netcdf ref_nulls {
dimensions:
	_scalar_ = 1 ;
variables:
	int test(_scalar_) ;
		test:nul_sng = 0 ;
		test:empty_sng = "" ;
		test:space_sng = " " ;
		test:zero_sng = 0 ;
		test:nul0 = 0 ;
data:

 test = 1 ;
}