.\"***************************************************************************
-.\" Copyright (c) 1998 Free Software Foundation, Inc. *
+.\" Copyright 2018,2020 Thomas E. Dickey *
+.\" Copyright 1998-2015,2017 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 *
.\" authorization. *
.\"***************************************************************************
.\"
-.\" $Id: curs_pad.3x,v 1.8 1998/12/26 20:09:03 tom Exp $
+.\" $Id: curs_pad.3x,v 1.26 2020/02/02 23:34:34 tom Exp $
+.de bP
+.ie n .IP \(bu 4
+.el .IP \(bu 2
+..
.TH curs_pad 3X ""
+.na
+.hy 0
.SH NAME
-\fBnewpad\fR, \fBsubpad\fR, \fBprefresh\fR,
-\fBpnoutrefresh\fR, \fBpechochar\fR - create and display \fBcurses\fR
-pads
+\fBnewpad\fR,
+\fBsubpad\fR,
+\fBprefresh\fR,
+\fBpnoutrefresh\fR,
+\fBpechochar\fR,
+\fBpecho_wchar\fR \- create and display \fBcurses\fR pads
+.ad
+.hy
.SH SYNOPSIS
\fB#include <curses.h>\fR
-
-\fBWINDOW *newpad(int nlines, int ncols);\fR
+.sp
+\fBWINDOW *newpad(int \fP\fInlines\fP\fB, int \fP\fIncols\fP\fB);\fR
.br
-\fBWINDOW *subpad(WINDOW *orig, int nlines, int ncols,\fR
- \fBint begin_y, int begin_x);\fR
+\fBWINDOW *subpad(WINDOW *\fP\fIorig\fP\fB, int \fP\fInlines\fP\fB, int \fP\fIncols\fP\fB,\fR
+ \fBint \fP\fIbegin_y\fP\fB, int \fP\fIbegin_x\fP\fB);\fR
.br
-\fBint prefresh(WINDOW *pad, int pminrow, int pmincol,\fR
- \fBint sminrow, int smincol, int smaxrow, int smaxcol);\fR
+\fBint prefresh(WINDOW *\fP\fIpad\fP\fB, int \fP\fIpminrow\fP\fB, int \fP\fIpmincol\fP\fB,\fR
+ \fBint \fP\fIsminrow\fP\fB, int \fP\fIsmincol\fP\fB, int \fP\fIsmaxrow\fP\fB, int \fP\fIsmaxcol\fP\fB);\fR
.br
-\fBint pnoutrefresh(WINDOW *pad, int pminrow, int pmincol,\fR
- \fBint sminrow, int smincol, int smaxrow, int smaxcol);\fR
+\fBint pnoutrefresh(WINDOW *\fP\fIpad\fP\fB, int \fP\fIpminrow\fP\fB, int \fP\fIpmincol\fP\fB,\fR
+ \fBint \fP\fIsminrow\fP\fB, int \fP\fIsmincol\fP\fB, int \fP\fIsmaxrow\fP\fB, int \fP\fIsmaxcol\fP\fB);\fR
.br
-\fBint pechochar(WINDOW *pad, chtype ch);\fR
+\fBint pechochar(WINDOW *\fP\fIpad\fP\fB, chtype \fP\fIch\fP\fB);\fR
+.br
+\fBint pecho_wchar(WINDOW *\fP\fIpad\fP\fB, const cchar_t *\fP\fIwch\fP\fB);\fR
.SH DESCRIPTION
+.SS newpad
The \fBnewpad\fR routine creates and returns a pointer to a new pad data
structure with the given number of lines, \fInlines\fR, and columns,
-\fIncols\fR. A pad is like a window, except that it is not restricted by the
+\fIncols\fR.
+A pad is like a window, except that it is not restricted by the
screen size, and is not necessarily associated with a particular part of the
-screen. Pads can be used when a large window is needed, and only a part of the
-window will be on the screen at one time. Automatic refreshes of pads
-(\fIe\fR.\fIg\fR., from scrolling or echoing of input) do not occur. It is not
+screen.
+Pads can be used when a large window is needed, and only a part of the
+window will be on the screen at one time.
+Automatic refreshes of pads
+(e.g., from scrolling or echoing of input) do not occur.
