https://invisible-island.net/ncurses/man/


curs_window 3x 2023-12-16 ncurses 6.4 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.   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

       Routines that return an integer return the integer ERR upon failure 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  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,
            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  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.


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
           parent 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
           allowing deletion.

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


BUGS

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

       System V's 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 language here, and behavior of 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 6.4                       2023-12-16                   curs_window(3x)