can intercept execution at the very beginning, before any working storage is set up. Initialization for all MAINT-FUNCTIONs. VARIABLE-STORAGE is set to LOW-VALUES just before %INIT executes. Use %INIT to initialize custom work fields defined in %VARSTOR or %DATADEF, especially COMP-3 fields that need to be zeroed. Do not reference screen fields (other than the four standard MAGEC fields) since the proper mask may not yet be active. Next is the initialization block — B-A-100 INIT STORAGE — containing the percent-INIT insertion point, where variable storage is cleared and custom fields can be initialized. Executed at the very top of the MAINT mainline for every transaction (NEW or CONTINUATION mode). Default logic handles PF7/PF8 (backward/ forward browse → transfers to xxxNXT), PF4 (transfer to xxxLOC), PF1/ PF2/PF11 (help), PF16/PF17 (copy/paste), and cursor-movement detection for implicit CHG. Developer can intercept any PF key, alter SKEY/ TEST-KEY and SFUNCT/TEST-FUNCT, or bypass the entire mainline. Then the maintenance mainline begins — A-A-M-200 MAINTENANCE MAINLINE — which includes the percent-PFKEYM insertion point. This handles P-F keys and allows the developer to intercept or redirect processing at the top of the mainline. Executed only for MAINT functions. Initializes 3270 screen attributes (field protection, intensity, color). %INITATB fires at the very end of BA210-MAINT-SCREEN immediately before BA299-EXIT. Developer can override default attribute values based on function code, operator ID, or any other criteria. Do not reference file data items here — I/O has not yet been done. The attribute initialization step follows — B-A-210 MAINT SCREEN — with the percent-INITATB insertion point, where screen field attributes such as color and protection can be customized. KEY = LAST KEY ? The MMP tests whether the key value currently in SKEY equals the key that was saved from the prior SEE or CHG (TWA-LAST-KEY). If yes, a READ-NEXT is performed to advance sequentially. If no, the key has changed and a different path is followed. A decision: is the key on the screen equal to the last key from the previous transaction? If yes, we proceed to read the next record. If no, a different path is taken. PRIOR READ NOT OK ? Tests whether the prior read (from the previous SEE or CHG context) completed successfully. If NOT OK (e.g. end-of-file or error), the flow routes to BLNKSCR/SNDSCRN to blank the screen and send it. If OK, flow drops down to %REDNX to read the next record. Another decision: was the prior read successful? If not okay, the screen is blanked and sent back. If okay, we continue to read the next record. TEST-KEY = SPACES ? When KEY ≠ LAST KEY, the program tests if TEST-KEY is spaces. A spaces key is treated as INVALID KEY and routes to BLNKSCR. If not spaces, flow continues to %NORMKEY for key normalization. If the key changed, we check whether the test key is spaces. Spaces means an invalid key — the screen is blanked. Otherwise, we normalize the key. Normalizes the operator-entered key value in SKEY into the internal FILE-KEY format used by MAGECIO. Standard logic handles multi-component keys, mixed data representations (COMP, COMP-3, alphanumeric, etc.). %NORMKEY fires after standard normalization succeeds (no error). The developer can add further key edits, massage the key, or add prefix/ suffix based on terminal/operator/location. On error: GO TO BA480-BAD-KEY. FILE-KEY is then MOVE'd to NORMALIZED-KEY automatically. Note: this insertion point is for MAINT functions only; %NKLOC handles browse. The key normalization step — B-A-400 NORMALIZE MAINT KEY — with the percent-NORMKEY insertion point, converts the screen key into the internal file-key format. On an invalid key, processing branches right to blank the screen. Reads the next (or previous, if PF7) record pseudo-sequentially from the Primary Data Class. Direction is controlled by TWA-BROWSE-DIRECTION (F=forward, B=backward). Default logic calls MAGECIO with REDNX command, then PERFORMs JA100-LOGICAL-JOIN. %REDNX appears in BOTH the MAINT and BROWSE mainlines; if exiting with a GO TO, check which mainline you are in (MAINT → AAM440-TEST-RETURN-CODE; BROWSE → AAL440-TEST-RETURN-CODE). Do not code paragraph names inside %REDNX (they would be duplicated). Now the program reads the next record — A-A-M-430 READ NEXT RECORD — using the percent-REDNX insertion point, calling MAGEC-I-O to sequentially retrieve the next or previous record from the primary file. Executed after each standard READ of the Primary Data Class (both MAINT and BROWSE functions). Used to READ secondary files or compute "derived fields" to form the Logical Record. Automatic Logical Join generates code here automatically. Developer can add or modify READs of secondary files. TWA-DB-REQUEST is saved/restored by the MMP before PERFORMING JA100. To exit: GO TO JA900-RETURN (not JA999-EXIT). If referencing screen fields, test IF (MAINT-FUNCTION) or IF (BROWS-FUNCTION) first. After reading the record, the logical join step runs — J-A-100 LOGICAL JOIN — via the percent-JOIN insertion point. This reads secondary files and computes derived fields to build the full logical record. Executed in NEW-TRANSACTION-MODE of MAINT functions (only if REC-FOUND) to MOVE data from the Logical Record (TWA-DB-DATA) to the screen fields. %COMP is inserted at the end of BB200-FILL-SCREEN, after all generated MOVEs from database fields to screen, just before BB299-EXIT. Developer can move literals, computed values, or code translations. Can also alter 3270 attributes (e.g. color) based on data values. SERRMSG can be used for extra display capacity. Do not reference MSK652 (Browse Mask) here. For numeric screen fields use both S_____-N (numeric equiv.) and S_____-ED (edit pattern). The fill-screen