NXT Function — Next Record logic flow diagram. 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. Reads the next (or previous) record sequentially from the primary data class and displays it on the maintenance screen. Two decision branches handle key-changed and prior-read-failed conditions; all error paths converge at BB100-BLANK-SCREEN before SEND-SCREEN. Entry into the NXT Function (SFUNCT = xxxNXT). 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). Click on any node on this chart for a pop-up with a fuller explanation plus a link to the documentation page for the insertion point referred to. insert_main.htm#topMAIN The very first executable logic for all functions. 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. AA100-CHECK-FUNCTION insert_main.htm#insert001029 MAIN Narrative for function. https://www.magec.com/DOC/genmmp_main.htm#genmmp002011 MAIN 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. BA100-INIT-STORAGE insert_main.htm#insert001016 MAIN Mainline logic for all maintenance functions. https://www.magec.com/DOC/genmmp_main.htm#genmmp004057 MAIN Executed at the very top of the MAINT mainline for every transaction. 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. insert_main.htm#insert001028 MAIN AAM200-MAINTENANCE-MAINLINE First 10-bytes of Mask Area give Mask ID, Cursor position, Entry key detection (ENTER, CLEAR, PF1, PA1, etc.). TWA-MSK-AREA https://www.magec.com/DOC/genmmp_main.htm#genmmp004025 MAIN 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. BA210-MAINT-SCREEN insert_main.htm#insert001017 MAIN list of 3270 attributes and their meanings. 3270 Attributes https://www.magec.com/DOC/magref_main.htm#MAGREF001001 MAIN 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, the key has not changed — proceed to test whether the prior read was successful. If NO, the key changed — test whether it is spaces. Tests whether the prior read (from the previous SEE or CHG context) completed successfully. If NOT OK (end-of-file or error), flow routes right to BLNKSCR to blank the screen. If OK, flow drops down to %REDNX to read the next record. Tests whether the prior read (from the previous SEE- or CHG context) completed successfully. If NOT OK (end-of-file or error), flow routes right to BLNKSCR to blank the screen. If OK, flow drops down to %REDNX to read the next record. Tests whether the prior read (from the previous SEE or CHG context) completed successfully. If NOT OK (end-of-file or error), flow routes right to BLNKSCR to blank the screen. If OK, flow drops down to %REDNX to read the next record. When KEY ≠ LAST KEY, the program tests if TEST-KEY is spaces. A spaces key is treated as INVALID KEY and routes right to BLNKSCR. If not spaces, flow continues down to %NORMKEY for key normalization. This is done to try to satisfy the need for a SEE (or other) Function to act as the NEW-TRANSACTION for this task. Normalizes the operator-entered key value in SKEY into the internal FILE-KEY format used by MAGECIO. %NORMKEY fires after standard normalization succeeds. 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. Note: this insertion point is for MAINT functions only; %NKLOC handles browse. insert_main.htm#insert001026 MAIN BA400-NORMALIZE-MAINT-KEY Normalizes the operator-entered key value in SKEY into the internal FILE-KEY format used by MAGECIO. %NORMKEY fires after standard normalization succeeds. 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. Note: this insertion point is for MAINT functions only; %NKLOC handles browse. BA400-NORMALIZE-MAINT-KEY insert_main.htm#insert001026 MAIN 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). %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. AAM430-READ-NEXT-REC insert_main.htm#insert001033 MAIN Reads secondary files and computes derived fields to assemble the complete logical record. 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. NOT FOUND here routes to BLNKSCR. JA100-LOGICAL-JOIN insert_main.htm#insert001018 MAIN Moves database field values from the Logical Record (TWA-DB-DATA) to screen fields. %COMP fires at the end of BB200-FILL-SCREEN, after all generated MOVEs, just before BB299-EXIT. Developer can move literals, computed values, or code translations, and can alter 3270 attributes based on data values. Do not reference MSK652 (Browse Mask) here. BB200-FILL-SCREEN insert_main.htm#insert001005 MAIN 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 cursor-selection and forward/backward reading. The default code for %SKEYBLD IS the entire CA800-BUILD-SKEY routine. BB200-FILL-SCREEN insert_main.htm#insert001038 MAIN Executed on INVALID KEY and on NOT-FOUND conditions. 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. BB100-BLANK-SCREEN insert_main.htm#insert001003 MAIN MOVEing 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. BB100-BLANK-SCREEN insert_main.htm#insert001003 MAIN MOVEing 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. BB100-BLANK-SCREEN insert_main.htm#insert001003 MAIN Executed on INVALID KEY and on NOT-FOUND conditions. 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. BB100-BLANK-SCREEN insert_main.htm#insert001003 MAIN Executed on INVALID KEY and on NOT-FOUND conditions. 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. BB100-BLANK-SCREEN insert_main.htm#insert001003 MAIN Executed just before the MMP exits to MAGECCP. %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. To exit: GO TO AA900-GOBACK. AA800-SEND-SCREEN insert_main.htm#insert001039 MAIN 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. AA900-GOBACK insert_main.htm#insert001012 MAIN NXT Function processing complete. NXT Function processing complete.