Uncommon Knowledge - WC_Reset%

WC_Reset% is a flag variable used to tell the window interpreter that the developer has made changes to other common variables and that these changes ought to be evaluated and processed. It may take a value of 1 to 6, these being defined in the WINDOW.CONSTANTS record in the INCLUDE file as follows

       EQU CLEAN.UP.LINE$           TO 1
       EQU CLEAN.UP.EDIT$           TO 2
       EQU RESET.EDIT$          TO 3
       EQU RESET.PROMPT$        TO 4
       EQU RESET.RECORD$        TO 5
       EQU RESET.WINDOW$        TO 6

These values are actually quite self- explanatory once you know what they do! WC_Reset% is only looked at at certain predefined points when the window is running, and some processes ignore it entirely. Actions caused by WC_Reset% can be misleading. To illustrate, WC_Reset% might be set to 6 on a default process and the window might close. It might therefore be assumed that the default process was responsible for the closing of the window. This is only partially true. Heavy use of commuter logic reveals that the default logic ignores the setting of WC_Reset% and that it is the subsequent Pre Prompt logic that picks up the request to close the window.

In the following discussion consideration will be given to how various values of WC_Reset% alter the window logic flow. Other variables affected by WC_Reset% will be considered by example as they are encountered. When the text states that "the perpetual process is run" (or some other process) it is implicit that this only happens if a perpetual process (or the appropriate process) has been defined. In all cases a WC_Reset% value of 6 closes the window so this will not be repeated to save space.

Catalyst Calls and Commands may be executed before a window is invoked by adding the construct(s) PREAPP=@Code Command@ to the command line. If WC_Reset% is set here, it will be ignored until additional window processing has occurred. Thus if WC_Reset% were set to 6 here, the window would still display and execute various processes before actually closing. If a PREAPP wishes to close the window, it should set WC_WDone% to 1 and the window will close immediately. Note that accessing WINDOW_COMMON at this stage of the window interpreter requires careful manipulation of the COMMON block. At this stage, although WC_Reset% and WC_WDone% can be accessed, the various dimensioned common variables cannot. Therefore a special common block must be constructed (called for example WINDOW_COMMON_SHORT%) which contains all of the common variables up to (but not including) the first dimensioned common variable (WC_W%( WC_W_CNT%)). This can then be $INSERTed and the variables may then be referenced without fatal error messages regarding unassigned common variables.

As with Pre-App, Pre-Init ignores the WC_Reset% variable. If it is required that the window be exited, use the WC_WDone% variable and WINDOW_COMMON_SHORT%.

As with Pre-App, Post-Init ignores the WC_Reset% variable. If it is required that the window be exited, use the WC_WDone% variable and WINDOW_COMMON_SHORT%.

The Pre Prompt Process looks at WC_Reset% values of 4, 5 and 6.

Ignores WC_Reset%.

The Edit process looks at all WC_Reset% values except in the case of multivalued fields (both associated and non-associated) where WC_Reset% is ignored. (NB please remember the caveat that in this article we are only considering effect on window flow).

The Post Prompt Process looks at WC_Reset% values of 4, 5 and 6.

Ignores WC_Reset%

The Perpetual Process only looks at a WC_Reset% value of 6, which closes the window.

The Pre Read Process looks at WC_Reset% values of 5 and 6.

The Replace Read Process only looks at a WC_Reset% value of 6, which closes the window.

The Post Read Process only looks at a WC_Reset% value of 6, which closes the window.

The Pre Save Process looks at WC_Reset% values of 5 and 6.

The Rep Save Process looks at WC_Reset% values of 5 and 6.

The Post Save Process only looks at a WC_Reset% value of 6, which closes the window.

The Pre Delete Process looks at WC_Reset% values of 5 and 6.

The Rep Delete Process looks at WC_Reset% values of 5 and 6.

The Post Delete Process only looks at a WC_Reset% value of 6, which closes the window.

Ignores all values of WC_Reset%.

As with Pre-App, Post-Init ignores the WC_Reset% variable. If it is required that the window be exited, use the WC_WDone% variable and WINDOW_COMMON_SHORT%.

The Collector Save Process Process looks at WC_Reset% values of 5 and 6.

(Volume 2, Issue 8, Pages 8-11)