The programming function CNTL2TXT copies the values of XLAST and YLAST to the text-handling coordinates XLSTT and YLSTT. Assigning missing values to X and Y forces the LABEL function to use the values of XLSTT and YLSTT to position the star. The text string V is the character code for the star figure in the MARKER font assigned by the STYLE variable. 
   function='cntl2txt'; output;
   function 'label'; style='marker'; text='V';
      angle=0; color='white'; size=10; x=.; y=.;
      output;
   end;
run;