step — B-B-200 FILL SCREEN — with the percent-COMP insertion point, moves database field values to the screen for display, after all the standard generated moves. Constructs the Master (Primary) key in operator-entry format (including slashes, etc.) from the record data and MOVEs the result to SKEY and TWA-LAST-KEY. This is performed from the NXT maintenance mainline to simulate the operator's full key entry for the cursor-selection and forward/backward reading features. The default code for %SKEYBLD IS the entire CA800-BUILD-SKEY routine (including paragraph names). Handles multi-component keys, mixed data representations. For minor changes, consider %SNDSCRN instead. Next, the key-build step — percent-SKEYBLD — reconstructs the screen key value from the record just read, placing it into S-KEY so the operator can see which record is being displayed. Executed on INVALID KEY and on NOT-FOUND conditions (and on NEW-TRANSACTION- MODE of xxxADD — not applicable to NXT). Blanks the screen by MOVEing underscores to all screen variables. %BLNKSCR fires at the very end of BB100-BLANK-SCREEN, after all generated MOVEs. Developer can set selected screen fields to values other than underscores, read a file based on the key value, or test for key-edit failures (IF SCOMPLE = E). This logic executes only for MAINT functions; MSK652 (Browse Mask) fields may not be referenced here. If no record is found, or the key is invalid, or the prior read failed, the blank-screen step runs — B-B-100 BLANK SCREEN — with the percent-BLNKSCR insertion point, which clears the screen with underscore placeholders. Executed just before the MMP exits to MAGECCP (which will send the screen and terminate the task, or execute a fetch to another function). %SNDSCRN fires for both MAINT and BROWSE functions. No default logic. Developer can put finishing touches on the screen (blank zero fields, set highlight/color based on value thresholds, massage SKEY from cursor-select). If referencing non-standard screen fields, test which mask is active first (THIS-PGMS-MSK vs. COMMON-LOC-MSK). To exit: GO TO AA900-GOBACK. Just before returning to the MAGEC control program, the send-screen step runs — A-A-800 SEND SCREEN — with the percent-SNDSCRN insertion point, giving the developer a final chance to adjust screen content. Absolutely the last logic point in the online process for all functions. %GOBACK fires here, for both MAINT and BROWSE functions. A good place for IMS PCB TERMINATE or other end-of-execution cleanup. Screen data may be referenced only after interrogating which mask is initialized. Finally, the program reaches A-A-900 GOBACK — with the percent-GOBACK insertion point — the absolute last opportunity to insert code before control returns to the MAGEC control program. This diagram describes the logic flow of the N-X-T function — referred to in code as "x-x-x-N-X-T" — in a MAGEC-generated online maintenance program, or M-M-P. The NXT function reads the next (or previous) record sequentially from the primary data class and displays it on the maintenance screen. An important note: the NXT function has NO new-transaction mode of its own. It relies on context stored in the Task Work Area from a prior SEE or CHG function. If NXT is invoked without that prior context, it will behave as if a SEE had just been done. Processing begins at the very top with the percent-PREINIT insertion point inside paragraph A-A-100 CHECK FUNCTION. This fires for every function and every mode. The developer can intercept execution here before any working storage is initialized. Next is percent-INIT inside B-A-100 INIT STORAGE, where variable storage is cleared to low-values and the developer can initialize custom work fields. The maintenance mainline then starts with percent-PFKEYM inside A-A-M-200 MAINTENANCE MAINLINE, which handles P-F key detection and allows early interception of the transaction. Attribute initialization follows — percent-INITATB in B-A-210 MAINT SCREEN — where 3270 screen field attributes such as color and protection level can be overridden. A decision is then made: is the key on the screen equal to the last key saved from the prior SEE or CHG? If yes, a second decision checks whether the prior read was successful. If the prior read was not okay, processing branches right to blank the screen. If okay, it proceeds directly to read the next record. If the key changed (not equal to last key), the program checks whether the test key is spaces. Spaces means invalid key, and the screen is blanked. Otherwise, the key is normalized by percent-NORMKEY in B-A-400 NORMALIZE MAINT KEY. On an invalid key format, processing again routes to blank the screen. On a valid key, or directly from a successful prior read, the program executes percent-REDNX in A-A-M-430 READ NEXT RECORD. This calls the MAGEC I-O module to read the next or previous record based on browse direction. If no record is found, processing routes to blank the screen. When a record is found, the percent-JOIN insertion point in J-A-100 LOGICAL JOIN runs to read secondary files and compute derived fields, assembling the complete logical record. Again, a not-found here routes to blank the screen. With the logical record assembled, percent-COMP in B-B-200 FILL SCREEN moves database field values to screen display fields. Then percent-SKEYBLD rebuilds the screen key in S-KEY from the record data, so the operator can see the key of the record now displayed. On both the found and not-found paths, processing converges at A-A-800 SEND SCREEN, which contains the percent-SNDSCRN insertion point — the developer's last chance to fine-tune the screen before it is sent. Finally, A-A-900 GOBACK with percent-GOBACK is the absolute last point in the flow, after which control returns to the MAGEC control program.