void u8_line_clear (struct u8_line *);
char *u8_line_reserve (struct u8_line *, int x0, int x1, int n);
void u8_line_put (struct u8_line *, int x0, int x1, const char *s, int n);
void u8_line_clear (struct u8_line *);
char *u8_line_reserve (struct u8_line *, int x0, int x1, int n);
void u8_line_put (struct u8_line *, int x0, int x1, const char *s, int n);