Important Notice

The pages on this site contain documentation for very old MS-DOS software, purely for historical purposes. If you're looking for up-to-date documentation, particularly for programming, you should not rely on the information found here, as it will be woefully out of date.

■ DEF FN function definitions are not permitted inside control
  constructs such as IF...END IF, SELECT...CASE, and so on.
 
■ Possible solution:
 
  • Move the DEF FN definition outside the control structure.
 
■ If you need additional help, move the cursor to a keyword
  and press F1 to open the Help window.