function [FillVal]=ncgetFillVal(ncid,varname);
% [FillVal]=ncgetFillVal(ncid,varname)
%           return the missing_value or _FillValue of varname

global useNativeMatlabNetcdf; 
if isempty(useNativeMatlabNetcdf); useNativeMatlabNetcdf = ~isempty(which('netcdf.open')); end;

FillVal=[];
if useNativeMatlabNetcdf;
    varid = netcdf.inqVarID(ncid,varname);
    [atts]=ncatts(ncid,varid);
    if any(ismember(atts,'missing_value'))
        FillVal = double(netcdf.getAtt(ncid,varid,'missing_value'));
    elseif any(ismember(atts,'_FillValue'))
        FillVal = double(netcdf.getAtt(ncid,varid,'_FillValue'));
    end;
else
    FillVal = ncid{varname}.missing_value(:);
    if isempty(FillVal);
        FillVal = ncid{varname}.FillValue_(:);
    end
end