ncurses 6.0 - patch 20171028

[ncurses.git] / man / curs_inch.3x

diff --git a/man/curs_inch.3x b/man/curs_inch.3x
index bcc8d6f85c60937dbb8ddbda71ba4e2efa7dab78..3386900ad089e88765f7cceca8debb74466783d2 100644 (file)
--- a/man/curs_inch.3x
+++ b/man/curs_inch.3x
@@ -1,6 +1,6 @@
 '\" t
 .\"***************************************************************************
-.\" Copyright (c) 1998 Free Software Foundation, Inc.                        *
+.\" Copyright (c) 1998-2010,2017 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            *
@@ -27,14 +27,19 @@
 .\" authorization.                                                           *
 .\"***************************************************************************
 .\"
-.\" $Id: curs_inch.3x,v 1.11 1998/11/29 01:04:34 Rick.Ohnemus Exp $
+.\" $Id: curs_inch.3x,v 1.19 2017/10/28 20:16:52 Sven.Joachim Exp $
 .TH curs_inch 3X ""
+.de bP
+.IP \(bu 4
+..
 .SH NAME
-\fBinch\fR, \fBwinch\fR, \fBmvinch\fR, \fBmvwinch\fR
-- get a character and attributes from a \fBcurses\fR window
+\fBinch\fR,
+\fBwinch\fR,
+\fBmvinch\fR,
+\fBmvwinch\fR \- get a character and attributes from a \fBcurses\fR window
 .SH SYNOPSIS
 \fB#include <curses.h>\fR
-
+.sp
 \fBchtype inch(void);\fR
 .br
 \fBchtype winch(WINDOW *win);\fR
@@ -49,25 +54,58 @@ position in the named window.  If any attributes are set for that position,
 their values are OR'ed into the value returned.  Constants defined in
 \fB<curses.h>\fR can be used with the \fB&\fR (logical AND) operator to
 extract the character or attributes alone.
-
+.
 .SS Attributes
 The following bit-masks may be AND-ed with characters returned by \fBwinch\fR.
-
+.
 .TS
 l l .
 \fBA_CHARTEXT\fR       Bit-mask to extract character
 \fBA_ATTRIBUTES\fR     Bit-mask to extract attributes
 \fBA_COLOR\fR  Bit-mask to extract color-pair field information
 .TE
+.SH RETURN VALUE
+Functions with a "mv" prefix first perform a cursor movement using
+\fBwmove\fP, and return an error if the position is outside the window,
+or if the window pointer is null.
+.PP
+The \fBwinch\fP function does not return an error if the window contains
+characters larger than 8-bits (255).
+Only the low-order 8 bits of the character are used by \fBwinch\fP.
 .SH NOTES
 Note that all of these routines may be macros.
 .SH PORTABILITY
 These functions are described in the XSI Curses standard, Issue 4.
+.PP
+Very old systems (before standardization) provide a different function
+with the same name:
+.bP
+The \fBwinch\fP function was part of the original BSD curses library,
+which stored a 7-bit character combined with the \fIstandout\fP attribute.
+.IP
+In BSD curses, \fBwinch\fP returned only the character (as an integer)
+with the \fIstandout\fP attribute removed.
+.bP
+System V curses added support for several video attributes which
+could be combined with characters in the window.
+.IP
+Reflecting this improvement, the function was altered to return the
+character combined with all video attributes in a \fBchtype\fP value.
+.PP
+X/Open Curses does not specify 
+the size and layout of attributes, color and character values in
+\fBchtype\fP; it is implementation-dependent.
+This implementation uses 8 bits for character values.
+An application using more bits, e.g., a Unicode value,
+should use the wide-character equivalents to these functions.
 .SH SEE ALSO
-\fBcurses\fR(3X).
-.\"#
-.\"# The following sets edit modes for GNU EMACS
-.\"# Local Variables:
-.\"# mode:nroff
-.\"# fill-column:79
-.\"# End:
+.TP 5
+\fBcurses\fR(3X)
+gives an overview of the WINDOW and \fBchtype\fP data types.
+.TP 5
+\fBcurs_attr\fR(3X)
+goes into more detail, pointing out portability problems and
+constraints on the use of \fBchtype\fP for returning window information.
+.TP 5
+\fBcurs_in_wch\fR(3X)
+describes comparable functions for the wide-character (ncursesw) library.