Ubuntu Manpage: newwin, delwin, mvwin, subwin, derwin, mvderwin, dupwin, wsyncup, syncok, wcursyncup,

Provided by: ncurses-doc_6.4+20230625-2_all

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). 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, 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.

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.

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 supposed to touch exactly  those  lines
       that  are affected by ancestor changes.  The language here, and the behavior of the curses
       implementation, 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:

       •   It must delete subwindows before deleting their parent.

       •   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.

       •   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.

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