wscrl – scroll a curses window
int scroll(WINDOW *win);
int scrl(int n);
int wscrl(WINDOW *win, int n);
The scroll routine scrolls the window up one line.
This involves moving
the lines in the window data structure.
As an optimization, if the scrolling
region of the window is the entire screen, the physical screen may be scrolled
at the same time.
For positive n, the scrl and wscrl routines scroll the
window up n lines (line i+n becomes i); otherwise
scroll the window down n lines.
This involves moving the lines in the
window character image structure.
The current cursor position is not changed.
These routines return ERR upon failure, and OK (SVr4 only specifies
"an integer value other than ERR") upon successful completion.
X/Open defines no error conditions.
Note that scrl and scroll may be macros.
The SVr4 documentation says that the optimization of physically scrolling
immediately if the scroll region is the entire screen "is" performed, not
"may be" performed.
This implementation deliberately does not guarantee
that this will occur, to leave open the possibility of smarter
optimization of multiple scroll actions on the next update.