This command creates the output FDL file, stores the current FDL
 definition into it, and terminates the EDIT/FDL session.  ^Z
 (control/Z) entered at the main function menu is equivalent to the
 EXIT command.

 If the current definition is empty when the exit function is used, no
 FDL file is output.  Refer to the help on "Operation Files" for more
 information on EDIT/FDL's treatment of input and output files.