release/src/router/libncurses/doc/html/man/curs_refresh.3x.html

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  41 <H1 class="no-header">curs_refresh 3x</H1>
  42 <PRE>
  43 <STRONG><A HREF="curs_refresh.3x.html">curs_refresh(3x)</A></STRONG>                                       <STRONG><A HREF="curs_refresh.3x.html">curs_refresh(3x)</A></STRONG>
  44
  45
  46
  47
  48 </PRE>
  49 <H2><a name="h2-NAME">NAME</a></H2><PRE>
  50        <STRONG>doupdate</STRONG>, <STRONG>redrawwin</STRONG>, <STRONG>refresh</STRONG>, <STRONG>wnoutrefresh</STRONG>, <STRONG>wredrawln</STRONG>,
  51        <STRONG>wrefresh</STRONG> - refresh <STRONG>curses</STRONG> windows and lines
  52
  53
  54 </PRE>
  55 <H2><a name="h2-SYNOPSIS">SYNOPSIS</a></H2><PRE>
  56        <STRONG>#include</STRONG> <STRONG>&lt;curses.h&gt;</STRONG>
  57
  58        <STRONG>int</STRONG> <STRONG>refresh(void);</STRONG>
  59        <STRONG>int</STRONG> <STRONG>wrefresh(WINDOW</STRONG> <STRONG>*win);</STRONG>
  60        <STRONG>int</STRONG> <STRONG>wnoutrefresh(WINDOW</STRONG> <STRONG>*win);</STRONG>
  61        <STRONG>int</STRONG> <STRONG>doupdate(void);</STRONG>
  62        <STRONG>int</STRONG> <STRONG>redrawwin(WINDOW</STRONG> <STRONG>*win);</STRONG>
  63        <STRONG>int</STRONG> <STRONG>wredrawln(WINDOW</STRONG> <STRONG>*win,</STRONG> <STRONG>int</STRONG> <STRONG>beg_line,</STRONG> <STRONG>int</STRONG> <STRONG>num_lines);</STRONG>
  64
  65
  66 </PRE>
  67 <H2><a name="h2-DESCRIPTION">DESCRIPTION</a></H2><PRE>
  68        The <STRONG>refresh</STRONG> and <STRONG>wrefresh</STRONG>  routines  (or  <STRONG>wnoutrefresh</STRONG>  and
  69        <STRONG>doupdate</STRONG>)  must be called to get actual output to the ter-
  70        minal, as other routines  merely  manipulate  data  struc-
  71        tures.   The  routine  <STRONG>wrefresh</STRONG> copies the named window to
  72        the physical terminal screen, taking into account what  is
  73        already there to do optimizations.  The <STRONG>refresh</STRONG> routine is
  74        the same, using <STRONG>stdscr</STRONG>  as  the  default  window.   Unless
  75        <STRONG>leaveok</STRONG>  has been enabled, the physical cursor of the ter-
  76        minal is left at the location of the cursor for that  win-
  77        dow.
  78
  79        The  <STRONG>wnoutrefresh</STRONG> and <STRONG>doupdate</STRONG> routines allow multiple up-
  80        dates with more efficiency than <STRONG>wrefresh</STRONG> alone.  In  addi-
  81        tion  to  all the window structures, <STRONG>curses</STRONG> keeps two data
  82        structures representing the terminal  screen:  a  physical
  83        screen,  describing  what is actually on the screen, and a
  84        virtual screen, describing what the  programmer  wants  to
  85        have on the screen.
  86
  87        The  routine <STRONG>wrefresh</STRONG> works by first calling <STRONG>wnoutrefresh</STRONG>,
  88        which copies the named window to the virtual  screen,  and
  89        then  calling  <STRONG>doupdate</STRONG>, which compares the virtual screen
  90        to the physical screen and does the actual update.  If the
  91        programmer wishes to output several windows at once, a se-
  92        ries of calls to <STRONG>wrefresh</STRONG> results in alternating calls  to
  93        <STRONG>wnoutrefresh</STRONG>  and <STRONG>doupdate</STRONG>, causing several bursts of out-
  94        put to the screen.  By first calling <STRONG>wnoutrefresh</STRONG> for each
  95        window, it is then possible to call <STRONG>doupdate</STRONG> once, result-
  96        ing in only one burst of output, with fewer total  charac-
  97        ters transmitted and less CPU time used.  If the <EM>win</EM> argu-
  98        ment to <STRONG>wrefresh</STRONG> is the global variable <STRONG>curscr</STRONG>, the screen
  99        is immediately cleared and repainted from scratch.
