ncurses 6.0 - patch 20171118

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

diff --git a/man/curs_inch.3x b/man/curs_inch.3x
index 7e1e3b439177b5694afa9930506c02441138bcbc..97eb981f43a270e88559bf5270660173d89f230b 100644 (file)
--- a/man/curs_inch.3x
+++ b/man/curs_inch.3x
@@ -1,6 +1,6 @@
 '\" t
 .\"***************************************************************************
-.\" Copyright (c) 1998-2006,2010 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            *
@@ -27,8 +27,12 @@
 .\" authorization.                                                           *
 .\"***************************************************************************
 .\"
-.\" $Id: curs_inch.3x,v 1.17 2010/12/04 18:36:44 tom Exp $
+.\" $Id: curs_inch.3x,v 1.20 2017/11/18 23:47:37 tom Exp $
 .TH curs_inch 3X ""
+.de bP
+.ie n  .IP \(bu 4
+.el    .IP \(bu 2
+..
 .SH NAME
 \fBinch\fR,
 \fBwinch\fR,
@@ -65,13 +69,44 @@ l l .
 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.
-.SH SEE ALSO
-\fBcurses\fR(3X).
 .PP
-Comparable functions in the wide-character (ncursesw) library are
-described in
-\fBcurs_in_wch\fR(3X).
+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
+.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.