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

Provided by: ncurses-doc_6.4+20240113-1ubuntu2_all

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:

       •   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.

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.