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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>,
50 <STRONG>wrefresh</STRONG> - 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
68 <STRONG>doupdate</STRONG>) must be called to get actual output to the ter-
69 minal, as other routines merely manipulate data struc-
70 tures. The routine <STRONG>wrefresh</STRONG> copies the named window to
71 the physical terminal screen, taking into account what is
72 already there to do optimizations. The <STRONG>refresh</STRONG> routine is
73 the same, using <STRONG>stdscr</STRONG> as the default window. Unless
74 <STRONG>leaveok</STRONG> has been enabled, the physical cursor of the ter-
75 minal is left at the location of the cursor for that win-
79 </PRE><H3><a name="h3-wnoutrefresh_doupdate">wnoutrefresh/doupdate</a></H3><PRE>
80 The <STRONG>wnoutrefresh</STRONG> and <STRONG>doupdate</STRONG> routines allow multiple up-
81 dates with more efficiency than <STRONG>wrefresh</STRONG> alone. In addi-
82 tion to all the window structures, <STRONG>curses</STRONG> keeps two data
83 structures representing the terminal screen: a physical
84 screen, describing what is actually on the screen, and a
85 virtual screen, describing what the programmer wants to
88 The routine <STRONG>wrefresh</STRONG> works by first calling <STRONG>wnoutrefresh</STRONG>,
89 which copies the named window to the virtual screen, and
90 then calling <STRONG>doupdate</STRONG>, which compares the virtual screen
91 to the physical screen and does the actual update. If the
92 programmer wishes to output several windows at once, a se-
93 ries of calls to <STRONG>wrefresh</STRONG> results in alternating calls to
94 <STRONG>wnoutrefresh</STRONG> and <STRONG>doupdate</STRONG>, causing several bursts of out-
95 put to the screen. By first calling <STRONG>wnoutrefresh</STRONG> for each
96 window, it is then possible to call <STRONG>doupdate</STRONG> once, result-
97 ing in only one burst of output, with fewer total charac-
98 ters transmitted and less CPU time used. If the <EM>win</EM> argu-
99 ment to <STRONG>wrefresh</STRONG> is the global variable <STRONG>curscr</STRONG>, the screen
100 is immediately cleared and repainted from scratch.
102 The phrase "copies the named window to the virtual screen"
103 above is ambiguous. What actually happens is that all
104 <EM>touched</EM> (changed) lines in the window are copied to the
105 virtual screen. This affects programs that use overlap-
106 ping windows; it means that if two windows overlap, you
107 can refresh them in either order and the overlap region
108 will be modified only when it is explicitly changed. (But
109 see the section on <STRONG>PORTABILITY</STRONG> below for a warning about
110 exploiting this behavior.)
113 </PRE><H3><a name="h3-wredrawln_redrawwin">wredrawln/redrawwin</a></H3><PRE>
114 The <STRONG>wredrawln</STRONG> routine indicates to <STRONG>curses</STRONG> that some screen
115 lines are corrupted and should be thrown away before any-
116 thing is written over them. It touches the indicated
117 lines (marking them changed). The routine <STRONG>redrawwin</STRONG>
118 touches the entire window.
121 </PRE><H2><a name="h2-RETURN-VALUE">RETURN VALUE</a></H2><PRE>
122 Routines that return an integer return <STRONG>ERR</STRONG> upon failure,
123 and <STRONG>OK</STRONG> (SVr4 only specifies "an integer value other than
124 <STRONG>ERR</STRONG>") upon successful completion.
126 X/Open does not define any error conditions. In this im-
129 <STRONG>wnoutrefresh</STRONG>
130 returns an error if the window pointer is null, or
131 if the window is really a pad.
133 <STRONG>wredrawln</STRONG>
134 returns an error if the associated call to <STRONG>touchln</STRONG>
138 </PRE><H2><a name="h2-NOTES">NOTES</a></H2><PRE>
139 Note that <STRONG>refresh</STRONG> and <STRONG>redrawwin</STRONG> may be macros.
142 </PRE><H2><a name="h2-PORTABILITY">PORTABILITY</a></H2><PRE>
143 The XSI Curses standard, Issue 4 describes these func-
146 Whether <STRONG>wnoutrefresh</STRONG> copies to the virtual screen the en-
147 tire contents of a window or just its changed portions has
148 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 guarantee
153 an entire-contents copy anywhere.
156 </PRE><H2><a name="h2-SEE-ALSO">SEE ALSO</a></H2><PRE>
157 <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>.
161 <STRONG><A HREF="curs_refresh.3x.html">curs_refresh(3x)</A></STRONG>
165 <li><a href="#h2-NAME">NAME</a></li>
166 <li><a href="#h2-SYNOPSIS">SYNOPSIS</a></li>
167 <li><a href="#h2-DESCRIPTION">DESCRIPTION</a>
169 <li><a href="#h3-refresh_wrefresh">refresh/wrefresh</a></li>
170 <li><a href="#h3-wnoutrefresh_doupdate">wnoutrefresh/doupdate</a></li>
171 <li><a href="#h3-wredrawln_redrawwin">wredrawln/redrawwin</a></li>
174 <li><a href="#h2-RETURN-VALUE">RETURN VALUE</a></li>
175 <li><a href="#h2-NOTES">NOTES</a></li>
176 <li><a href="#h2-PORTABILITY">PORTABILITY</a></li>
177 <li><a href="#h2-SEE-ALSO">SEE ALSO</a></li>