undef("getfilevaratt_value")
function getfilevaratt_value(f[1]:file, varname[1]:string, attname[1]:string)
local varAtts, iAtt, attValue
begin
  if (isfilevar(f,varname)) then 
      varAtts = getfilevaratts(f, varname)
      iAtt    = ind(varAtts.eq.attname)
      if (ismissing(iAtt)) then
          print("getfilevaratt_value: FATAL: variable "+varname+" does not have an attribute named "+attname)
          exit
      end if
      attValue = f->$varname$@$attname$
      return(attValue)
  else
      print("getfilevaratt_value: FATAL: variable "+varname+" is not in the file")
      exit
  end if
end