-</PRE>
-<H2>DESCRIPTION</H2><PRE>
- The <STRONG>refresh</STRONG> and <STRONG>wrefresh</STRONG> routines (or <STRONG>wnoutrefresh</STRONG> and
- <STRONG>doupdate</STRONG>) must be called to get actual output to the ter-
- minal, as other routines merely manipulate data struc-
- tures. The routine <STRONG>wrefresh</STRONG> copies the named window to
- the physical terminal screen, taking into account what is
- already there to do optimizations. The <STRONG>refresh</STRONG> routine is
- the same, using <STRONG>stdscr</STRONG> as the default window. Unless
- <STRONG>leaveok</STRONG> has been enabled, the physical cursor of the ter-
- minal is left at the location of the cursor for that win-
- dow.
-
- The <STRONG>wnoutrefresh</STRONG> and <STRONG>doupdate</STRONG> routines allow multiple up-
- dates with more efficiency than <STRONG>wrefresh</STRONG> alone. In addi-
- tion to all the window structures, <STRONG>curses</STRONG> keeps two data
- structures representing the terminal screen: a physical
- screen, describing what is actually on the screen, and a
- virtual screen, describing what the programmer wants to
- have on the screen.
-
- The routine <STRONG>wrefresh</STRONG> works by first calling <STRONG>wnoutrefresh</STRONG>,
- which copies the named window to the virtual screen, and
- then calling <STRONG>doupdate</STRONG>, which compares the virtual screen
- to the physical screen and does the actual update. If the
- programmer wishes to output several windows at once, a se-
- ries of calls to <STRONG>wrefresh</STRONG> results in alternating calls to
- <STRONG>wnoutrefresh</STRONG> and <STRONG>doupdate</STRONG>, causing several bursts of out-
- put to the screen. By first calling <STRONG>wnoutrefresh</STRONG> for each
- window, it is then possible to call <STRONG>doupdate</STRONG> once, result-
- ing in only one burst of output, with fewer total charac-
- ters transmitted and less CPU time used. If the <EM>win</EM> argu-
- ment to <STRONG>wrefresh</STRONG> is the global variable <STRONG>curscr</STRONG>, the screen
- is immediately cleared and repainted from scratch.
-
- The phrase "copies the named window to the virtual screen"
- above is ambiguous. What actually happens is that all
- <EM>touched</EM> (changed) lines in the window are copied to the
- virtual screen. This affects programs that use overlap-
- ping windows; it means that if two windows overlap, you
- can refresh them in either order and the overlap region
- will be modified only when it is explicitly changed. (But
- see the section on <STRONG>PORTABILITY</STRONG> below for a warning about
- exploiting this behavior.)
-
- The <STRONG>wredrawln</STRONG> routine indicates to <STRONG>curses</STRONG> that some screen
- lines are corrupted and should be thrown away before any-
- thing is written over them. It touches the indicated
- lines (marking them changed). The routine <STRONG>redrawwin</STRONG>()
- touches the entire window.
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