I have created a RPG Subfile program for F4/Prompting. It also doubles as the validation program for data entered into the same field. Here's how it works:
Call the Subfile program with *Blanks when F4 is pressed and execute the Subfile for selection, otherwise bypass the Subfile by using USROPN on the WORKSTN file to be opened only on validation; meaning the parameter passed has data to be validated. Validate the data and pass back whatever is needed, even the whole record if need be. This Subfile/Validation program can be used in Interactive or Batch programs.
This will allow the program needing validation of data, and returned values(Description, etc) to not even have the file described in the "F" specs. This will allow for smaller programs and less number of places the file is used in the system.