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29 * @Id: curs_refresh.3x,v 1.19 2018/07/28 22:59:02 tom Exp @
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41 <H1 class="no-header">curs_refresh 3x</H1>
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>
48 </PRE><H2><a name="h2-NAME">NAME</a></H2><PRE>
49 <STRONG>doupdate</STRONG>, <STRONG>redrawwin</STRONG>, <STRONG>refresh</STRONG>, <STRONG>wnoutrefresh</STRONG>, <STRONG>wredrawln</STRONG>, <STRONG>wrefresh</STRONG> -
50 refresh <STRONG>curses</STRONG> windows and lines
53 </PRE><H2><a name="h2-SYNOPSIS">SYNOPSIS</a></H2><PRE>
54 <STRONG>#include</STRONG> <STRONG><curses.h></STRONG>
56 <STRONG>int</STRONG> <STRONG>refresh(void);</STRONG>
57 <STRONG>int</STRONG> <STRONG>wrefresh(WINDOW</STRONG> <STRONG>*win);</STRONG>
58 <STRONG>int</STRONG> <STRONG>wnoutrefresh(WINDOW</STRONG> <STRONG>*win);</STRONG>
59 <STRONG>int</STRONG> <STRONG>doupdate(void);</STRONG>
60 <STRONG>int</STRONG> <STRONG>redrawwin(WINDOW</STRONG> <STRONG>*win);</STRONG>
61 <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 </PRE><H2><a name="h2-DESCRIPTION">DESCRIPTION</a></H2><PRE>
66 </PRE><H3><a name="h3-refresh_wrefresh">refresh/wrefresh</a></H3><PRE>
67 The <STRONG>refresh</STRONG> and <STRONG>wrefresh</STRONG> routines (or <STRONG>wnoutrefresh</STRONG> and <STRONG>doupdate</STRONG>) must
68 be called to get actual output to the terminal, as other routines mere-
69 ly manipulate data structures. The routine <STRONG>wrefresh</STRONG> copies the named
70 window to the <EM>physical</EM> <EM>screen</EM>, taking into account what is already
71 there to do optimizations. The <STRONG>refresh</STRONG> routine is the same, using <STRONG>std-</STRONG>
72 <STRONG>scr</STRONG> as the default window. Unless <STRONG>leaveok</STRONG> has been enabled, the physi-
73 cal cursor of the terminal is left at the location of the cursor for
77 </PRE><H3><a name="h3-wnoutrefresh_doupdate">wnoutrefresh/doupdate</a></H3><PRE>
78 The <STRONG>wnoutrefresh</STRONG> and <STRONG>doupdate</STRONG> routines allow multiple updates with more
79 efficiency than <STRONG>wrefresh</STRONG> alone. In addition to all the window struc-
80 tures, <STRONG>curses</STRONG> keeps two data structures representing the terminal
83 <STRONG>o</STRONG> a <EM>physical</EM> <EM>screen</EM>, describing what is actually on the screen, and
85 <STRONG>o</STRONG> a <EM>virtual</EM> <EM>screen</EM>, describing what the programmer wants to have on
88 The routine <STRONG>wrefresh</STRONG> works by
90 <STRONG>o</STRONG> first calling <STRONG>wnoutrefresh</STRONG>, which copies the named window to the
91 <EM>virtual</EM> <EM>screen</EM>, and
93 <STRONG>o</STRONG> then calling <STRONG>doupdate</STRONG>, which compares the <EM>virtual</EM> <EM>screen</EM> to the
94 <EM>physical</EM> <EM>screen</EM> and does the actual update.
96 If the programmer wishes to output several windows at once, a series of
97 calls to <STRONG>wrefresh</STRONG> results in alternating calls to <STRONG>wnoutrefresh</STRONG> and
98 <STRONG>doupdate</STRONG>, causing several bursts of output to the screen. By first
99 calling <STRONG>wnoutrefresh</STRONG> for each window, it is then possible to call <STRONG>doup-</STRONG>
100 <STRONG>date</STRONG> once, resulting in only one burst of output, with fewer total
101 characters transmitted and less CPU time used.
