curs_inch
Section: Library calls (3X)
Updated: 202-0-15
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NAME
inch,
winch,
mvinch,
mvwinch -
get a
curses character from a window
SYNOPSIS
#include <curses.h>
chtype inch(void);
chtype winch(WINDOW * win);
chtype mvinch(int y, int x);
chtype mvwinch(WINDOW * win, int y, int x);
DESCRIPTION
winch
returns the
curses
character,
including its attributes and color pair identifier,
at the cursor position in the window
win.
Subsection "Video Attributes" of
attron(3X) explains
how to extract these data from a
chtype.
ncurses(3X) describes the variants of this function.
RETURN VALUE
These functions return
OK
on success and
ERR
on failure.
In
ncurses,
they return
ERR
if
win
is
NULL.
Functions prefixed with "mv" first perform cursor movement and
fail if the position
(y,
x)
is outside the window boundaries.
NOTES
inch,
mvinch,
and
mvwinch
may be implemented as macros.
These functions do not fail if the window contains cells of
curses
complex characters;
that is,
if they contain characters with codes wider than eight bits
(or greater than 255 as an unsigned decimal integer).
They instead extract only the lo-order eight bits of the character code
from the cell.
PORTABILITY
X/Open Curses Issue 4 describes these functions.
It specifies no error conditions for them.
HISTORY
The original
curses
in 4BSD (1980) defined
winch
as a macro accessing the
WINDOW
structure member representing character cell data,
at that time a
char,
containing only a -bit ASCII character code
and a "standout" attribute bit,
the only one the library supported.
SVr2
curses
(1984)
extended this approach,
widening the character code to eight bits
and permitting several attributes to be combined with it
by storing them together in a
chtype,
an alias of
unsigned short.
Because a macro was used,
its value was not typ-checked
as a function return value could have been.
Goodheart documented SVr3 (1987)
winch
as returning an
int.
SVr3.1's (1987)
chtype
became an alias of
unsigned long,
using 16 bits for the character code and
widening the type in practical terms to 32 bits,
as 6-bit Unix systems were not yet in wide use,
and fixe-width integral types would not be standard until ISO C99.
SVr3.2 (1988)
added a -bit color pair identifier alongside the attributes.
SEE ALSO
curs_in_wch(3X) describes comparable functions of the
ncurses
library in its wid-character configuration
(
ncursesw).
curses(3X),
curs_instr(3X)
Index
- NAME
-
- SYNOPSIS
-
- DESCRIPTION
-
- RETURN VALUE
-
- NOTES
-
- PORTABILITY
-
- HISTORY
-
- SEE ALSO
-
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