curs_scroll 3x 2024-05-25 ncurses 6.5 Library calls

curs_scroll(3x)                  Library calls                 curs_scroll(3x)


       scroll, scrl, wscrl - scroll a curses window


       #include <curses.h>

       int scroll(WINDOW * win);

       int scrl(int n);
       int wscrl(WINDOW * win, int n);


       scroll  scrolls  the  given window up one line.  That is, every visible
       line we might number i becomes line i-1.  The text of the top  line  in
       the  window  disappears  and  the  bottom  line is populated with blank
       characters; see bkgd(3x) or bkgrnd(3x).  As  an  optimization,  if  the
       scrolling  region  of  the  window  is  the entire screen, the physical
       screen may be scrolled at the same time; see curscr(3x).

       scrl and wscrl scroll  stdscr  or  the  specified  window  up  or  down
       depending on the sign of n.

       o   For positive n, line i+n becomes i (scrolling up);

       o   for negative n, line i-n becomes i (scrolling down).

       The  cursor does not move.  These functions perform no operation unless
       scrolling is enabled for the window via scrollok(3x).


       These functions return ERR upon failure and OK upon success.

       ncurses returns ERR if scrolling is not  enabled  in  the  window,  for
       example with scrollok(3x), or if the WINDOW pointer is null.


       scrl and wscrl may be implemented as macros.

       Unusually,  there  is  no wscroll function; scroll behaves as one would
       expect wscroll to, accepting a WINDOW pointer argument.


       X/Open Curses, Issue 4 describes these functions.  It defines no  error

       SVr4  specifies  only "an integer value other than ERR" as a successful
       return value.

       SVr4  indicates  that  the   optimization   of   physically   scrolling
       immediately  if  the scroll region is the entire screen "is" performed,
       not "may be" performed.  ncurses deliberately does not  guarantee  that
       this  will occur, to leave open the possibility of smarter optimization
       of multiple scroll actions on the next update.

       Neither SVr4 curses nor  X/Open  Curses  specify  whether  the  current
       attribute  or  current  color  pair  of  blanks generated by the scroll
       function are zeroed.  ncurses does so.


       curses(3x), curs_outopts(3x)

ncurses 6.5                       2024-05-25                   curs_scroll(3x)