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  * @Id: curs_refresh.3x,v 1.12 2005/05/15 16:18:49 tom Exp @
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<H1>curs_refresh 3x</H1>
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<PRE>
<!-- Manpage converted by man2html 3.0.1 -->
<STRONG><A HREF="curs_refresh.3x.html">curs_refresh(3x)</A></STRONG>                                       <STRONG><A HREF="curs_refresh.3x.html">curs_refresh(3x)</A></STRONG>


</PRE>
<H2>NAME</H2><PRE>
       <STRONG>doupdate</STRONG>, <STRONG>redrawwin</STRONG>, <STRONG>refresh</STRONG>, <STRONG>wnoutrefresh</STRONG>, <STRONG>wredrawln</STRONG>,
       <STRONG>wrefresh</STRONG> - refresh <STRONG>curses</STRONG> windows and lines


</PRE>
<H2>SYNOPSIS</H2><PRE>
       <STRONG>#include</STRONG> <STRONG>&lt;curses.h&gt;</STRONG>

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


</PRE>
<H2>DESCRIPTION</H2><PRE>
       The <STRONG>refresh</STRONG> and <STRONG>wrefresh</STRONG>  routines  (or  <STRONG>wnoutrefresh</STRONG>  and
       <STRONG>doupdate</STRONG>)  must be called to get actual output to the ter-
       minal, as other routines  merely  manipulate  data  struc-
       tures.   The  routine  <STRONG>wrefresh</STRONG> copies the named window to
       the physical terminal screen, taking into account what  is
       already there to do optimizations.  The <STRONG>refresh</STRONG> routine is
       the same, using <STRONG>stdscr</STRONG>  as  the  default  window.   Unless
       <STRONG>leaveok</STRONG>  has been enabled, the physical cursor of the ter-
       minal is left at the location of the cursor for that  win-
       dow.

       The  <STRONG>wnoutrefresh</STRONG> and <STRONG>doupdate</STRONG> routines allow multiple up-
       dates with more efficiency than <STRONG>wrefresh</STRONG> alone.  In  addi-
       tion  to  all the window structures, <STRONG>curses</STRONG> 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 <STRONG>wrefresh</STRONG> works by first calling <STRONG>wnoutrefresh</STRONG>,
       which copies the named window to the virtual  screen,  and
       then  calling  <STRONG>doupdate</STRONG>, 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 se-
       ries of calls to <STRONG>wrefresh</STRONG> results in alternating calls  to
       <STRONG>wnoutrefresh</STRONG>  and <STRONG>doupdate</STRONG>, causing several bursts of out-
       put to the screen.  By first calling <STRONG>wnoutrefresh</STRONG> for each
       window, it is then possible to call <STRONG>doupdate</STRONG> once, result-
       ing in only one burst of output, with fewer total  charac-
       ters transmitted and less CPU time used.  If the <EM>win</EM> argu-
       ment to <STRONG>wrefresh</STRONG> is the global variable <STRONG>curscr</STRONG>, 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
       <EM>touched</EM>  (changed)  lines  in the window are copied to the
       virtual screen.  This affects programs that  use  overlap-
       ping  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 <STRONG>PORTABILITY</STRONG> below for a  warning  about
       exploiting this behavior.)

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


</PRE>
<H2>RETURN VALUE</H2><PRE>
       Routines  that  return an integer return <STRONG>ERR</STRONG> upon failure,
       and <STRONG>OK</STRONG> (SVr4 only specifies "an integer value  other  than
       <STRONG>ERR</STRONG>") upon successful completion.

       X/Open  does not define any error conditions.  In this im-
       plementation

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

              <STRONG>wredrawln</STRONG>
                   returns  an  error  if  the associated call to
                   <STRONG>touchln</STRONG> returns an error.


</PRE>
<H2>NOTES</H2><PRE>
       Note that <STRONG>refresh</STRONG> and <STRONG>redrawwin</STRONG> may be macros.


</PRE>
<H2>PORTABILITY</H2><PRE>
       The XSI Curses standard, Issue  4  describes  these  func-
       tions.

       Whether  <STRONG>wnoutrefresh()</STRONG>  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  ex-
       plicit  <STRONG>touchwin()</STRONG> before the <STRONG>wnoutrefresh()</STRONG> call to guar-
       antee an entire-contents copy anywhere.


</PRE>
<H2>SEE ALSO</H2><PRE>
       <STRONG><A HREF="ncurses.3x.html">curses(3x)</A></STRONG>, <STRONG><A HREF="curs_outopts.3x.html">curs_outopts(3x)</A></STRONG>


                                                       <STRONG><A HREF="curs_refresh.3x.html">curs_refresh(3x)</A></STRONG>
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