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). Subwindows 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 affect 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 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.

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 window.

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.

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.

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 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.

SEE ALSO

ncurses(3NCURSES), refresh(3NCURSES), touch(3NCURSES)

window(3NCURSES)