_getsdn
length_sdn = _getsdn(optarg, &optarg, 0);
width_sdn = _getsdn(optarg, &optarg, 0);
cpi_sdn = _getsdn(optarg, &optarg, 1);
lpi_sdn = _getsdn(optarg, &optarg, 0);
#define getsdn(S) _getsdn(S, (char **)0, 0)
#define getcpi(S) _getsdn(S, (char **)0, 1)
SCALED _getsdn(char *, char **, int);