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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. 77 78 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 83 screen: 84 85 <STRONG>o</STRONG> a <EM>physical</EM> <EM>screen</EM>, describing what is actually on the screen, and 86 87 <STRONG>o</STRONG> a <EM>virtual</EM> <EM>screen</EM>, describing what the programmer wants to have on 88 the screen. 89 90 The routine <STRONG>wrefresh</STRONG> works by 91 92 <STRONG>o</STRONG> first calling <STRONG>wnoutrefresh</STRONG>, which copies the named window to the 93 <EM>virtual</EM> <EM>screen</EM>, and 94 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. 97 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. 104 105 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. 108 109 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.) 116 117 118</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. 123 124 125</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 128 completion. 129 130 X/Open Curses does not specify any error conditions. In this 131 implementation 132 133 <STRONG>wnoutrefresh</STRONG> 134 returns an error if the window pointer is null, or if the 135 window is really a pad. 136 137 <STRONG>wredrawln</STRONG> 138 returns an error if the associated call to <STRONG>touchln</STRONG> returns an 139 error. 140 141 142</PRE><H2><a name="h2-NOTES">NOTES</a></H2><PRE> 143 Note that <STRONG>refresh</STRONG> and <STRONG>redrawwin</STRONG> may be macros. 144 145 146</PRE><H2><a name="h2-PORTABILITY">PORTABILITY</a></H2><PRE> 147 X/Open Curses, Issue 4 describes these functions. 148 149 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 155 anywhere. 156 157 158</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> 160 161 162 163ncurses 6.5 2024-04-20 <STRONG><A HREF="curs_refresh.3x.html">curs_refresh(3x)</A></STRONG> 164</PRE> 165<div class="nav"> 166<ul> 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> 170<ul> 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> 174</ul> 175</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> 180</ul> 181</div> 182</BODY> 183</HTML> 184