salloc scalar scan section image short single quote smark space white stack memory standard parameter statement [1] [2] [3] assignment compound Fortran function label null stream I/O string [1] [2] [3] string constant string substitution string character [1] [2] comparison pack structure [1] [2] [3] [4] stsdas table switch symbolic constant [1] [2] [3] [4] [5] [6] syntax