path: root/man/curs_window.3x

.\"***************************************************************************
.\" Copyright 2020-2024,2025 Thomas E. Dickey                                *
.\" Copyright 1998-2015,2016 Free Software Foundation, Inc.                  *
.\"                                                                          *
.\" Permission is hereby granted, free of charge, to any person obtaining a  *
.\" copy of this software and associated documentation files (the            *
.\" "Software"), to deal in the Software without restriction, including      *
.\" without limitation the rights to use, copy, modify, merge, publish,      *
.\" distribute, distribute with modifications, sublicense, and/or sell       *
.\" copies of the Software, and to permit persons to whom the Software is    *
.\" furnished to do so, subject to the following conditions:                 *
.\"                                                                          *
.\" The above copyright notice and this permission notice shall be included  *
.\" in all copies or substantial portions of the Software.                   *
.\"                                                                          *
.\" THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS  *
.\" OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF               *
.\" MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.   *
.\" IN NO EVENT SHALL THE ABOVE COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,   *
.\" DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR    *
.\" OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR    *
.\" THE USE OR OTHER DEALINGS IN THE SOFTWARE.                               *
.\"                                                                          *
.\" Except as contained in this notice, the name(s) of the above copyright   *
.\" holders shall not be used in advertising or otherwise to promote the     *
.\" sale, use or other dealings in this Software without prior written       *
.\" authorization.                                                           *
.\"***************************************************************************
.\"
.\" $Id: curs_window.3x,v 1.71 2025/08/23 22:50:00 tom Exp $
.TH curs_window 3X 2025-08-23 "ncurses @NCURSES_MAJOR@.@NCURSES_MINOR@" "Library calls"
.ie \n(.g \{\
.ds `` \(lq
.ds '' \(rq
.\}
.el \{\
.ie t .ds `` ``
.el   .ds `` ""
.ie t .ds '' ''
.el   .ds '' ""
.\}
.
.de bP
.ie n  .IP \(bu 4
.el    .IP \(bu 2
..
.SH NAME
\fB\%newwin\fP,
\fB\%delwin\fP,
\fB\%mvwin\fP,
\fB\%subwin\fP,
\fB\%derwin\fP,
\fB\%mvderwin\fP,
\fB\%dupwin\fP,
\fB\%wsyncup\fP,
\fB\%syncok\fP,
\fB\%wcursyncup\fP,
\fB\%wsyncdown\fP \-
create and manipulate \fIcurses\fR windows
.SH SYNOPSIS
.nf
\fB#include <curses.h>
.PP
\fBWINDOW * newwin(\fR
	\fBint \fInlines\fP, int \fIncols\fP,
	\fBint \fIbegin_y\fP, int \fIbegin_x\fP);
\fBint delwin(WINDOW * \fIwin\fP);
\fBint mvwin(WINDOW * \fIwin\fP, int \fIy\fP, int \fIx\fP);
\fBWINDOW * subwin(WINDOW * \fIorig\fP,
	\fBint \fInlines\fP, int \fIncols\fP,
	\fBint \fIbegin_y\fP, int \fIbegin_x\fP);
\fBWINDOW * derwin(WINDOW * \fIorig\fP,
	\fBint \fInlines\fP, int \fIncols\fP,
	\fBint \fIbegin_y\fP, int \fIbegin_x\fP);
\fBint mvderwin(WINDOW * \fIwin\fP, int \fIpar_y\fP, int \fIpar_x\fP);
\fBWINDOW * dupwin(WINDOW * \fIwin\fP);
\fBvoid wsyncup(WINDOW * \fIwin\fP);
\fBint syncok(WINDOW * \fIwin\fP, bool \fIbf\fP);
\fBvoid wcursyncup(WINDOW * \fIwin\fP);
\fBvoid wsyncdown(WINDOW * \fIwin\fP);
.fi
.SH DESCRIPTION
.SS newwin
Calling \fBnewwin\fP 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
.RS
line \fIbegin\fR_\fIy\fP,
.br
column \fIbegin\fR_\fIx\fP
.RE
.PP
If either
\fInlines\fP or \fIncols\fP is zero, they default to
.RS
\fBLINES \-\fP \fIbegin\fR_\fIy\fP and
.br
\fBCOLS \-\fP \fIbegin\fR_\fIx\fP.
.RE
.PP
A new full-screen window is created by calling \fBnewwin(0,0,0,0)\fP.
.PP
Regardless of the function used for creating a new window
(e.g., \fBnewwin\fP, \fBsubwin\fP, \fBderwin\fP, \fBnewpad\fP),
rather than a duplicate (with \fBdupwin\fP),
all of the window modes are initialized to the default values.
The following functions set a window's modes after it is created:
.RS
.PP
.BR \%idcok ","
.BR \%idlok ","
.BR \%immedok ","
.BR \%keypad ","
.BR \%leaveok ","
.BR \%nodelay ","
.BR \%notimeout ","
.BR \%scrollok ","
.BR \%setscrreg ","
.BR \%syncok ","
.BR \%wbkgdset ","
.BR \%wbkgrndset ","
and
.BR \%wtimeout "."
.RE
.SS delwin
Calling \fBdelwin\fP 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.
.SS mvwin
Calling \fBmvwin\fP moves the window so that the upper left-hand
corner is at position (\fIx\fP, \fIy\fP).
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.
