refresh(3NCURSES)														 refresh(3NCURSES)

NAME

       doupdate, redrawwin, refresh, wnoutrefresh, wredrawln, wrefresh - refresh curses windows and lines

SYNOPSIS

       #include <curses.h>

       int refresh(void);
       int wrefresh(WINDOW *win);
       int wnoutrefresh(WINDOW *win);
       int doupdate(void);
       int redrawwin(WINDOW *win);
       int wredrawln(WINDOW *win, int beg_line, int num_lines);

DESCRIPTION

       The  refresh  and  wrefresh  routines (or wnoutrefresh and doupdate) must be called to get actual output to the terminal, as other routines
       merely manipulate data structures.  The routine wrefresh copies the named window to the physical terminal screen, taking into account  what
       is  already  there  to do optimizations.  The refresh routine is the same, using stdscr as the default window.  Unless leaveok has been en-
       abled, the physical cursor of the terminal is left at the location of the cursor for that window.

       The wnoutrefresh and doupdate routines allow multiple updates with more efficiency than wrefresh alone.	In  addition  to  all  the  window
       structures,  curses  keeps  two	data  structures  representing	the terminal screen: a physical screen, describing what is actually on the
       screen, and a virtual screen, describing what the programmer wants to have on the screen.

       The routine wrefresh works by first calling wnoutrefresh, which copies the named window to the virtual screen, and then	calling  doupdate,
       which compares the virtual screen to the physical screen and does the actual update.  If the programmer wishes to output several windows at
       once, a series of calls to wrefresh results in alternating calls to wnoutrefresh and doupdate, causing several  bursts  of  output  to  the
       screen.	 By  first calling wnoutrefresh for each window, it is then possible to call doupdate once, resulting in only one burst of output,
       with fewer total characters transmitted and less CPU time used.	If the win argument to wrefresh is the global variable curscr, the  screen
       is immediately cleared and repainted from scratch.

       The  phrase  "copies the named window to the virtual screen" above is ambiguous.  What actually happens is that all touched (changed) lines
       in the window are copied to the virtual screen.	This affects programs that use overlapping windows; it means that if two windows  overlap,
       you  can  refresh them in either order and the overlap region will be modified only when it is explicitly changed.  (But see the section on
       PORTABILITY below for a warning about exploiting this behavior.)

       The wredrawln routine indicates to curses that some screen lines are corrupted and should be thrown away before anything  is  written  over
       them.  It touches the indicated lines (marking them changed).  The routine redrawwin() touches the entire window.

RETURN VALUE

       Routines  that  return  an  integer return ERR upon failure, and OK (SVr4 only specifies "an integer value other than ERR") upon successful
       completion.

       X/Open does not define any error conditions.  In this implementation

	      wnoutrefresh
		   returns an error if the window pointer is null, or if the window is really a pad.

	      wredrawln
		   returns an error if the associated call to touchln returns an error.

NOTES

       Note that refresh and redrawwin may be macros.

PORTABILITY

       The XSI Curses standard, Issue 4 describes these functions.

       Whether wnoutrefresh() copies to the virtual screen the entire contents of a window or just its changed portions has never been	well-docu-
       mented  in  historic  curses  versions  (including  SVr4).  It might be unwise to rely on either behavior in programs that might have to be
       linked with other curses implementations.  Instead, you can do an explicit touchwin() before the wnoutrefresh() call to	guarantee  an  en-
       tire-contents copy anywhere.

SEE ALSO

       ncurses(3NCURSES), outopts(3NCURSES) curses_variables(3NCURSES).

																 refresh(3NCURSES)