The result is an integer vector of the file tie number of all tied files.  If no files are tied, the result is empty.  The elements of the result are in the order in which the files were tied.

Examples

      '/home/pete/SALESFILE' ⎕FSTIE 16

      '../budget/COSTFILE' ⎕FSTIE 2

      'PROFIT' ⎕FCREATE 5

      ⎕FNUMS
16 2 5

      ⎕FNUMS,⎕FNAMES
16 /home/pete/SALESFILE
 2 ../budget/COSTFILE
 5 PROFIT

      ⎕FUNTIE ⎕FNUMS
      ⍴⎕FNUMS
0