# curs_window 3x

    curs_window(3x)                                                curs_window(3x)

## NAME

           newwin, delwin, mvwin, subwin, derwin, mvderwin, dupwin, wsyncup,
           syncok, wcursyncup, wsyncdown - create 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).  Sub-
           windows 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, so that changes made to one  window  will  affect
           both  windows.  When using this routine, it is necessary to call touch-
           win 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 par-
           ent 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  win-
           dow.

### wsyncdown

           The  wsyncdown  routine  touches  each  location  in  win that has been
           touched in any of its ancestor windows.  This routine is called by wre-
           fresh, 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

           Routines that return an integer return the integer ERR upon failure and
           OK (SVr4 only specifies "an integer value other than  ERR")  upon  suc-
           cessful 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 resulting
                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 created, return-
                ing 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 resulting
                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.

## NOTES

           If  many small changes are made to the window, the wsyncup option could
           degrade performance.

           Note that syncok may be a macro.

## BUGS

           The subwindow functions (subwin, derwin, mvderwin, wsyncup,  wsyncdown,
           wcursyncup,  syncok)  are flaky, incompletely implemented, and not well
           tested.

           The System V curses documentation is very unclear  about  what  wsyncup
           and  wsyncdown  actually do.  It seems to imply that they are only sup-
           posed to touch exactly  those  lines  that  are  affected  by  ancestor
           changes.  The language here, and the behavior of the curses implementa-
           tion, is patterned on the XPG4 curses standard.  The weaker  XPG4  spec
           may result in slower updates.

## PORTABILITY

           The XSI Curses standard, Issue 4 describes these functions.

           X/Open Curses states regarding delwin:

           o   It must delete subwindows before deleting their parent.

           o   If  delwin  is asked to delete a parent window, it can only succeed
               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 par-
               ent window which still has subwindows.

           o   Since release 4.0 (1996), ncurses maintains a list of  windows  for
               each  screen,  to ensure that a window has no subwindows before al-
               lowing deletion.

           o   NetBSD copied this feature of ncurses in 2003.
               PDCurses follows the scheme used in Solaris X/Open curses.

## SEE ALSO

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

                                                                   curs_window(3x)