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30 * @Id: curs_refresh.3x,v 1.46 2024/04/20 21:20:07 tom Exp @
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42 <H1 class="no-header">curs_refresh 3x 2024-04-20 ncurses 6.5 Library calls</H1>
44 <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>
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 <EM>curses</EM> windows or lines thereupon
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
71 merely manipulate data structures. The routine <STRONG>wrefresh</STRONG> copies the
72 named window to the <EM>physical</EM> <EM>screen</EM>, taking into account what is
73 already there to do optimizations. The <STRONG>refresh</STRONG> routine is the same,
74 using <STRONG>stdscr</STRONG> as the default window. Unless <STRONG><A HREF="leaveok.3x.html">leaveok(3x)</A></STRONG> has been
75 enabled, the physical cursor of the terminal is left at the location of
76 the cursor for that window.
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
82 structures, <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
102 <STRONG>doupdate</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
106 global variable <STRONG>curscr</STRONG>), the screen is immediately cleared and
107 repainted from scratch.
109 The phrase "copies the named window to the virtual screen" above is
110 ambiguous. What actually happens is that all <EM>touched</EM> (changed) lines
111 in 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
114 modified 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
122 routine <STRONG>redrawwin</STRONG> touches the entire window.
125 </PRE><H2><a name="h2-RETURN-VALUE">RETURN VALUE</a></H2><PRE>
126 These routines return the integer <STRONG>ERR</STRONG> upon failure and <STRONG>OK</STRONG> (SVr4
127 specifies only "an integer value other than <STRONG>ERR</STRONG>") upon successful
130 X/Open Curses does not specify any error conditions. In this
133 <STRONG>wnoutrefresh</STRONG>
134 returns an error if the window pointer is null, or if the
135 window is really a pad.
137 <STRONG>wredrawln</STRONG>
138 returns an error if the associated call to <STRONG>touchln</STRONG> returns an
142 </PRE><H2><a name="h2-NOTES">NOTES</a></H2><PRE>
143 Note that <STRONG>refresh</STRONG> and <STRONG>redrawwin</STRONG> may be macros.
146 </PRE><H2><a name="h2-PORTABILITY">PORTABILITY</a></H2><PRE>
147 X/Open Curses, Issue 4 describes these functions.
149 Whether <STRONG>wnoutrefresh</STRONG> copies to the virtual screen the entire contents
150 of a window or just its changed portions has never been well-documented
151 in historic curses versions (including SVr4). It might be unwise to
152 rely on either behavior in programs that might have to be linked with
153 other curses implementations. Instead, you can do an explicit <STRONG>touchwin</STRONG>
154 before the <STRONG>wnoutrefresh</STRONG> call to guarantee an entire-contents copy
158 </PRE><H2><a name="h2-SEE-ALSO">SEE ALSO</a></H2><PRE>
159 <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>
163 ncurses 6.5 2024-04-20 <STRONG><A HREF="curs_refresh.3x.html">curs_refresh(3x)</A></STRONG>
167 <li><a href="#h2-NAME">NAME</a></li>
168 <li><a href="#h2-SYNOPSIS">SYNOPSIS</a></li>
169 <li><a href="#h2-DESCRIPTION">DESCRIPTION</a>
171 <li><a href="#h3-refresh_wrefresh">refresh, wrefresh</a></li>
172 <li><a href="#h3-wnoutrefresh_doupdate">wnoutrefresh, doupdate</a></li>
173 <li><a href="#h3-wredrawln_redrawwin">wredrawln, redrawwin</a></li>
176 <li><a href="#h2-RETURN-VALUE">RETURN VALUE</a></li>
177 <li><a href="#h2-NOTES">NOTES</a></li>
178 <li><a href="#h2-PORTABILITY">PORTABILITY</a></li>
179 <li><a href="#h2-SEE-ALSO">SEE ALSO</a></li>