# curs_window 3x 2025-08-23 ncurses 6.6 Library calls

    curs_window(3x)                  Library calls                 curs_window(3x)

## 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.  The
           following functions set a window's modes after it is created:

                  idcok, idlok,  immedok,  keypad,  leaveok,  nodelay,  notimeout,
                  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 a null pointer on failure.

           ncurses defines several error conditions.

           o   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.

           o   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.

           o   dupwin returns ERR if win is a null pointer.

           o   mvderwin  returns  ERR  if win is a null pointer, or if any part of
               the window would be placed off-screen.

           o   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.

           o   newwin returns ERR if any of its arguments is negative.

           o   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.

           o   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(3x) or newterm(3x).

## 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

           curses(3x),   curs_initscr(3x),    curs_refresh(3x),    curs_touch(3x),
           curs_variables(3x)

    ncurses 6.6                       2025-08-23                   curs_window(3x)