NAME
curses_screen
,
filter
, ripoffline
,
use_env
, newterm
,
set_term
, delscreen
,
endwin
, initscr
,
isendwin
, is_term_resized
,
resize_term
, resizeterm
,
setterm
, set_tabsize
— curses terminal and screen
routines
LIBRARY
library “libcurses”
SYNOPSIS
#include
<curses.h>
void
filter
(void);
int
ripoffline
(int
line, int (*init)(WINDOW
*win, int cols));
void
use_env
(bool
value);
SCREEN *
newterm
(char
*type, FILE *outfd,
FILE *infd);
SCREEN *
set_term
(SCREEN
*screen);
void
delscreen
(SCREEN
*screen);
int
endwin
(void);
WINDOW *
initscr
(void);
bool
isendwin
(void);
bool
is_term_resized
(int
lines, int
cols);
int
resize_term
(int
lines, int
cols);
int
resizeterm
(int
lines, int
cols);
int
setterm
(char
*name);
int
set_tabsize
(int
value);
extern int LINES;
extern int COLS;
DESCRIPTION
These functions initialize terminals and screens.The
newterm
()
function initialises the curses data structures and pointers ready for use
by curses. The type argument points to a
terminfo(5) entry, or it may be NULL
in which
case the TERM environment variable is used. The outfd
and infd are the output and input file descriptors for
the terminal. The newterm
() function must only be
called once per terminal.
The
set_term
()
function can be used to switch between the screens defined by calling
newterm
(), a pointer to the previous screen
structure that was in use will be returned on success.
Calling
delscreen
()
will destroy the given screen and free all allocated resources.
Calling
endwin
()
will end the curses session and restore the saved terminal settings.
The curses session must be initialised by calling
initscr
()
which saves the current terminal state and sets up the terminal and internal
data structures to support the curses application. This function call must
be, with few exceptions, the first Curses library call made. The exception
to this rule is the newterm
() call which may be
called prior to initscr
(). The size of the curses
screen is determined by checking the
tty(4) size and then the
terminfo(5) entries for the terminal type. If the environment
variables LINES
or COLUMNS
are set, then these will be used instead.
When either
newterm
()
or initscr
() are called, the Curses library sets up
signal handlers for SIGTSTP
and
SIGWINCH
. If a signal handler is already installed
for SIGWINCH
, this will also be called when the
Curses library handler is called.
The
isendwin
()
function can be used to determine whether or not a refresh of the screen has
occurred since the last call to endwin
().
The size of the screen may be changed by calling
resize_term
()
with the updated number of lines and columns. This will resize the curses
internal data structures to accommodate the changed terminal geometry. The
curscr
and stdscr
windows
and any of their subwindows will be resized to fit the new screen size. The
application must redraw the screen after a call to
resize_term
(). The
resizeterm
()
function is a wrapper for resize_term
() and adjusts
other structure data that handles window dimensions. The
is_term_resized
()
function tests if either of the above functions need to be called.
The
setterm
()
function sets the terminal type for the current screen to the one passed,
initialising all the curses internal data structures with information
related to the named terminal. The name argument must
be a valid name or alias in the
terminfo(5) database for this function to succeed.
The
filter
()
function changes the way the terminal is initialised. A subsequent call to
initscr
() or newterm
()
performs the following additonal actions:
- Disable use of clear, cud, cud1, cup, cuu, cuu1 and vpa.
- Set the value of the home string to the value of the cr string.
- Set lines equal to 1.
The
ripoffline
()
function will rip a line from stdscr
at the top if
line is positive, or at the bottom if negative. When
initscr
() or newterm
() is
called, a window will be created for each line ripped and passed to the
init function pointer alongwith the number of columns
in the window. This init function cannot use the
LINES
or COLS
variables and
cannot call
wrefresh(3) or
doupdate(3), but may call
wnoutrefresh(3). ripoffline
() can be
called up to five times.
The
use_env
()
function determines whether the environment variables
LINES
and COLUMNS
override
the normal values. The default is true. Any call to
use_env
() must precede calls to
initscr
(), newterm
(), or
setupterm
().
The
set_tabsize
()
function will set TABSIZE of the current screen to
tabsize.
RETURN VALUES
Functions returning pointers will return
NULL
if an error is detected. The functions that
return an int will return one of the following values:
OK
- The function completed successfully.
ERR
- An error occurred in the function.
SEE ALSO
STANDARDS
The NetBSD Curses library complies with the X/Open Curses specification, part of the Single Unix Specification.
HISTORY
The Curses package appeared in 4.0BSD. The
resizeterm
() function is a ncurses
extension to the Curses library and was added in NetBSD
1.6. The is_term_resized
(),
resize_term
() and
set_tabsize
() functions are
ncurses extension to the Curses library and was added in
NetBSD 8.0.
BUGS
There is currently an issue with cursor movement in a 1 line sized
window which causes the screen to scroll up. This can obviously be seen when
using ripoffline
().