Provided by: ncurses-doc_6.5+20250216-1_all 
NAME
newwin, delwin, mvwin, subwin, derwin, mvderwin, dupwin, wsyncup, syncok, wcursyncup, wsyncdown - create
and manipulate curses windows
SYNOPSIS
#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);
DESCRIPTION
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 created:
idcok idlok immedok keypad leaveok nodelay scrollok setscrreg syncok wbkgdset wbkgrndset and
wtimeout.
delwin
Calling delwin deletes the named window, freeing all memory associated with it (it does not actually
erase the window's screen image). 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. Moving
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, its ancestor, 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.
mvderwin
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 manually.
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.
RETURN VALUE
Functions that return integers return ERR upon failure and OK upon success.
Functions that return pointers return NULL on error.
ncurses defines several error conditions.
• delwin returns ERR if win is a null pointer, or if it is the parent of another window.
ncurses maintains a list of windows, and checks that the pointer passed to delwin is one that it
created, returning ERR if it was not.
• derwin returns ERR if orig is a null pointer, or if any of the ordinate or dimension arguments is
negative, or if the resulting window does not fit inside the parent window.
• dupwin returns ERR if win is a null pointer.
• mvderwin returns ERR if win is a null pointer, or if any part of the window would be placed off-
screen.
• mvwin returns ERR if win is a null pointer, if win is a pad, or if any part of the window would be
placed off-screen.
• newwin returns ERR if any of its arguments is negative.
• subwin returns ERR if orig is a null pointer, or if any of the ordinate or dimension arguments is
negative, or if the resulting window does not fit inside the parent window.
• syncok returns ERR if win is a null pointer.
Functions that return a window pointer fail if memory allocation for their data structures fails.
All of these functions fail if the screen has not been initialized; see initscr(3NCURSES) or
newterm(3NCURSES).
NOTES
syncok may be implemented as a macro.
Calling syncup on a window and making many small changes to it could degrade performance.
PORTABILITY
X/Open Curses Issue 4 describes these functions. It specifies no error conditions for delwin, derwin,
dupwin, newwin, mvderwin, or syncok.
For functions returning integers (except delwin), SVr4 describes a successful return value only as “an
integer value other than ERR”.
Regarding delwin, X/Open Curses states that
[t]he application must delete subwindows before deleting the main window.
If delwin is asked to delete a parent window, it can succeed only if the curses library keeps a list of
its 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 (xcurses) does not make even that
check, and will delete a parent window that still has subwindows. PDCurses also behaves this way.
ncurses 4.0 (1996) and later maintains a list of windows for each screen to ensure that a window has no
subwindows before allowing its deletion. NetBSD curses has followed suit since 2003.
SVr4 curses documentation is unclear about what wsyncup and wsyncdown actually do. It seems to imply
that they are supposed to touch only those lines that are affected by changes to a window's ancestors.
The description and behavior of these functions in ncurses is patterned on the X/Open Curses standard;
this approach may result in slower updates.
SEE ALSO
ncurses(3NCURSES), initscr(3NCURSES), refresh(3NCURSES), touch(3NCURSES), curses_variables(3NCURSES)