window(3NCURSES)window(3NCURSES)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
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).
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.
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.
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. (This position is relative
to the screen, and not to the window orig.) The window is made in the
middle of the window orig, so that changes made to one window will af‐
fect both windows. The subwindow shares memory with the window orig.
When using this routine, it is necessary to call touchwin or touchline
on orig before calling wrefresh on the subwindow.
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.
Calling dupwin creates an exact duplicate of the window win.
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.
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.
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.
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.
syncok
returns an error if the window pointer is null.
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.
SEE ALSOncurses(3NCURSES), refresh(3NCURSES), touch(3NCURSES)window(3NCURSES)
