curs_refresh(3X) SDK R4.11 curs_refresh(3X)
NAME
curs_refresh: refresh, wrefresh, wnoutrefresh, doupdate, redrawwin,
wredrawln - 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 any output on the terminal, as other routines merely
manipulate data structures. The routine wrefresh copies the named
window to the physical terminal screen, taking into account what is
already there in order 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 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 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 wnoutrefresh 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 redrawwin routine indicates to curses that some screen lines are
corrupted and should be thrown away before anything is written over
them. These routines could be used for programs such as editors,
which want a command to redraw some part of the screen or the entire
screen. The routine redrawln is preferred over redrawwin where a
noisy communication line exists and redrawing the entire window could
be subject to even more communication noise. Just redrawing several
lines offers the possibility that they would show up unblemished.
RETURN VALUE
All routines return the integer ERR upon failure and an integer value
other than ERR upon successful completion.
NOTES
The header file <curses.h> automatically includes the header files
<stdio.h> and <unctrl.h>.
Note that refresh and redrawwin may be macros.
SEE ALSO
curses(3X), curs_outopts(3X).
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