netcdf ref_tst_econst {
types:
  byte enum e1 {pass = 0, fail = 1, undefined = 2} ;
  byte enum e2 {defined = 0, undefined = 1} ;
variables:
	e1 test1 ;
	e2 test2 ;
	e1 test3 ;
data:

 test1 = pass ;

 test2 = undefined;

 test3 = fail;
}