oracular (3) scroll.3ncurses.gz

NAME

       scroll, scrl, wscrl - scroll a curses window

SYNOPSIS

       #include <curses.h>

       int scroll(WINDOW *win);

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

DESCRIPTION

       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(3NCURSES) or bkgrnd(3NCURSES).  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(3NCURSES).

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

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

       •   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(3NCURSES).

RETURN VALUE

       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(3NCURSES), or if
       the WINDOW pointer is null.

NOTES

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

       scrl and scroll may be implemented as macros.

PORTABILITY

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

       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.

SEE ALSO

       ncurses(3NCURSES), outopts(3NCURSES)