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RedHat 9 (Linux i386) - man page for wnoutrefresh (redhat section 3X)

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curs_refresh(3X)								 curs_refresh(3X)

       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  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 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  struc-
       tures  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

       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  wnoutre-
       fresh  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 actu-
       ally 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 completion.

       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)

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