string_to_flags
int string_to_flags(char **, unsigned long *, unsigned long *);
int string_to_flags(char **, unsigned long *, unsigned long *);
if (string_to_flags(&flags, &set, &clear))
(string_to_flags(&flags, &flagset, NULL) != 0))
if (string_to_flags(&fflags, &fileflags, NULL))
else if (string_to_flags(&val, &ip->st_flags, NULL)