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30 * @Id: curs_refresh.3x,v 1.10 2001/11/03 18:57:12 tom Exp @
34 <TITLE>curs_refresh 3x</TITLE>
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39 <H1>curs_refresh 3x</H1>
42 <!-- Manpage converted by man2html 3.0.1 -->
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>
50 <STRONG>doupdate</STRONG>, <STRONG>redrawwin</STRONG>, <STRONG>refresh</STRONG>, <STRONG>wnoutrefresh</STRONG>, <STRONG>wredrawln</STRONG>,
51 <STRONG>wrefresh</STRONG> - refresh <STRONG>curses</STRONG> windows and lines
55 <H2>SYNOPSIS</H2><PRE>
56 <STRONG>#include</STRONG> <STRONG><curses.h></STRONG>
58 <STRONG>int</STRONG> <STRONG>refresh(void);</STRONG>
59 <STRONG>int</STRONG> <STRONG>wrefresh(WINDOW</STRONG> <STRONG>*win);</STRONG>
60 <STRONG>int</STRONG> <STRONG>wnoutrefresh(WINDOW</STRONG> <STRONG>*win);</STRONG>
61 <STRONG>int</STRONG> <STRONG>doupdate(void);</STRONG>
62 <STRONG>int</STRONG> <STRONG>redrawwin(WINDOW</STRONG> <STRONG>*win);</STRONG>
63 <STRONG>int</STRONG> <STRONG>wredrawln(WINDOW</STRONG> <STRONG>*win,</STRONG> <STRONG>int</STRONG> <STRONG>beg_line,</STRONG> <STRONG>int</STRONG> <STRONG>num_lines);</STRONG>
67 <H2>DESCRIPTION</H2><PRE>
68 The <STRONG>refresh</STRONG> and <STRONG>wrefresh</STRONG> routines (or <STRONG>wnoutrefresh</STRONG> and
69 <STRONG>doupdate</STRONG>) must be called to get actual output to the ter-
70 minal, as other routines merely manipulate data struc-
71 tures. The routine <STRONG>wrefresh</STRONG> copies the named window to
72 the physical terminal screen, taking into account what is
73 already there to do optimizations. The <STRONG>refresh</STRONG> routine is
74 the same, using <STRONG>stdscr</STRONG> as the default window. Unless
75 <STRONG>leaveok</STRONG> has been enabled, the physical cursor of the ter-
76 minal is left at the location of the cursor for that win-
79 The <STRONG>wnoutrefresh</STRONG> and <STRONG>doupdate</STRONG> routines allow multiple
80 updates with more efficiency than <STRONG>wrefresh</STRONG> alone. In
81 addition to all the window structures, <STRONG>curses</STRONG> keeps two
82 data structures representing the terminal screen: a physi-
83 cal screen, describing what is actually on the screen, and
84 a virtual screen, describing what the programmer wants to
87 The routine <STRONG>wrefresh</STRONG> works by first calling <STRONG>wnoutrefresh</STRONG>,
88 which copies the named window to the virtual screen, and
89 then calling <STRONG>doupdate</STRONG>, which compares the virtual screen
90 to the physical screen and does the actual update. If the
91 programmer wishes to output several windows at once, a
92 series of calls to <STRONG>wrefresh</STRONG> results in alternating calls
93 to <STRONG>wnoutrefresh</STRONG> and <STRONG>doupdate</STRONG>, causing several bursts of
94 output to the screen. By first calling <STRONG>wnoutrefresh</STRONG> for
95 each window, it is then possible to call <STRONG>doupdate</STRONG> once,
96 resulting in only one burst of output, with fewer total
97 characters transmitted and less CPU time used. If the <EM>win</EM>
98 argument to <STRONG>wrefresh</STRONG> is the global variable <STRONG>curscr</STRONG>, the
99 screen is immediately cleared and repainted from scratch.
101 The phrase "copies the named window to the virtual screen"
102 above is ambiguous. What actually happens is that all
103 <EM>touched</EM> (changed) lines in the window are copied to the
104 virtual screen. This affects programs that use overlap-
105 ping windows; it means that if two windows overlap, you
106 can refresh them in either order and the overlap region
107 will be modified only when it is explicitly changed. (But
108 see the section on <STRONG>PORTABILITY</STRONG> below for a warning about
109 exploiting this behavior.)
111 The <STRONG>wredrawln</STRONG> routine indicates to <STRONG>curses</STRONG> that some screen
112 lines are corrupted and should be thrown away before any-
113 thing is written over them. It touches the indicated
114 lines (marking them changed). The routine <STRONG>redrawwin</STRONG>()
115 touches the entire window.
119 <H2>RETURN VALUE</H2><PRE>
120 Routines that return an integer return <STRONG>ERR</STRONG> upon failure,
121 and <STRONG>OK</STRONG> (SVr4 only specifies "an integer value other than
122 <STRONG>ERR</STRONG>") upon successful completion.
127 Note that <STRONG>refresh</STRONG> and <STRONG>redrawwin</STRONG> may be macros.
131 <H2>PORTABILITY</H2><PRE>
132 The XSI Curses standard, Issue 4 describes these func-
135 Whether <STRONG>wnoutrefresh()</STRONG> copies to the virtual screen the
136 entire contents of a window or just its changed portions
137 has never been well-documented in historic curses versions
138 (including SVr4). It might be unwise to rely on either
139 behavior in programs that might have to be linked with
140 other curses implementations. Instead, you can do an
141 explicit <STRONG>touchwin()</STRONG> before the <STRONG>wnoutrefresh()</STRONG> call to
142 guarantee an entire-contents copy anywhere.
146 <H2>SEE ALSO</H2><PRE>
147 <STRONG><A HREF="ncurses.3x.html">curses(3x)</A></STRONG>, <STRONG><A HREF="curs_outopts.3x.html">curs_outopts(3x)</A></STRONG>
151 <STRONG><A HREF="curs_refresh.3x.html">curs_refresh(3x)</A></STRONG>
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