insdelln, winsdelln — delete or insert lines into a window
int insdelln(int n);
int winsdelln(WINDOW *win, int n);
functions perform the following actions:
If n is positive, these functions insert n lines into the current
or specified window before the current line. The n last lines are
no longer displayed.
If n is negative, these functions delete n lines from the current
or specified window starting with the current line, and move the remaining
lines toward the cursor. The last n lines are cleared.
The current cursor position remains the same.
Upon successful completion, these functions return OK.
Otherwise, they return ERR.
No errors are defined.
First released in X/Open Curses, Issue 4.