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<H1 class="no-header">curs_refresh 3x 2025-01-18 ncurses 6.6 Library calls</H1>
<PRE>
<STRONG><A HREF="curs_refresh.3x.html">curs_refresh(3x)</A></STRONG> Library calls <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 <EM>curses</EM> windows or lines thereupon
</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
merely 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>stdscr</STRONG> as the default window. Unless <STRONG><A HREF="leaveok.3x.html">leaveok(3x)</A></STRONG> has been
enabled, the physical 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
structures, <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>doupdate</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
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 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
<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
routine <STRONG>redrawwin</STRONG> touches the entire window.
</PRE><H2><a name="h2-RETURN-VALUE">RETURN VALUE</a></H2><PRE>
These routines return the integer <STRONG>ERR</STRONG> upon failure and <STRONG>OK</STRONG>
In this implementation
<STRONG>wnoutrefresh</STRONG>
returns <STRONG>ERR</STRONG> if the window pointer is null, or if the window is
really a pad.
<STRONG>wredrawln</STRONG>
return <STRONG>ERR</STRONG> if the associated call to <STRONG>touchln</STRONG> returns <STRONG>ERR</STRONG>.
</PRE><H2><a name="h2-NOTES">NOTES</a></H2><PRE>
<STRONG>refresh</STRONG> and <STRONG>redrawwin</STRONG> may be implemented as macros.
</PRE><H2><a name="h2-PORTABILITY">PORTABILITY</a></H2><PRE>
X/Open Curses Issue 4 describes these functions. It specifies no error
conditions for them.
SVr4 describes a successful return value only as "an integer value
other than <EM>ERR</EM>".
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
anywhere.
</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>
ncurses 6.6 2025-01-18 <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>
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