 100
 101        The phrase "copies the named window to the virtual screen"
 102        above is ambiguous.  What actually  happens  is  that  all
 103        <EM>touched</EM>  (changed)  lines  in the window are copied to the
 104        virtual screen.  This affects programs that  use  overlap-
 105        ping  windows;  it  means that if two windows overlap, you
 106        can refresh them in either order and  the  overlap  region
 107        will be modified only when it is explicitly changed.  (But
 108        see the section on <STRONG>PORTABILITY</STRONG> below for a  warning  about
 109        exploiting this behavior.)
 110
 111        The <STRONG>wredrawln</STRONG> routine indicates to <STRONG>curses</STRONG> that some screen
 112        lines are corrupted and should be thrown away before  any-
 113        thing  is  written  over  them.   It touches the indicated
 114        lines (marking them  changed).   The  routine  <STRONG>redrawwin</STRONG>()
 115        touches the entire window.
 116
 117
 118 </PRE>
 119 <H2><a name="h2-RETURN-VALUE">RETURN VALUE</a></H2><PRE>
 120        Routines  that  return an integer return <STRONG>ERR</STRONG> upon failure,
 121        and <STRONG>OK</STRONG> (SVr4 only specifies "an integer value  other  than
 122        <STRONG>ERR</STRONG>") upon successful completion.
 123
 124        X/Open  does not define any error conditions.  In this im-
 125        plementation
 126
 127               <STRONG>wnoutrefresh</STRONG>
 128                    returns an error  if  the  window  pointer  is
 129                    null, or if the window is really a pad.
 130
 131               <STRONG>wredrawln</STRONG>
 132                    returns  an  error  if  the associated call to
 133                    <STRONG>touchln</STRONG> returns an error.
 134
 135
 136 </PRE>
 137 <H2><a name="h2-NOTES">NOTES</a></H2><PRE>
 138        Note that <STRONG>refresh</STRONG> and <STRONG>redrawwin</STRONG> may be macros.
 139
 140
 141 </PRE>
 142 <H2><a name="h2-PORTABILITY">PORTABILITY</a></H2><PRE>
 143        The XSI Curses standard, Issue  4  describes  these  func-
 144        tions.
 145
 146        Whether  <STRONG>wnoutrefresh()</STRONG>  copies  to the virtual screen the
 147        entire contents of a window or just its  changed  portions
 148        has never been well-documented in historic curses versions
 149        (including SVr4).  It might be unwise to  rely  on  either
 150        behavior  in  programs  that  might have to be linked with
 151        other curses implementations.  Instead, you can do an  ex-
 152        plicit  <STRONG>touchwin()</STRONG> before the <STRONG>wnoutrefresh()</STRONG> call to guar-
 153        antee an entire-contents copy anywhere.
 154
 155
 156 </PRE>
 157 <H2><a name="h2-SEE-ALSO">SEE ALSO</a></H2><PRE>
 158        <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_variables.3x.html">curs_variables(3x)</A></STRONG>.
 159
 160
 161
 162                                                        <STRONG><A HREF="curs_refresh.3x.html">curs_refresh(3x)</A></STRONG>
 163 </PRE>
 164 <div class="nav">
 165 <ul>
 166 <li><a href="#h2-NAME">NAME</a></li>
 167 <li><a href="#h2-SYNOPSIS">SYNOPSIS</a></li>
 168 <li><a href="#h2-DESCRIPTION">DESCRIPTION</a></li>
 169 <li><a href="#h2-RETURN-VALUE">RETURN VALUE</a></li>
 170 <li><a href="#h2-NOTES">NOTES</a></li>
 171 <li><a href="#h2-PORTABILITY">PORTABILITY</a></li>
 172 <li><a href="#h2-SEE-ALSO">SEE ALSO</a></li>
 173 </ul>
 174 </div>
 175 </BODY>
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