man/curs_inch.3x

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.\" $Id: curs_inch.3x,v 1.51 2024/04/20 21:20:07 tom Exp $
.TH curs_inch 3X 2024-04-20 "ncurses @NCURSES_MAJOR@.@NCURSES_MINOR@" "Library calls"
.ie \n(.g \{\
.ds `` \(lq
.ds '' \(rq
.\}
.el \{\
.ie t .ds `` ``
.el   .ds `` ""
.ie t .ds '' ''
.el   .ds '' ""
.\}
.
.de bP
.ie n  .IP \(bu 4
.el    .IP \(bu 2
..
.SH NAME
\fB\%inch\fP,
\fB\%winch\fP,
\fB\%mvinch\fP,
\fB\%mvwinch\fP \-
get a \fIcurses\fR character from a window
.SH SYNOPSIS
.nf
\fB#include <curses.h>
.PP
\fBchtype inch(void);
\fBchtype winch(WINDOW *\fIwin\fP);
.PP
\fBchtype mvinch(int \fIy\fP, int \fIx\fP);
\fBchtype mvwinch(WINDOW *\fIwin\fP, int \fIy\fP, int \fIx\fP);
.fi
.SH DESCRIPTION
These routines return the character, of type \fBchtype\fP, at the current
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>\fP can be used with the \fB&\fP (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\fP.
.PP
.TS
Lb Lb
Lb Lx.
Name	Description
_
A_CHARTEXT	Extract character
A_ATTRIBUTES	Extract attributes
A_COLOR	Extract color pair information
.TE
.SH RETURN VALUE
Functions prefixed with \*(``mv\*('' first perform cursor movement and
fail if the position
.RI ( y ,
.IR x )
is outside the window boundaries.
.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 X/Open Curses, 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
\fB\%curs_in_wch\fP(3X) describes comparable functions of the
.I \%ncurses
library in its wide-character configuration
.RI ( \%ncursesw ).
.PP
\fB\%curses\fP(3X),
\fB\%curs_instr\fP(3X)