103 If the <EM>win</EM> argument to <STRONG>wrefresh</STRONG> is the <EM>physical</EM> <EM>screen</EM> (i.e., the glob-
104 al variable <STRONG>curscr</STRONG>), the screen is immediately cleared and repainted
107 The phrase "copies the named window to the virtual screen" above is am-
108 biguous. What actually happens is that all <EM>touched</EM> (changed) lines in
109 the window are copied to the virtual screen. This affects programs
110 that use overlapping windows; it means that if two windows overlap, you
111 can refresh them in either order and the overlap region will be modi-
112 fied only when it is explicitly changed. (But see the section on
113 <STRONG>PORTABILITY</STRONG> below for a warning about exploiting this behavior.)
116 </PRE><H3><a name="h3-wredrawln_redrawwin">wredrawln/redrawwin</a></H3><PRE>
117 The <STRONG>wredrawln</STRONG> routine indicates to <STRONG>curses</STRONG> that some screen lines are
118 corrupted and should be thrown away before anything is written over
119 them. It touches the indicated lines (marking them changed). The rou-
120 tine <STRONG>redrawwin</STRONG> touches the entire window.
123 </PRE><H2><a name="h2-RETURN-VALUE">RETURN VALUE</a></H2><PRE>
124 Routines that return an integer return <STRONG>ERR</STRONG> upon failure, and <STRONG>OK</STRONG> (SVr4
125 only specifies "an integer value other than <STRONG>ERR</STRONG>") upon successful com-
128 X/Open does not define any error conditions. In this implementation
130 <STRONG>wnoutrefresh</STRONG>
131 returns an error if the window pointer is null, or if the win-
134 <STRONG>wredrawln</STRONG>
135 returns an error if the associated call to <STRONG>touchln</STRONG> returns an
139 </PRE><H2><a name="h2-NOTES">NOTES</a></H2><PRE>
140 Note that <STRONG>refresh</STRONG> and <STRONG>redrawwin</STRONG> may be macros.
143 </PRE><H2><a name="h2-PORTABILITY">PORTABILITY</a></H2><PRE>
144 The XSI Curses standard, Issue 4 describes these functions.
146 Whether <STRONG>wnoutrefresh</STRONG> copies to the virtual screen the entire contents
147 of a window or just its changed portions has never been well-documented
148 in historic curses versions (including SVr4). It might be unwise to
149 rely on either behavior in programs that might have to be linked with
150 other curses implementations. Instead, you can do an explicit <STRONG>touchwin</STRONG>
151 before the <STRONG>wnoutrefresh</STRONG> call to guarantee an entire-contents copy any-
155 </PRE><H2><a name="h2-SEE-ALSO">SEE ALSO</a></H2><PRE>
156 <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>.
160 <STRONG><A HREF="curs_refresh.3x.html">curs_refresh(3x)</A></STRONG>
164 <li><a href="#h2-NAME">NAME</a></li>
165 <li><a href="#h2-SYNOPSIS">SYNOPSIS</a></li>
166 <li><a href="#h2-DESCRIPTION">DESCRIPTION</a>
168 <li><a href="#h3-refresh_wrefresh">refresh/wrefresh</a></li>
169 <li><a href="#h3-wnoutrefresh_doupdate">wnoutrefresh/doupdate</a></li>
170 <li><a href="#h3-wredrawln_redrawwin">wredrawln/redrawwin</a></li>
173 <li><a href="#h2-RETURN-VALUE">RETURN VALUE</a></li>
174 <li><a href="#h2-NOTES">NOTES</a></li>
175 <li><a href="#h2-PORTABILITY">PORTABILITY</a></li>
176 <li><a href="#h2-SEE-ALSO">SEE ALSO</a></li>