CURS_REFRESH(3CURSES) Curses Library Functions CURS_REFRESH(3CURSES)
NAME
curs_refresh, refresh, wrefresh, wnoutrefresh, doupdate, redrawwin,
wredrawln - refresh curses windows and lines
SYNOPSIS
cc [
flag ... ]
file ...
-lcurses [
library ... ]
#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 VALUES
All routines return the integer
ERR upon failure and an integer value
other than
ERR upon successful completion.
ATTRIBUTES
See
attributes(7) for descriptions of the following attributes:
+---------------+-----------------+
|ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+---------------+-----------------+
|MT-Level | Unsafe |
+---------------+-----------------+
SEE ALSO
curs_outopts(3CURSES),
curses(3CURSES),
attributes(7)NOTES
The header <
curses.h> automatically includes the headers <
stdio.h>
and <
unctrl.h>.
Note that
refresh() and
redrawwin() may be macros.
December 31, 1996 CURS_REFRESH(3CURSES)
