# curs_window 3x 2025-08-16 ncurses 6.5 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 NULL on error.

           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 6.5                       2025-08-16                   curs_window(3x)