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30 * @Id: curs_refresh.3x,v 1.25 2022/02/12 20:05:11 tom Exp @
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42 <H1 class="no-header">curs_refresh 3x</H1>
44 <STRONG><A HREF="curs_refresh.3x.html">curs_refresh(3x)</A></STRONG> <STRONG><A HREF="curs_refresh.3x.html">curs_refresh(3x)</A></STRONG>
49 </PRE><H2><a name="h2-NAME">NAME</a></H2><PRE>
50 <STRONG>doupdate</STRONG>, <STRONG>redrawwin</STRONG>, <STRONG>refresh</STRONG>, <STRONG>wnoutrefresh</STRONG>, <STRONG>wredrawln</STRONG>, <STRONG>wrefresh</STRONG> -
51 refresh <STRONG>curses</STRONG> windows and lines
54 </PRE><H2><a name="h2-SYNOPSIS">SYNOPSIS</a></H2><PRE>
55 <STRONG>#include</STRONG> <STRONG><curses.h></STRONG>
57 <STRONG>int</STRONG> <STRONG>refresh(void);</STRONG>
58 <STRONG>int</STRONG> <STRONG>wrefresh(WINDOW</STRONG> <STRONG>*</STRONG><EM>win</EM><STRONG>);</STRONG>
59 <STRONG>int</STRONG> <STRONG>wnoutrefresh(WINDOW</STRONG> <STRONG>*</STRONG><EM>win</EM><STRONG>);</STRONG>
60 <STRONG>int</STRONG> <STRONG>doupdate(void);</STRONG>
62 <STRONG>int</STRONG> <STRONG>redrawwin(WINDOW</STRONG> <STRONG>*</STRONG><EM>win</EM><STRONG>);</STRONG>
63 <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>
66 </PRE><H2><a name="h2-DESCRIPTION">DESCRIPTION</a></H2><PRE>
68 </PRE><H3><a name="h3-refresh_wrefresh">refresh/wrefresh</a></H3><PRE>
69 The <STRONG>refresh</STRONG> and <STRONG>wrefresh</STRONG> routines (or <STRONG>wnoutrefresh</STRONG> and <STRONG>doupdate</STRONG>) must
70 be called to get actual output to the terminal, as other routines mere-
71 ly manipulate data structures. The routine <STRONG>wrefresh</STRONG> copies the named
72 window to the <EM>physical</EM> <EM>screen</EM>, taking into account what is already
73 there to do optimizations. The <STRONG>refresh</STRONG> routine is the same, using <STRONG>std-</STRONG>
74 <STRONG>scr</STRONG> as the default window. Unless <STRONG>leaveok</STRONG> has been enabled, the physi-
75 cal cursor of the terminal is left at the location of the cursor for
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 updates with more
81 efficiency than <STRONG>wrefresh</STRONG> alone. In addition to all the window struc-
82 tures, <STRONG>curses</STRONG> keeps two data structures representing the terminal
85 <STRONG>o</STRONG> a <EM>physical</EM> <EM>screen</EM>, describing what is actually on the screen, and
87 <STRONG>o</STRONG> a <EM>virtual</EM> <EM>screen</EM>, describing what the programmer wants to have on
90 The routine <STRONG>wrefresh</STRONG> works by
92 <STRONG>o</STRONG> first calling <STRONG>wnoutrefresh</STRONG>, which copies the named window to the
93 <EM>virtual</EM> <EM>screen</EM>, and
95 <STRONG>o</STRONG> then calling <STRONG>doupdate</STRONG>, which compares the <EM>virtual</EM> <EM>screen</EM> to the
96 <EM>physical</EM> <EM>screen</EM> and does the actual update.
98 If the programmer wishes to output several windows at once, a series of
99 calls to <STRONG>wrefresh</STRONG> results in alternating calls to <STRONG>wnoutrefresh</STRONG> and
100 <STRONG>doupdate</STRONG>, causing several bursts of output to the screen. By first
101 calling <STRONG>wnoutrefresh</STRONG> for each window, it is then possible to call <STRONG>doup-</STRONG>
102 <STRONG>date</STRONG> once, resulting in only one burst of output, with fewer total
103 characters transmitted and less CPU time used.
