int ss_get_char (struct substring *);
size_t ss_get_chars (struct substring *, size_t cnt, struct substring *);
bool ss_get_until (struct substring *, char delimiter, struct substring *);
int ss_get_char (struct substring *);
size_t ss_get_chars (struct substring *, size_t cnt, struct substring *);
bool ss_get_until (struct substring *, char delimiter, struct substring *);