+.PP
+It is not
legal to call \fBwrefresh\fR with a \fIpad\fR as an argument; the routines
-\fBprefresh\fR or \fBpnoutrefresh\fR should be called instead. Note that these
+\fBprefresh\fR or \fBpnoutrefresh\fR should be called instead.
+Note that these
routines require additional parameters to specify the part of the pad to be
displayed and the location on the screen to be used for the display.
-
+.SS subpad
+.PP
The \fBsubpad\fR routine creates and returns a pointer to a subwindow within a
pad with the given number of lines, \fInlines\fR, and columns, \fIncols\fR.
Unlike \fBsubwin\fR, which uses screen coordinates, the window is at position
-(\fIbegin\fR_\fIx\fR\fB,\fR \fIbegin\fR_\fIy\fR) on the pad. The window is
+(\fIbegin\fR_\fIx\fR\fB,\fR \fIbegin\fR_\fIy\fR) on the pad.
+The window is
made in the middle of the window \fIorig\fR, so that changes made to one window
-affect both windows. During the use of this routine, it will often be
+affect both windows.
+During the use of this routine, it will often be
necessary to call \fBtouchwin\fR or \fBtouchline\fR on \fIorig\fR before
calling \fBprefresh\fR.
-
+.SS prefresh, pnoutrefresh
+.PP
The \fBprefresh\fR and \fBpnoutrefresh\fR routines are analogous to
\fBwrefresh\fR and \fBwnoutrefresh\fR except that they relate to pads instead
-of windows. The additional parameters are needed to indicate what part of the
-pad and screen are involved. \fIpminrow\fR and \fIpmincol\fR specify the upper
-left-hand corner of the rectangle to be displayed in the pad. \fIsminrow\fR,
-\fIsmincol\fR, \fIsmaxrow\fR, and \fIsmaxcol\fR specify the edges of the
-rectangle to be displayed on the screen. The lower right-hand corner of the
+of windows.
+The additional parameters are needed to indicate what part of the
+pad and screen are involved.
+.bP
+The \fIpminrow\fR and \fIpmincol\fR parameters specify the upper
+left-hand corner of the rectangle to be displayed in the pad.
+.bP
+The \fIsminrow\fR,
+\fIsmincol\fR, \fIsmaxrow\fR, and \fIsmaxcol\fR
+parameters specify the edges of the
+rectangle to be displayed on the screen.
+.PP
+The lower right-hand corner of the
rectangle to be displayed in the pad is calculated from the screen coordinates,
-since the rectangles must be the same size. Both rectangles must be entirely
-contained within their respective structures. Negative values of
+since the rectangles must be the same size.
+Both rectangles must be entirely
+contained within their respective structures.
+Negative values of
\fIpminrow\fR, \fIpmincol\fR, \fIsminrow\fR, or \fIsmincol\fR are treated as if
they were zero.
-
+.SS pechochar
+.PP
The \fBpechochar\fR routine is functionally equivalent to a call to \fBaddch\fR
-followed by a call to \fBrefresh\fR, a call to \fBwaddch\fR followed by a call
+followed by a call to \fBrefresh\fR(3X),
+a call to \fBwaddch\fR followed by a call
to \fBwrefresh\fR, or a call to \fBwaddch\fR followed by a call to
-\fBprefresh.\fR The knowledge that only a single character is being output is
+\fBprefresh\fR.
+The knowledge that only a single character is being output is
taken into consideration and, for non-control characters, a considerable
performance gain might be seen by using these routines instead of their
-equivalents. In the case of \fBpechochar\fR, the last location of the pad on
+equivalents.
+In the case of \fBpechochar\fR, the last location of the pad on
the screen is reused for the arguments to \fBprefresh\fR.
+.SS pecho_wchar
+.PP
+The \fBpecho_wchar\fR function is the analogous wide-character
+form of \fBpechochar\fR.
+It outputs one character to a pad and immediately refreshes the pad.
+It does this by a call to \fBwadd_wch\fR followed by a call to \fBprefresh\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
Routines that return pointers return \fBNULL\fR on error, and set \fBerrno\fR
-to \fBENOMEM\fR.
+to \fBENOMEM\fR.
+.PP
+X/Open does not define any error conditions.
