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<H1 class="no-header">curs_refresh 3x</H1>
<PRE>
<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><a name="h2-NAME">NAME</a></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><a name="h2-SYNOPSIS">SYNOPSIS</a></H2><PRE>
<STRONG>#include</STRONG> <STRONG><curses.h></STRONG>
<STRONG>int</STRONG> <STRONG>refresh(void);</STRONG>
<STRONG>int</STRONG> <STRONG>wrefresh(WINDOW</STRONG> <STRONG>*</STRONG><EM>win</EM><STRONG>);</STRONG>
<STRONG>int</STRONG> <STRONG>wnoutrefresh(WINDOW</STRONG> <STRONG>*</STRONG><EM>win</EM><STRONG>);</STRONG>
<STRONG>int</STRONG> <STRONG>doupdate(void);</STRONG>
<STRONG>int</STRONG> <STRONG>redrawwin(WINDOW</STRONG> <STRONG>*</STRONG><EM>win</EM><STRONG>);</STRONG>
<STRONG>int</STRONG> <STRONG>wredrawln(WINDOW</STRONG> <STRONG>*</STRONG><EM>win</EM><STRONG>,</STRONG> <STRONG>int</STRONG> <EM>beg</EM><STRONG>_</STRONG><EM>line</EM><STRONG>,</STRONG> <STRONG>int</STRONG> <EM>num</EM><STRONG>_</STRONG><EM>lines</EM><STRONG>);</STRONG>
</PRE><H2><a name="h2-DESCRIPTION">DESCRIPTION</a></H2><PRE>
</PRE><H3><a name="h3-refresh_wrefresh">refresh/wrefresh</a></H3><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 terminal, as other routines mere-
ly manipulate data structures. The routine <STRONG>wrefresh</STRONG> copies the named
window to the <EM>physical</EM> <EM>screen</EM>, taking into account what is already
there to do optimizations. The <STRONG>refresh</STRONG> routine is the same, using <STRONG>std-</STRONG>
<STRONG>scr</STRONG> as the default window. Unless <STRONG>leaveok</STRONG> has been enabled, the physi-
cal cursor of the terminal is left at the location of the cursor for
that window.
</PRE><H3><a name="h3-wnoutrefresh_doupdate">wnoutrefresh/doupdate</a></H3><PRE>
The <STRONG>wnoutrefresh</STRONG> and <STRONG>doupdate</STRONG> routines allow multiple updates with more
efficiency than <STRONG>wrefresh</STRONG> alone. In addition to all the window struc-
tures, <STRONG>curses</STRONG> keeps two data structures representing the terminal
screen:
<STRONG>o</STRONG> a <EM>physical</EM> <EM>screen</EM>, describing what is actually on the screen, and
<STRONG>o</STRONG> a <EM>virtual</EM> <EM>screen</EM>, describing what the programmer wants to have on
the screen.
The routine <STRONG>wrefresh</STRONG> works by
<STRONG>o</STRONG> first calling <STRONG>wnoutrefresh</STRONG>, which copies the named window to the
<EM>virtual</EM> <EM>screen</EM>, and
<STRONG>o</STRONG> then calling <STRONG>doupdate</STRONG>, which compares the <EM>virtual</EM> <EM>screen</EM> to the
<EM>physical</EM> <EM>screen</EM> and does the actual update.
If the programmer wishes to output several windows at once, a series of
calls to <STRONG>wrefresh</STRONG> results in alternating calls to <STRONG>wnoutrefresh</STRONG> and
<STRONG>doupdate</STRONG>, causing several bursts of output to the screen. By first
calling <STRONG>wnoutrefresh</STRONG> for each window, it is then possible to call <STRONG>doup-</STRONG>
<STRONG>date</STRONG> once, resulting in only one burst of output, with fewer total
characters transmitted and less CPU time used.
If the <EM>win</EM> argument to <STRONG>wrefresh</STRONG> is the <EM>physical</EM> <EM>screen</EM> (i.e., the glob-
al 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 am-
biguous. 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 overlapping windows; it means that if two windows overlap, you
can refresh them in either order and the overlap region will be modi-
fied only when it is explicitly changed. (But see the section on
<STRONG>PORTABILITY</STRONG> below for a warning about exploiting this behavior.)
</PRE><H3><a name="h3-wredrawln_redrawwin">wredrawln/redrawwin</a></H3><PRE>
The <STRONG>wredrawln</STRONG> routine indicates to <STRONG>curses</STRONG> 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 rou-
tine <STRONG>redrawwin</STRONG> touches the entire window.
</PRE><H2><a name="h2-RETURN-VALUE">RETURN VALUE</a></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 com-
pletion.
X/Open does not define any error conditions. In this implementation
<STRONG>wnoutrefresh</STRONG>
returns an error if the window pointer is null, or if the win-
dow is really a pad.
<STRONG>wredrawln</STRONG>
returns an error if the associated call to <STRONG>touchln</STRONG> returns an
error.
</PRE><H2><a name="h2-NOTES">NOTES</a></H2><PRE>
Note that <STRONG>refresh</STRONG> and <STRONG>redrawwin</STRONG> may be macros.
</PRE><H2><a name="h2-PORTABILITY">PORTABILITY</a></H2><PRE>
The XSI Curses standard, Issue 4 describes these functions.
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 explicit <STRONG>touchwin</STRONG>
before the <STRONG>wnoutrefresh</STRONG> call to guarantee an entire-contents copy any-
where.
</PRE><H2><a name="h2-SEE-ALSO">SEE ALSO</a></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_variables.3x.html">curs_variables(3x)</A></STRONG>.
<STRONG><A HREF="curs_refresh.3x.html">curs_refresh(3x)</A></STRONG>
</PRE>
<div class="nav">
<ul>
<li><a href="#h2-NAME">NAME</a></li>
<li><a href="#h2-SYNOPSIS">SYNOPSIS</a></li>
<li><a href="#h2-DESCRIPTION">DESCRIPTION</a>
<ul>
<li><a href="#h3-refresh_wrefresh">refresh/wrefresh</a></li>
<li><a href="#h3-wnoutrefresh_doupdate">wnoutrefresh/doupdate</a></li>
<li><a href="#h3-wredrawln_redrawwin">wredrawln/redrawwin</a></li>
</ul>
</li>
<li><a href="#h2-RETURN-VALUE">RETURN VALUE</a></li>
<li><a href="#h2-NOTES">NOTES</a></li>
<li><a href="#h2-PORTABILITY">PORTABILITY</a></li>
<li><a href="#h2-SEE-ALSO">SEE ALSO</a></li>
</ul>
</div>
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