Another Reason to Use P-Fields

January 26, 2005 Hey, Ted:

Within a subfile, I am using an indicator to highlight a field if the value of that field is invalid. Is there a way, when I read a subfile record, to analyze the attributes of the field to see if the indicator was switched on or off when the subfile record was written? My problem is that the display attribute is losing its original setting.

–Alan

I don’t know of a way to determine the original setting. I have included hidden one-byte fields in a subfile to store the settings of indicators so I could reset the indicators before updating the subfile record. You have put your finger on a good reason to use p-fields instead of indicators to control display file attributes.

Here’s a display file, SFL223D, which uses indicator 71 to display a negative balance amount in reverse image.

 A                                      DSPSIZ(24 80 *DS3)
 A          R SFL01                     SFL
 A            LINENBR01      3  0O  9  2EDTCDE(4)
 A            NAME01        20   O    +2
 A            BALANCE01      9  2O    +2EDTCDE(J)
 A  71                                  DSPATR(RI)
 A          R CTL01                     SFLCTL(SFL01)
 A                                      CA03(03)
 A                                      SFLDSP
 A                                      SFLDSPCTL
 A                                      SFLSIZ(11)
 A                                      SFLPAG(10)

Here’s a short program, SFL223R, which loads some records into the subfile and updates one of them. The first time the subfile is displayed, Don’s and Lou’s records show a balance in reverse image. When Don’s name is changed to Bubba, the reverse image attribute disappears.

 H dftactgrp(*no) actgrp(*caller)
 H option(*srcstmt: *nodebugio)

 Fsfl223d   cf   e             workstn
 F                                     sfile(sfl01:rrn)

 D rrn             s              3  0

 D Load            pr
 D  Name                         20    value
 D  Balance                       9p 2 value
 D  RecNbr                        3p 0

 D ChangeName      pr
 D  RecNbr                        3p 0 value
 D  NewName                      20    value

  /free
      Load('Bob': 200: RRN);
      Load('Don': -35: RRN);
      Load('Jim': 25.95: RRN);
      Load('Lew': 180: RRN);
      Load('Lou': -99999: RRN);
      Load('Sue': 500: RRN);
      Load('Tom': 1750: RRN);
      exfmt ctl01;
      ChangeName(2: 'Bubba');
      exfmt ctl01;
      *inlr = *on;
  /end-free

 P Load            b
 D                 pi
 D  Name                         20    value
 D  Balance                       9p 2 value
 D  RecNbr                        3p 0
  /free
    RecNbr += 1;
    LineNbr01 = RecNbr;
    Name01 = Name;
    Balance01 = Balance;
    *in71 = (Balance01 < *zero);
    write sfl01;
  /end-free
 P                 e

 P ChangeName      b
 D                 pi
 D  RecNbr                        3p 0 value
 D  NewName                      20    value
  /free
    chain RecNbr sfl01;
    if %found();
       Name01 = NewName;
       update sfl01;
    endif;
  /end-free
 P                 e

Here’s the same display file, but the setting of the balance field is now controlled by p-field BALATTR01, which is written to the subfile record. The display attributes of the balance field are no longer dependent on the setting of an indicator.

 A                                      DSPSIZ(24 80 *DS3)
 A          R SFL01                     SFL
 A            LINENBR01      3  0O  9  2EDTCDE(4)
 A            NAME01        20   O    +2
 A            BALANCE01      9  2O    +2EDTCDE(J)
 A                                      DSPATR(&BALATTR01)
 A            BALATTR01      1A  P
 A          R CTL01                     SFLCTL(SFL01)
 A                                      CA03(03)
 A                                      SFLDSP
 A                                      SFLDSPCTL
 A                                      SFLSIZ(11)
 A                                      SFLPAG(10)

Here’s the revised RPG code. When Don’s name is changed to Bubba, the balance of -35 continues to be displayed in reverse image.

 H dftactgrp(*no) actgrp(*caller)
 H option(*srcstmt: *nodebugio)

 Fsfl224d   cf   e             workstn
 F                                     sfile(sfl01:rrn)

 D rrn             s              3  0
 D Normal          c                   x'20'
 D Reverse         c                   x'21'

 D Load            pr
 D  Name                         20    value
 D  Balance                       9p 2 value
 D  RecNbr                        3p 0
 D ChangeName      pr
 D  RecNbr                        3p 0 value
 D  NewName                      20    value

  /free
      Load('Bob': 200: RRN);
      Load('Don': -35: RRN);
      Load('Jim': 25.95: RRN);
      Load('Lew': 180: RRN);
      Load('Lou': -99999: RRN);
      Load('Sue': 500: RRN);
      Load('Tom': 1750: RRN);
      exfmt ctl01;
      ChangeName(2: 'Bubba');
      exfmt ctl01;
      *inlr = *on;
  /end-free

 P Load            b
 D                 pi
 D  Name                         20    value
 D  Balance                       9p 2 value
 D  RecNbr                        3p 0
  /free
    RecNbr += 1;
    LineNbr01 = RecNbr;
    Name01 = Name;
    Balance01 = Balance;
    if (Balance01 >= *zero);
       BalAttr01 = Normal;
    else;
       BalAttr01 = Reverse;
    endif;
    write sfl01;
  /end-free
 P                 e

 P ChangeName      b
 D                 pi
 D  RecNbr                        3p 0 value
 D  NewName                      20    value
  /free
    chain RecNbr sfl01;
    if %found();
       Name01 = NewName;
       update sfl01;
    endif;
  /end-free
 P                 e

To learn more about p-fields, see the article “Anatomy of a P-Field.”

–Ted

Click here to contact Ted Holt by e-mail.

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