.SS subwin
Calling \fBsubwin\fP creates and returns a pointer to a new window
with the given number of lines, \fInlines\fP, and columns, \fIncols\fP.
The window is at position (\fIbegin\fR_\fIy\fP,
\fIbegin\fR_\fIx\fP) on the screen.
The subwindow shares memory with the window \fIorig\fP,
its \fIancestor\fP,
so that changes made to one window
will affect both windows.
When using this routine, it is necessary to call
\fBtouchwin\fP or \fBtouchline\fP on \fIorig\fP before calling
\fBwrefresh\fP on the subwindow.
.SS derwin
Calling \fBderwin\fP is the same as calling \fBsubwin,\fP except that
\fIbegin\fR_\fIy\fP and \fIbegin\fR_\fIx\fP are relative to the origin
of the window \fIorig\fP rather than the screen.
There is no difference between the subwindows and the derived windows.
.SS mvderwin
Calling \fBmvderwin\fP 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.
.SS dupwin
Calling \fBdupwin\fP creates an exact duplicate of the window \fIwin\fP.
.SS wsyncup
Calling \fBwsyncup\fP touches all locations in ancestors of \fIwin\fP that are
changed in \fIwin\fP.
If \fBsyncok\fP is called with second argument
\fBTRUE\fP then \fBwsyncup\fP is called automatically whenever there is a
change in the window.
.SS wsyncdown
The \fBwsyncdown\fP routine touches each location in \fIwin\fP that has been
touched in any of its ancestor windows.
This routine is called by
\fBwrefresh\fP, so it should almost never be necessary to call it manually.
.SS wcursyncup
The routine \fBwcursyncup\fP updates the current cursor position of all the
ancestors of the window to reflect the current cursor position of the
window.
.SH RETURN VALUE
Functions that return integers return
.B ERR
upon failure and
.B OK
upon success.
.PP
Functions that return pointers return a null pointer on failure.
.PP
.I \%ncurses
defines several error conditions.
.bP
.B \%delwin
returns
.B ERR
if
.I win
is a null pointer,
or if it is the parent of another window.
.IP
.I \%ncurses
maintains a list of windows,
and checks that the pointer passed to
.B \%delwin
is one that it created,
returning
.B ERR
if it was not.
.bP
.B \%derwin
returns
.B ERR
if
.I orig
is a null pointer,
or if any of the ordinate or dimension arguments is negative,
or if the resulting window does not fit inside the parent window.
.bP
.B \%dupwin
returns
.B ERR
if
.I win
is a null pointer.
.bP
.B \%mvderwin
returns
.B ERR
if
.I win
is a null pointer,
or if any part of the window would be placed off-screen.
.bP
.B \%mvwin
returns
.B ERR
if
.I win
is a null pointer,
if
.I win
is a pad,
or if any part of the window would be placed off-screen.
.bP
.B \%newwin
returns
.B ERR
if any of its arguments is negative.
.bP
.B \%subwin
returns
.B ERR
if
.I orig
is a null pointer,
or if any of the ordinate or dimension arguments is negative,
or if the resulting window does not fit inside the parent window.
.bP
.B \%syncok
returns
.B ERR
if
.I win
is a null pointer.
.PP
Functions that return a window pointer fail if memory allocation
for their data structures fails.
.PP
All of these functions fail if the screen has not been initialized;
see \fBinitscr\fP(3X) or \fBnewterm\fP(3X).
.SH NOTES
.B \%syncok
may be implemented as a macro.
.PP
Calling
.B \%syncup
on a window and making many small changes to it
could degrade performance.
.SH PORTABILITY
X/Open Curses Issue\ 4 describes these functions.
It specifies no error conditions for
.IR \%delwin ","
.IR \%derwin ","
.IR \%dupwin ","
.IR \%newwin ","
.IR \%mvderwin ","
or
.IR \%syncok "."
.PP
For functions returning integers
(except
.IR \%delwin "),"
SVr4 describes a successful return value only as
\*(``an integer value other than
.IR ERR \*(''. \" Courier roman in source; SVID 4, vol. 3, p. 544
.PP
Regarding
.IR \%delwin ","
X/Open Curses states that
.RS
.PP
[t]he application must delete subwindows before deleting the main
window.
.RE
.PP
If
.I \%delwin
is asked to delete a parent window,
it can succeed only if the
.I curses
library keeps a list of its subwindows.
SVr4
.I curses
kept a count of the number of subwindows rather than a list.
It simply returned
.B ERR
when asked to delete a subwindow.
Solaris X/Open
.I curses
.RI \%( xcurses )
does not make even that check,
and will delete a parent window that still has subwindows.
.I \%PDCurses
also behaves this way.
.PP
.I \%ncurses
4.0 (1996) and later maintains a list of windows for each screen
to ensure that a window has no subwindows before allowing its deletion.
NetBSD
.I curses
has followed suit since 2003.
.PP
SVr4
.I curses
documentation is unclear about what
.I \%wsyncup
and
.I \%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 description and behavior of these functions in
.I \%ncurses
is patterned on the X/Open Curses standard;
this approach may result in slower updates.
.SH SEE ALSO
\fB\%curses\fP(3X),
\fB\%curs_initscr\fP(3X),
\fB\%curs_refresh\fP(3X),
\fB\%curs_touch\fP(3X),
\fB\%curs_variables\fP(3X)