105 If the <EM>win</EM> argument to <STRONG>wrefresh</STRONG> is the <EM>physical</EM> <EM>screen</EM> (i.e., the glob-
106 al variable <STRONG>curscr</STRONG>), the screen is immediately cleared and repainted
109 The phrase "copies the named window to the virtual screen" above is am-
110 biguous. What actually happens is that all <EM>touched</EM> (changed) lines in
111 the window are copied to the virtual screen. This affects programs
112 that use overlapping windows; it means that if two windows overlap, you
113 can refresh them in either order and the overlap region will be modi-
114 fied only when it is explicitly changed. (But see the section on
115 <STRONG>PORTABILITY</STRONG> below for a warning about exploiting this behavior.)
118 </PRE><H3><a name="h3-wredrawln_redrawwin">wredrawln/redrawwin</a></H3><PRE>
119 The <STRONG>wredrawln</STRONG> routine indicates to <STRONG>curses</STRONG> that some screen lines are
120 corrupted and should be thrown away before anything is written over
121 them. It touches the indicated lines (marking them changed). The rou-
122 tine <STRONG>redrawwin</STRONG> touches the entire window.
125 </PRE><H2><a name="h2-RETURN-VALUE">RETURN VALUE</a></H2><PRE>
126 Routines that return an integer return <STRONG>ERR</STRONG> upon failure, and <STRONG>OK</STRONG> (SVr4
127 only specifies "an integer value other than <STRONG>ERR</STRONG>") upon successful com-
130 X/Open does not define any error conditions. In this implementation
132 <STRONG>wnoutrefresh</STRONG>
133 returns an error if the window pointer is null, or if the win-
136 <STRONG>wredrawln</STRONG>
137 returns an error if the associated call to <STRONG>touchln</STRONG> returns an
141 </PRE><H2><a name="h2-NOTES">NOTES</a></H2><PRE>
142 Note that <STRONG>refresh</STRONG> and <STRONG>redrawwin</STRONG> may be macros.
145 </PRE><H2><a name="h2-PORTABILITY">PORTABILITY</a></H2><PRE>
146 The XSI Curses standard, Issue 4 describes these functions.
148 Whether <STRONG>wnoutrefresh</STRONG> copies to the virtual screen the entire contents
149 of a window or just its changed portions has never been well-documented
150 in historic curses versions (including SVr4). It might be unwise to
151 rely on either behavior in programs that might have to be linked with
152 other curses implementations. Instead, you can do an explicit <STRONG>touchwin</STRONG>
153 before the <STRONG>wnoutrefresh</STRONG> call to guarantee an entire-contents copy any-
157 </PRE><H2><a name="h2-SEE-ALSO">SEE ALSO</a></H2><PRE>
158 <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>.
162 <STRONG><A HREF="curs_refresh.3x.html">curs_refresh(3x)</A></STRONG>
166 <li><a href="#h2-NAME">NAME</a></li>
167 <li><a href="#h2-SYNOPSIS">SYNOPSIS</a></li>
168 <li><a href="#h2-DESCRIPTION">DESCRIPTION</a>
170 <li><a href="#h3-refresh_wrefresh">refresh/wrefresh</a></li>
171 <li><a href="#h3-wnoutrefresh_doupdate">wnoutrefresh/doupdate</a></li>
172 <li><a href="#h3-wredrawln_redrawwin">wredrawln/redrawwin</a></li>
175 <li><a href="#h2-RETURN-VALUE">RETURN VALUE</a></li>
176 <li><a href="#h2-NOTES">NOTES</a></li>
177 <li><a href="#h2-PORTABILITY">PORTABILITY</a></li>
178 <li><a href="#h2-SEE-ALSO">SEE ALSO</a></li>