+.\"***************************************************************************
+.\" Copyright 2020 Thomas E. Dickey *
+.\" Copyright 1998-2013,2015 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_overlay.3x,v 1.19 2020/02/02 23:34:34 tom Exp $
.TH curs_overlay 3X ""
+.na
+.hy 0
.SH NAME
-\fBoverlay\fR, \fBoverwrite\fR, \fBcopywin\fR - overlay and
-manipulate overlapped \fBcurses\fR windows
+\fBoverlay\fR,
+\fBoverwrite\fR,
+\fBcopywin\fR \- overlay and manipulate overlapped \fBcurses\fR windows
+.ad
+.hy
.SH SYNOPSIS
\fB#include <curses.h>\fR
-
-\fBint overlay(const WINDOW *srcwin, WINDOW *dstwin);\fR
+.sp
+\fBint overlay(const WINDOW *\fP\fIsrcwin\fP\fB, WINDOW *\fP\fIdstwin\fP\fB);\fR
.br
-\fBint overwrite(const WINDOW *srcwin, WINDOW *dstwin);\fR
+\fBint overwrite(const WINDOW *\fP\fIsrcwin\fP\fB, WINDOW *\fP\fIdstwin\fP\fB);\fR
.br
-\fBint copywin(WINDOW *srcwin, WINDOW *dstwin, int sminrow,
- int smincol, int dminrow, int dmincol, int dmaxrow,
- int dmaxcol, int overlay);\fR
+\fBint copywin(const WINDOW *\fP\fIsrcwin\fP\fB, WINDOW *\fP\fIdstwin\fP\fB, int \fP\fIsminrow\fP\fB,\fR
+ \fBint \fP\fIsmincol\fP\fB, int \fP\fIdminrow\fP\fB, int \fP\fIdmincol\fP\fB, int \fP\fIdmaxrow\fP\fB,\fR
+ \fBint \fP\fIdmaxcol\fP\fB, int \fP\fIoverlay\fP\fB);\fR
.SH DESCRIPTION
+.SS overlay, overwrite
The \fBoverlay\fR and \fBoverwrite\fR routines overlay \fIsrcwin\fR on
-top of \fIdstwin\fR. \fIscrwin\fR and \fIdstwin\fR are not required
-to be the same size; only text where the two windows overlap is
-copied. The difference is that \fBoverlay\fR is non-destructive
+top of \fIdstwin\fR.
+\fIscrwin\fR and \fIdstwin\fR are not required
+to be the same size; only text where the two windows overlap is copied.
+The difference is that \fBoverlay\fR is non-destructive
(blanks are not copied) whereas \fBoverwrite\fR is destructive.
-
+.SS copywin
+.PP
The \fBcopywin\fR routine provides a finer granularity of control over the
-\fBoverlay\fR and \fBoverwrite\fR routines. Like in the \fBprefresh\fR
-routine, a rectangle is specified in the destination window, (\fIdminrow\fR,
+\fBoverlay\fR and \fBoverwrite\fR routines.
+As in the \fBprefresh\fR routine,
+a rectangle is specified in the destination window, (\fIdminrow\fR,
\fIdmincol\fR) and (\fIdmaxrow\fR, \fIdmaxcol\fR), and the upper-left-corner
-coordinates of the source window, (\fIsminrow\fR, \fIsmincol\fR). If the
-argument \fIoverlay\fR is \fBtrue\fR, then copying is non-destructive, as in
-\fBoverlay\fR.
+coordinates of the source window, (\fIsminrow\fR, \fIsmincol\fR).
+If the argument \fIoverlay\fR is \fBtrue\fR,
+then copying is non-destructive,
+as in \fBoverlay\fR.
.SH RETURN VALUE
Routines that return an integer return \fBERR\fR upon failure, and \fBOK\fR
(SVr4 only specifies "an integer value other than \fBERR\fR") upon successful
completion.
+.PP
+X/Open defines no error conditions.
+In this implementation,
+\fBcopywin\fP,
+\fBoverlay\fP and \fBoverwrite\fP return an error
+if either of the window pointers are null, or
+if some part of the window would be placed off-screen.
.SH NOTES
Note that \fBoverlay\fR and \fBoverwrite\fR may be macros.
.SH PORTABILITY
The XSI Curses standard, Issue 4 describes these functions (adding the const
-qualifiers). It further specifies their behavior in the presence of characters
-with multi-byte renditions (not yet supported in this implementation).
+qualifiers).
+It further specifies their behavior in the presence of characters
+with multibyte renditions (not yet supported in this implementation).
.SH SEE ALSO
\fBcurses\fR(3X), \fBcurs_pad\fR(3X), \fBcurs_refresh\fR(3X)
-.\"#
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