Insert Slack Byte Items Menu Item

The plug-in ensures correct placement of SYNC items. It also provides a feature that generates new data items to occupy the slack bytes between SYNC items.

The Insert slack byte items menu item is available on the Copybook Schema resource:

Insert Slack Byte Items button

For an example of how this menu item modifies the copybook body, consider this copybook as displayed before the Insert slack byte items menu item is used: 

01 TOP-LEVEL1.
    02 TEXT PIC X.
    02 COMP-ITEM PIC S9(10) COMP SYNC

The SYNC clause in the COMP-ITEM item adds three slack bytes in front the item. However, you have no access to those bytes. If you would like to be able to manipulate their values as well as the values of TEXT and COMP-ITEM, click the Insert slack byte item menu item.

Your copybook then becomes: 

01 TOP-LEVEL1.
02 TEXT PIC X.
*** Slack bytes before COMP-ITEM
    02 SLACK-BYTES0 PIC X(3).
***
    02 COMP-ITEM PIC S9(10) COMP SYNC.

The new layout is fully compatible with the original copybook. The TEXT and COMP-ITEM lines are still located at the same offsets, but you now have access to the slack bytes that were previously inaccessible. However, if you modify PICTURE or USAGE clauses of SLACK-BYTES0, that might change the placement of COMP-ITEM.

Warning: This feature does not add definitions between top-level items. Doing so would render the layout incompatible because the new items would be positioned at the 8-byte boundary.

If needed, you can access those slack bytes by adding another top-level item with the REDEFINE clause and a larger size.