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NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | NOTES | PORTABILITY | SEE ALSO | COLOPHON |
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curs_refresh(3X) Library calls curs_refresh(3X)
doupdate, redrawwin, refresh, wnoutrefresh, wredrawln, wrefresh -
refresh curses windows or lines thereupon
#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);
refresh, wrefresh
The refresh and wrefresh routines (or wnoutrefresh and doupdate)
must be called to get actual output to the terminal, as other
routines merely manipulate data structures. The routine wrefresh
copies the named window to the physical screen, taking into
account what is already there to do optimizations. The refresh
routine is the same, using stdscr as the default window. Unless
leaveok(3X) has been enabled, the physical cursor of the terminal
is left at the location of the cursor for that window.
wnoutrefresh, doupdate
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 physical screen (i.e., 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 actually 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.)
wredrawln, redrawwin
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.
These routines return the integer ERR upon failure and OK
In this implementation
wnoutrefresh
returns ERR if the window pointer is null, or if the
window is really a pad.
wredrawln
return ERR if the associated call to touchln returns ERR.
refresh and redrawwin may be implemented as macros.
X/Open Curses Issue 4 describes these functions. It specifies no
error conditions for them.
SVr4 describes a successful return value only as “an integer value
other than ERR”.
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 (including 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 touchwin before the wnoutrefresh call to
guarantee an entire-contents copy anywhere.
curses(3X), curs_outopts(3X), curs_variables(3X)
This page is part of the ncurses (new curses) project.
Information about the project can be found at
⟨https://invisible-island.net/ncurses/ncurses.html⟩. If you have a
bug report for this manual page, send it to bug-ncurses@gnu.org.
This page was obtained from the tarball ncurses-6.6.tar.gz fetched
from ⟨https://ftp.gnu.org/gnu/ncurses/⟩ on 2026-01-16. If you
discover any rendering problems in this HTML version of the page,
or you believe there is a better or more up-to-date source for the
page, or you have corrections or improvements to the information
in this COLOPHON (which is not part of the original manual page),
send a mail to man-pages@man7.org
ncurses @NCURSES_MAJOR@.@NCU... 2025-01-18 curs_refresh(3X)
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HTML rendering created 2026-01-16 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
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