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NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | NOTES | BUGS | PORTABILITY | SEE ALSO | COLOPHON |
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curs_window(3X) curs_window(3X)
newwin, delwin, mvwin, subwin, derwin, mvderwin, dupwin, wsyncup,
syncok, wcursyncup, wsyncdown - create curses windows
#include <curses.h>
WINDOW *newwin(
int nlines, int ncols,
int begin_y, int begin_x);
int delwin(WINDOW *win);
int mvwin(WINDOW *win, int y, int x);
WINDOW *subwin(WINDOW *orig,
int nlines, int ncols,
int begin_y, int begin_x);
WINDOW *derwin(WINDOW *orig,
int nlines, int ncols,
int begin_y, int begin_x);
int mvderwin(WINDOW *win, int par_y, int par_x);
WINDOW *dupwin(WINDOW *win);
void wsyncup(WINDOW *win);
int syncok(WINDOW *win, bool bf);
void wcursyncup(WINDOW *win);
void wsyncdown(WINDOW *win);
newwin
Calling newwin creates and returns a pointer to a new window with
the given number of lines and columns. The upper left-hand corner
of the window is at
line begin_y,
column begin_x
If either nlines or ncols is zero, they default to
LINES - begin_y and
COLS - begin_x.
A new full-screen window is created by calling newwin(0,0,0,0).
Regardless of the function used for creating a new window (e.g.,
newwin, subwin, derwin, newpad), rather than a duplicate (with
dupwin), all of the window modes are initialized to the default
values. These functions set window modes after a window is creat‐
ed:
idcok, idlok, immedok, keypad, leaveok, nodelay, scrollok,
setscrreg, syncok, wbkgdset, wbkgrndset, and wtimeout
delwin
Calling delwin deletes the named window, freeing all memory asso‐
ciated with it (it does not actually erase the window's screen im‐
age). Subwindows must be deleted before the main window can be
deleted.
mvwin
Calling mvwin moves the window so that the upper left-hand corner
is at position (x, y). If the move would cause the window to be
off the screen, it is an error and the window is not moved. Mov‐
ing subwindows is allowed, but should be avoided.
subwin
Calling subwin creates and returns a pointer to a new window with
the given number of lines, nlines, and columns, ncols. The window
is at position (begin_y, begin_x) on the screen. The subwindow
shares memory with the window orig, so that changes made to one
window will affect both windows. When using this routine, it is
necessary to call touchwin or touchline on orig before calling
wrefresh on the subwindow.
derwin
Calling derwin is the same as calling subwin, except that begin_y
and begin_x are relative to the origin of the window orig rather
than the screen. There is no difference between the subwindows
and the derived windows.
Calling mvderwin moves a derived window (or subwindow) inside its
parent window. The screen-relative parameters of the window are
not changed. This routine is used to display different parts of
the parent window at the same physical position on the screen.
dupwin
Calling dupwin creates an exact duplicate of the window win.
wsyncup
Calling wsyncup touches all locations in ancestors of win that are
changed in win. If syncok is called with second argument TRUE
then wsyncup is called automatically whenever there is a change in
the window.
wsyncdown
The wsyncdown routine touches each location in win that has been
touched in any of its ancestor windows. This routine is called by
wrefresh, so it should almost never be necessary to call it manu‐
ally.
wcursyncup
The routine wcursyncup updates the current cursor position of all
the ancestors of the window to reflect the current cursor position
of the window.
Routines that return an integer return the integer ERR upon fail‐
ure and OK (SVr4 only specifies "an integer value other than ERR")
upon successful completion.
Routines that return pointers return NULL on error.
X/Open defines no error conditions. In this implementation
delwin
returns an error if the window pointer is null, or if the
window is the parent of another window.
derwin
returns an error if the parent window pointer is null, or if
any of its ordinates or dimensions is negative, or if the re‐
sulting window does not fit inside the parent window.
dupwin
returns an error if the window pointer is null.
This implementation also maintains a list of windows, and
checks that the pointer passed to delwin is one that it cre‐
ated, returning an error if it was not..
mvderwin
returns an error if the window pointer is null, or if some
part of the window would be placed off-screen.
mvwin
returns an error if the window pointer is null, or if the
window is really a pad, or if some part of the window would
be placed off-screen.
newwin
will fail if either of its beginning ordinates is negative,
or if either the number of lines or columns is negative.
syncok
returns an error if the window pointer is null.
subwin
returns an error if the parent window pointer is null, or if
any of its ordinates or dimensions is negative, or if the re‐
sulting window does not fit inside the parent window.
The functions which return a window pointer may also fail if there
is insufficient memory for its data structures. Any of these
functions will fail if the screen has not been initialized, i.e.,
with initscr or newterm.
If many small changes are made to the window, the wsyncup option
could degrade performance.
Note that syncok may be a macro.
The subwindow functions (subwin, derwin, mvderwin, wsyncup, wsync‐
down, wcursyncup, syncok) are flaky, incompletely implemented, and
not well tested.
The System V curses documentation is very unclear about what wsyn‐
cup and wsyncdown actually do. It seems to imply that they are
only supposed to touch exactly those lines that are affected by
ancestor changes. The language here, and the behavior of the
curses implementation, is patterned on the XPG4 curses standard.
The weaker XPG4 spec may result in slower updates.
The XSI Curses standard, Issue 4 describes these functions.
X/Open Curses states regarding delwin:
• It must delete subwindows before deleting their parent.
• If delwin is asked to delete a parent window, it can only suc‐
ceed if the curses library keeps a list of the subwindows.
SVr4 curses kept a count of the number of subwindows rather
than a list. It simply returned ERR when asked to delete a
subwindow. Solaris X/Open curses does not even make that
check, and will delete a parent window which still has subwin‐
dows.
• Since release 4.0 (1996), ncurses maintains a list of windows
for each screen, to ensure that a window has no subwindows be‐
fore allowing deletion.
• NetBSD copied this feature of ncurses in 2003.
PDCurses follows the scheme used in Solaris X/Open curses.
curses(3X), curs_initscr(3X), curs_refresh(3X), curs_touch(3X),
curs_variables(3X)
This page is part of the ncurses (new curses) project. Informa‐
tion about the project can be found at
⟨https://www.gnu.org/software/ncurses/ncurses.html⟩. If you have a
bug report for this manual page, send it to
bug-ncurses-request@gnu.org. This page was obtained from the
project's upstream Git mirror of the CVS repository
⟨https://github.com/mirror/ncurses.git⟩ on 2025-02-02. (At that
time, the date of the most recent commit that was found in the
repository was 2023-03-12.) 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
curs_window(3X)
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HTML rendering created 2025-02-02 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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