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Under GNU General Public License
2012-05-26 07:47 @38.107.179.240 Crawled by CCBot/1.0 (+http://www.commoncrawl.org/bot.html)
refresh(3NCURSES) refresh(3NCURSES)
NAME
doupdate, redrawwin, refresh, wnoutrefresh, wredrawln, wrefresh - refresh curses windows
and lines
SYNOPSIS
#include <curses.h>
int refresh(void);
int wrefresh(WINDOW *win);
int wnoutrefresh(WINDOW *win);
int doupdate(void);
int redrawwin(WINDOW *win);
int wredrawln(WINDOW *win, int beg_line, int num_lines);
DESCRIPTION
The refresh and wrefresh routines (or wnoutrefresh and doupdate) must be called to get ac-
tual output to the terminal, as other routines merely manipulate data structures. The
routine wrefresh copies the named window to the physical terminal screen, taking into ac-
count what is already there to do optimizations. The refresh routine is the same, using
stdscr as the default window. Unless leaveok has been enabled, the physical cursor of the
terminal is left at the location of the cursor for that window.
The wnoutrefresh and doupdate routines allow multiple updates with more efficiency than
wrefresh alone. In addition to all the window structures, curses keeps two data struc-
tures 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 wrefresh works by first calling wnoutrefresh, which copies the named window to
the virtual screen, and then calling doupdate, 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 series of calls to wrefresh results in alternating calls to wnoutre-
fresh and doupdate, causing several bursts of output to the screen. By first calling
wnoutrefresh for each window, it is then possible to call doupdate once, resulting in only
one burst of output, with fewer total characters transmitted and less CPU time used. If
the win argument to wrefresh is the global variable curscr, the screen is immediately
cleared and repainted from scratch.
The phrase "copies the named window to the virtual screen" above is ambiguous. What actu-
ally happens is that all touched (changed) lines in the window are copied to the virtual
screen. This affects programs that use overlapping 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 PORTABILITY below for a warning
about exploiting this behavior.)
The wredrawln routine indicates to curses that some screen lines are corrupted and should
be thrown away before anything is written over them. It touches the indicated lines
(marking them changed). The routine redrawwin() touches the entire window.
RETURN VALUE
Routines that return an integer return ERR upon failure, and OK (SVr4 only specifies "an
integer value other than ERR") upon successful completion.
X/Open does not define any error conditions. In this implementation
wnoutrefresh
returns an error if the window pointer is null, or if the window is really a
pad.
wredrawln
returns an error if the associated call to touchln returns an error.
NOTES
Note that refresh and redrawwin may be macros.
PORTABILITY
The XSI Curses standard, Issue 4 describes these functions.
Whether wnoutrefresh() copies to the virtual screen the entire contents of a window or
just its changed portions has never been well-documented in historic curses versions (in-
cluding SVr4). It might be unwise to rely on either behavior in programs that might have
to be linked with other curses implementations. Instead, you can do an explicit touch-
win() before the wnoutrefresh() call to guarantee an entire-contents copy anywhere.
SEE ALSO
ncurses(3NCURSES), outopts(3NCURSES)
refresh(3NCURSES)
Generated by $Id: phpMan.php,v 4.49 2006/02/26 13:18:18 chedong Exp $ Author: Che Dong
On Apache
Under GNU General Public License
2012-05-26 07:47 @38.107.179.240 Crawled by CCBot/1.0 (+http://www.commoncrawl.org/bot.html)