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man refresh(3)
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curs_refresh(3)                                                curs_refresh(3)


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


       #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);


       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 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 enabled, 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

       o   a physical screen, describing what is actually on the screen, and

       o   a virtual screen, describing what the programmer wants to have on the

       The routine wrefresh works by

       o   first calling wnoutrefresh, which copies the named window to the
           virtual screen, and

       o   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 physical screen (i.e., the global
       variable curscr), the screen is immediately cleared and repainted from

       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.


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

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

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

               returns an error if the associated call to touchln returns an


       Note that refresh and redrawwin may be macros.


       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-documented 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 entire-contents copy anywhere.


       curses(3X), curs_outopts(3X) curs_variables(3X).


ncurses 6.4 - Generated Tue Jan 3 13:39:07 CST 2023
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