Fields with No Underlying Data Variable

Designer: You can set the field option OMITFROMSTRUCT in the Designer, to omit the field from the form data structure. When the form is read from the library, that field will have NULLP as its underlying data variable. You can then resolve the data pointer by calling sf_datap() for that field, or you can leave the data pointer as a NULLP. See the Designer User's Guide for information on the OMITFROMSTRUCT field option.

Code: You can specify NULLP as the underlying data variable for a data field or a memo field.

General: The processing of a field that is not associated with an underlying data variable is described below:

• nThe form processing system initially displays the field as empty except for any protected characters in the field picture. To display a value in the field, you must call fld_upd().
  
  
• nThe user may type a value in the field (if the field is not SKIP or PROTECTED).
  
  
• nIf a value is typed in the field, the value is validated when the user leaves the field.
  
  
• nThe value is not converted and stored. To get the converted value from the field, you must use fld_get().
  
  
• nIf you update the form during processing (with a call to fm_upd() or fm_updflds()), any value currently displayed in the field is cleared.

Caution: Underlying data variables of NULLP are not supported for fields in a scrollable region.