+In this implementation
+.RS 3
+.TP 5
+\fBprefresh\fP and \fBpnoutrefresh\fP
+return an error
+if the window pointer is null, or
+if the window is not really a pad or
+if the area to refresh extends off-screen or
+if the minimum coordinates are greater than the maximum.
+.TP 5
+\fBpechochar\fP
+returns an error
+if the window is not really a pad, and the associated call
+to \fBwechochar\fP returns an error.
+.TP 5
+\fBpecho_wchar\fP
+returns an error
+if the window is not really a pad, and the associated call
+to \fBwecho_wchar\fP returns an error.
+.RE
.SH NOTES
Note that \fBpechochar\fR may be a macro.
.SH PORTABILITY
-The XSI Curses standard, Issue 4 describes these functions.
+BSD curses has no \fIpad\fP feature.
+.PP
+SVr2 curses (1986) provided the \fBnewpad\fP and related functions,
+documenting them in a single line each.
+SVr3 (1987) provided more extensive documentation.
+.PP
+The documentation does not explain the term \fIpad\fP.
+However, the Apollo \fIAegis\fP workstation operating system
+supported a graphical \fIpad\fP feature:
+.bP
+These graphical pads could be much larger than the computer's display.
+.bP
+The read-only output from a command could be scrolled back to inspect,
+and select text from the pad.
+.PP
+The two uses may be related.
+.PP
+The XSI Curses standard, Issue 4 describes these functions,
+without significant change from the SVr3 documentation.
+It describes no error conditions.
+The behavior of \fBsubpad\fP if the parent window is not
+a pad is undocumented,
+and is not checked by the vendor Unix implementations:
+.bP
+SVr4 curses sets a flag in the \fBWINDOW\fP structure in \fBnewpad\fP
+which tells if the window is a \fIpad\fP.
+.IP
+However, it uses this information only in
+\fBwaddch\fP (to decide if it should call \fBwrefresh\fP) and
+\fBwscrl\fP (to avoid scrolling a pad),
+and does not check in \fBwrefresh\fP to ensure that the pad
+is refreshed properly.
+.bP
+Solaris X/Open Curses checks if a window is a pad in \fBwnoutrefresh\fP,
+returning \fBERR\fP in that case.
+.IP
+However, it only sets the flag for subwindows if the parent window is a pad.
+Its \fBnewpad\fP function does not set this information.
+Consequently, the check will never fail.
+.IP
+It makes no comparable check in \fBpnoutrefresh\fP,
+though interestingly enough, a comment in the source code
+states that the lack of a check was an MKS extension.
+.bP
+NetBSD 7 curses
+sets a flag in the \fBWINDOW\fP structure for \fBnewpad\fP and \fBsubpad\fP,
+using this to help with the distinction between \fBwnoutrefresh\fP
+and \fBpnoutrefresh\fP.
+.IP
+It does not check for the case where a subwindow is created in
+a pad using \fBsubwin\fP or \fBderwin\fP.
+.IP
+The \fBdupwin\fP function returns a regular window when duplicating a pad.
+Likewise, \fBgetwin\fP always returns a window, even if the saved
+data was from a pad.
+.PP
+This implementation
+.bP
+sets a flag in the \fBWINDOW\fP structure for \fBnewpad\fP and \fBsubpad\fP,
+.bP
+allows a \fBsubwin\fP or \fBderwin\fP call to succeed having a pad parent by
+forcing the subwindow to be a pad,
+.bP
+checks in both \fBwnoutrefresh\fP and \fBpnoutrefresh\fP to ensure
+that pads and windows are handled distinctly, and
+.bP
+ensures that \fBdupwin\fP and \fBgetwin\fP treat
+pads versus windows consistently.
.SH SEE ALSO
-\fBcurses\fR(3X), \fBcurs_refresh\fR(3X), \fBcurs_touch\fR(3X), \fBcurs_addch\fR(3X).
-.\"#
-.\"# The following sets edit modes for GNU EMACS
-.\"# Local Variables:
-.\"# mode:nroff
-.\"# fill-column:79
-.\"# End:
+\fBcurses\fR(3X),
+\fBcurs_refresh\fR(3X),
+\fBcurs_touch\fR(3X),
+\fBcurs_addch\fR(3X).
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