delwin(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
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).
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.
SEE ALSO
ncurses(3NCURSES), refresh(3NCURSES), touch(3NCURSES), curses_variables(3NCURSES) window(3NCURSES)
Opportunity
Personal Opportunity - Free software gives you access to billions of dollars of software at no cost. Use this software for your business, personal use or to develop a profitable skill. Access to source code provides access to a level of capabilities/information that companies protect though copyrights. Open source is a core component of the Internet and it is available to you. Leverage the billions of dollars in resources and capabilities to build a career, establish a business or change the world. The potential is endless for those who understand the opportunity.
Business Opportunity - Goldman Sachs, IBM and countless large corporations are leveraging open source to reduce costs, develop products and increase their bottom lines. Learn what these companies know about open source and how open source can give you the advantage.
Free Software
Free Software provides computer programs and capabilities at no cost but more importantly, it provides the freedom to run, edit, contribute to, and share the software. The importance of free software is a matter of access, not price. Software at no cost is a benefit but ownership rights to the software and source code is far more significant.
Free Office Software - The Libre Office suite provides top desktop productivity tools for free. This includes, a word processor, spreadsheet, presentation engine, drawing and flowcharting, database and math applications. Libre Office is available for Linux or Windows.
Free Books
The Free Books Library is a collection of thousands of the most popular public domain books in an online readable format. The collection includes great classical literature and more recent works where the U.S. copyright has expired. These books are yours to read and use without restrictions.
Source Code - Want to change a program or know how it works? Open Source provides the source code for its programs so that anyone can use, modify or learn how to write those programs themselves. Visit the GNU source code repositories to download the source.
Education
Study at Harvard, Stanford or MIT - Open edX provides free online courses from Harvard, MIT, Columbia, UC Berkeley and other top Universities. Hundreds of courses for almost all major subjects and course levels. Open edx also offers some paid courses and selected certifications.
Linux Manual Pages - A man or manual page is a form of software documentation found on Linux/Unix operating systems. Topics covered include computer programs (including library and system calls), formal standards and conventions, and even abstract concepts.
