'\" t
.\"***************************************************************************
-.\" Copyright (c) 1998-2007,2010 Free Software Foundation, Inc. *
+.\" Copyright (c) 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_addch.3x,v 1.28 2010/07/31 16:12:01 tom Exp $
+.\" $Id: curs_addch.3x,v 1.41 2017/05/05 18:15:29 tom Exp $
.TH curs_addch 3X ""
+.ie \n(.g .ds `` \(lq
+.el .ds `` ``
+.ie \n(.g .ds '' \(rq
+.el .ds '' ''
+.de bP
+.IP \(bu 4
+..
.SH NAME
-\fBaddch\fR, \fBwaddch\fR, \fBmvaddch\fR, \fBmvwaddch\fR,
+\fBaddch\fR,
+\fBwaddch\fR,
+\fBmvaddch\fR,
+\fBmvwaddch\fR,
\fBechochar\fR,
\fBwechochar\fR \- add a character (with attributes) to a \fBcurses\fR window, then advance the cursor
.SH SYNOPSIS
\fBint wechochar(WINDOW *win, const chtype ch);\fR
.br
.SH DESCRIPTION
+.SS Adding characters
The \fBaddch\fR, \fBwaddch\fR, \fBmvaddch\fR and \fBmvwaddch\fR routines put
the character \fIch\fR into the given window at its current window position,
-which is then advanced. They are analogous to \fBputchar\fR in \fBstdio\fR(3).
-If the advance is at the right margin, the cursor automatically wraps to the
-beginning of the next line. At the bottom of the current scrolling region, if
-\fBscrollok\fR is enabled, the scrolling region is scrolled up one line.
+which is then advanced. They are analogous to \fBputchar\fR(3) in \fBstdio\fR(3).
+If the advance is at the right margin:
+.bP
+The cursor automatically wraps to the beginning of the next line.
+.bP
+At the bottom of the current scrolling region,
+and if \fBscrollok\fR is enabled,
+the scrolling region is scrolled up one line.
+.bP
+If \fBscrollok\fR is not enabled,
+writing a character at the lower right margin succeeds.
+However, an error is returned because
+it is not possible to wrap to a new line
.PP
-If \fIch\fR is a tab, newline, or backspace,
-the cursor is moved appropriately within the window.
+If \fIch\fR is a tab, newline, carriage return or backspace,
+the cursor is moved appropriately within the window:
+.bP
Backspace moves the cursor one character left; at the left
edge of a window it does nothing.
+.bP
+Carriage return moves the cursor to the window left margin on the current line.
+.bP
Newline does a \fBclrtoeol\fR,
then moves the cursor to the window left margin on the next line,
scrolling the window if on the last line.
+.bP
Tabs are considered to be at every eighth column.
The tab interval may be altered by setting the \fBTABSIZE\fR variable.
.PP
-If \fIch\fR is any control character other than tab, newline, or backspace, it
+If \fIch\fR is any other control character, it
is drawn in \fB^\fR\fIX\fR notation. Calling \fBwinch\fR after adding a
control character does not return the character itself, but instead returns
the ^-representation of the control character.
Video attributes can be combined with a character argument passed to
\fBaddch\fR or related functions by logical-ORing them into the character.
(Thus, text, including attributes, can be copied from one place to another
-using \fBinch\fR and \fBaddch\fR.) See the \fBcurs_attr\fR(3X) page for
+using \fBinch\fR(3X) and \fBaddch\fR.) See the \fBcurs_attr\fR(3X) page for
values of predefined video attribute constants that can be usefully OR'ed
into characters.
+.SS Echoing characters
.PP
The \fBechochar\fR and \fBwechochar\fR routines are equivalent to a call to
-\fBaddch\fR followed by a call to \fBrefresh\fR, or a call to \fBwaddch\fR
+\fBaddch\fR followed by a call to \fBrefresh\fR(3X), or a call to \fBwaddch\fR
followed by a call to \fBwrefresh\fR. The knowledge that only a single
character is being output is used and, for non-control characters, a
considerable performance gain may be seen by using these routines instead of
The following variables may be used to add line drawing characters to the
screen with routines of the \fBaddch\fR family. The default character listed
below is used if the \fBacsc\fR capability does not define a terminal-specific
-replacement for it.
+replacement for it,
+or if the terminal and locale configuration requires Unicode but the
+library is unable to use Unicode.
+.PP
The names are taken from VT100 nomenclature.
.PP
.TS
-l l l
-_ _ _
-l l l.
