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29 * @Id: curs_refresh.3x,v 1.17 2016/10/15 16:45:45 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 physical terminal screen, taking into account what is al-
71 ready there to do optimizations. The <STRONG>refresh</STRONG> routine is the same, us-
72 ing <STRONG>stdscr</STRONG> as the default window. Unless <STRONG>leaveok</STRONG> has been enabled, the
73 physical cursor of the terminal is left at the location of the cursor
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
81 screen: a physical screen, describing what is actually on the screen,
82 and a virtual screen, describing what the programmer wants to have on
85 The routine <STRONG>wrefresh</STRONG> works by first calling <STRONG>wnoutrefresh</STRONG>, which copies
86 the named window to the virtual screen, and then calling <STRONG>doupdate</STRONG>,
87 which compares the virtual screen to the physical screen and does the
88 actual update. If the programmer wishes to output several windows at
89 once, a series of calls to <STRONG>wrefresh</STRONG> results in alternating calls to
90 <STRONG>wnoutrefresh</STRONG> and <STRONG>doupdate</STRONG>, causing several bursts of output to the
91 screen. By first calling <STRONG>wnoutrefresh</STRONG> for each window, it is then pos-
92 sible to call <STRONG>doupdate</STRONG> once, resulting in only one burst of output,
93 with fewer total characters transmitted and less CPU time used. If the
94 <EM>win</EM> argument to <STRONG>wrefresh</STRONG> is the global variable <STRONG>curscr</STRONG>, the screen is
95 immediately cleared and repainted from scratch.
97 The phrase "copies the named window to the virtual screen" above is am-
98 biguous. What actually happens is that all <EM>touched</EM> (changed) lines in
99 the window are copied to the virtual screen. This affects programs
100 that use overlapping windows; it means that if two windows overlap, you
101 can refresh them in either order and the overlap region will be modi-
102 fied only when it is explicitly changed. (But see the section on
103 <STRONG>PORTABILITY</STRONG> below for a warning about exploiting this behavior.)
106 </PRE><H3><a name="h3-wredrawln_redrawwin">wredrawln/redrawwin</a></H3><PRE>
107 The <STRONG>wredrawln</STRONG> routine indicates to <STRONG>curses</STRONG> that some screen lines are
108 corrupted and should be thrown away before anything is written over
109 them. It touches the indicated lines (marking them changed). The rou-
110 tine <STRONG>redrawwin</STRONG> touches the entire window.
113 </PRE><H2><a name="h2-RETURN-VALUE">RETURN VALUE</a></H2><PRE>
114 Routines that return an integer return <STRONG>ERR</STRONG> upon failure, and <STRONG>OK</STRONG> (SVr4
115 only specifies "an integer value other than <STRONG>ERR</STRONG>") upon successful com-
118 X/Open does not define any error conditions. In this implementation
120 <STRONG>wnoutrefresh</STRONG>
121 returns an error if the window pointer is null, or if the win-
124 <STRONG>wredrawln</STRONG>
125 returns an error if the associated call to <STRONG>touchln</STRONG> returns an
129 </PRE><H2><a name="h2-NOTES">NOTES</a></H2><PRE>
130 Note that <STRONG>refresh</STRONG> and <STRONG>redrawwin</STRONG> may be macros.
133 </PRE><H2><a name="h2-PORTABILITY">PORTABILITY</a></H2><PRE>
134 The XSI Curses standard, Issue 4 describes these functions.
136 Whether <STRONG>wnoutrefresh</STRONG> copies to the virtual screen the entire contents
137 of a window or just its changed portions has never been well-documented
138 in historic curses versions (including SVr4). It might be unwise to
139 rely on either behavior in programs that might have to be linked with
140 other curses implementations. Instead, you can do an explicit <STRONG>touchwin</STRONG>
141 before the <STRONG>wnoutrefresh</STRONG> call to guarantee an entire-contents copy any-
145 </PRE><H2><a name="h2-SEE-ALSO">SEE ALSO</a></H2><PRE>
146 <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>.
150 <STRONG><A HREF="curs_refresh.3x.html">curs_refresh(3x)</A></STRONG>
154 <li><a href="#h2-NAME">NAME</a></li>
155 <li><a href="#h2-SYNOPSIS">SYNOPSIS</a></li>
156 <li><a href="#h2-DESCRIPTION">DESCRIPTION</a>
158 <li><a href="#h3-refresh_wrefresh">refresh/wrefresh</a></li>
159 <li><a href="#h3-wnoutrefresh_doupdate">wnoutrefresh/doupdate</a></li>
160 <li><a href="#h3-wredrawln_redrawwin">wredrawln/redrawwin</a></li>
163 <li><a href="#h2-RETURN-VALUE">RETURN VALUE</a></li>
164 <li><a href="#h2-NOTES">NOTES</a></li>
165 <li><a href="#h2-PORTABILITY">PORTABILITY</a></li>
166 <li><a href="#h2-SEE-ALSO">SEE ALSO</a></li>