-\fIName\fR \fIDefault\fR \fIDescription\fR
-ACS_BLOCK # solid square block
-ACS_BOARD # board of squares
-ACS_BTEE + bottom tee
-ACS_BULLET o bullet
-ACS_CKBOARD : checker board (stipple)
-ACS_DARROW v arrow pointing down
-ACS_DEGREE ' degree symbol
-ACS_DIAMOND + diamond
-ACS_GEQUAL > greater-than-or-equal-to
-ACS_HLINE \- horizontal line
-ACS_LANTERN # lantern symbol
-ACS_LARROW < arrow pointing left
-ACS_LEQUAL < less-than-or-equal-to
-ACS_LLCORNER + lower left-hand corner
-ACS_LRCORNER + lower right-hand corner
-ACS_LTEE + left tee
-ACS_NEQUAL ! not-equal
-ACS_PI * greek pi
-ACS_PLMINUS # plus/minus
-ACS_PLUS + plus
-ACS_RARROW > arrow pointing right
-ACS_RTEE + right tee
-ACS_S1 \- scan line 1
-ACS_S3 \- scan line 3
-ACS_S7 \- scan line 7
-ACS_S9 \&_ scan line 9
-ACS_STERLING f pound-sterling symbol
-ACS_TTEE + top tee
-ACS_UARROW ^ arrow pointing up
-ACS_ULCORNER + upper left-hand corner
-ACS_URCORNER + upper right-hand corner
-ACS_VLINE | vertical line
+l l l l
+l l l l
+_ _ _ _
+l l l l.
+\fBACS\fR \fBACS\fR \fBacsc\fP \fBGlyph\fR
+\fBName\fR \fBDefault\fR \fBchar\fP \fBName\fR
+ACS_BLOCK # 0 solid square block
+ACS_BOARD # h board of squares
+ACS_BTEE + v bottom tee
+ACS_BULLET o ~ bullet
+ACS_CKBOARD : a checker board (stipple)
+ACS_DARROW v . arrow pointing down
+ACS_DEGREE ' f degree symbol
+ACS_DIAMOND + ` diamond
+ACS_GEQUAL > > greater-than-or-equal-to
+ACS_HLINE \- q horizontal line
+ACS_LANTERN # i lantern symbol
+ACS_LARROW < , arrow pointing left
+ACS_LEQUAL < y less-than-or-equal-to
+ACS_LLCORNER + m lower left-hand corner
+ACS_LRCORNER + j lower right-hand corner
+ACS_LTEE + t left tee
+ACS_NEQUAL ! | not-equal
+ACS_PI * { greek pi
+ACS_PLMINUS # g plus/minus
+ACS_PLUS + n plus
+ACS_RARROW > + arrow pointing right
+ACS_RTEE + u right tee
+ACS_S1 \- o scan line 1
+ACS_S3 \- p scan line 3
+ACS_S7 \- r scan line 7
+ACS_S9 \&_ s scan line 9
+ACS_STERLING f } pound-sterling symbol
+ACS_TTEE + w top tee
+ACS_UARROW ^ \- arrow pointing up
+ACS_ULCORNER + l upper left-hand corner
+ACS_URCORNER + k upper right-hand corner
+ACS_VLINE | x vertical line
.TE
.SH RETURN VALUE
All routines return the integer \fBERR\fR upon failure and \fBOK\fR on success
-(the SVr4 manuals specify only "an integer value other than \fBERR\fR") upon
-successful completion, unless otherwise noted in the preceding routine
-descriptions.
+(the SVr4 manuals specify only
+\*(``an integer value other than \fBERR\fR\*('') upon successful completion,
+unless otherwise noted in the preceding routine descriptions.
+.PP
+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.
.SH NOTES
Note that \fBaddch\fR, \fBmvaddch\fR, \fBmvwaddch\fR, and
\fBechochar\fR may be macros.
All these functions are described in the XSI Curses standard, Issue 4.
The defaults specified for forms-drawing characters apply in the POSIX locale.
.LP
+X/Open Curses states that the \fIACS_\fP definitions are \fBchar\fP constants.
+For the wide-character implementation (see \fBcurs_add_wch\fP),
+there are analogous \fIWACS_\fP definitions which are \fBcchar_t\fP constants.
+.LP
Some ACS symbols
(ACS_S3,
ACS_S7,
embedded, and a second-hand list of their character descriptions has come
to light. The ACS-prefixed names for them were invented for \fBncurses\fR(3X).
.LP
+The \fIdisplayed\fP values for the \fIACS_\fP and \fIWACS_\fP constants
+depend on
+.bP
+the library configuration, i.e., \fBncurses\fP versus \fBncursesw\fP,
+where the latter is capable of displaying Unicode while the former is not, and
+.bP
+whether the \fIlocale\fP uses UTF-8 encoding.
+.LP
+In certain cases, the terminal is unable to display line-drawing characters
+except by using UTF-8 (see the discussion of \fBNCURSES_NO_UTF8_ACS\fP in
+ncurses(3X)).
+.LP
The \fBTABSIZE\fR variable is implemented in some versions of curses,
but is not part of X/Open curses.
.LP
\fBcurs_inch\fR(3X),
\fBcurs_outopts\fR(3X),
\fBcurs_refresh\fR(3X),
+\fBcurs_variables\fR(3X),
\fBputc\fR(3).
.PP
Comparable functions in the wide-character (ncursesw) library are
described in
\fBcurs_add_wch\fR(3X).
-.\"#
-.\"# The following sets edit modes for GNU EMACS
-.\"# Local Variables:
-.\"# mode:nroff
-.\"# fill-column:79
-.\"# End:
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