NAME¶
initscr,
newterm,
endwin,
isendwin,
set_term,
delscreen -
curses screen initialization and manipulation
routines
SYNOPSIS¶
#include <curses.h>
WINDOW *initscr(void);
int endwin(void);
bool isendwin(void);
SCREEN *newterm(char *type, FILE *outfd, FILE *infd);
SCREEN *set_term(SCREEN *new);
void delscreen(SCREEN* sp);
DESCRIPTION¶
initscr is normally the first
curses routine to call when
initializing a program. A few special routines sometimes need to be called
before it; these are
slk_init,
filter,
ripoffline,
use_env. For multiple-terminal applications,
newterm may be
called before
initscr.
The initscr code determines the terminal type and initializes all
curses
data structures.
initscr also causes the first call to
refresh
to clear the screen. If errors occur,
initscr writes an appropriate
error message to standard error and exits; otherwise, a pointer is returned to
stdscr.
A program that outputs to more than one terminal should use the
newterm
routine for each terminal instead of
initscr. A program that needs to
inspect capabilities, so it can continue to run in a line-oriented mode if the
terminal cannot support a screen-oriented program, would also use
newterm. The routine
newterm should be called once for each
terminal. It returns a variable of type
SCREEN * which should be saved
as a reference to that terminal. The arguments are the
type of the
terminal to be used in place of
$TERM, a file pointer for output to the
terminal, and another file pointer for input from the terminal (if
type
is
NULL,
$TERM will be used). The program must also call
endwin for each terminal being used before exiting from
curses.
If
newterm is called more than once for the same terminal, the first
terminal referred to must be the last one for which
endwin is called.
A program should always call
endwin before exiting or escaping from
curses mode temporarily. This routine restores tty modes, moves the
cursor to the lower left-hand corner of the screen and resets the terminal
into the proper non-visual mode. Calling
refresh or
doupdate
after a temporary escape causes the program to resume visual mode.
The
isendwin routine returns
TRUE if
endwin has been called
without any subsequent calls to
wrefresh, and
FALSE otherwise.
The
set_term routine is used to switch between different terminals. The
screen reference
new becomes the new current terminal. The previous
terminal is returned by the routine. This is the only routine which
manipulates
SCREEN pointers; all other routines affect only the current
terminal.
The
delscreen routine frees storage associated with the
SCREEN
data structure. The
endwin routine does not do this, so
delscreen should be called after
endwin if a particular
SCREEN is no longer needed.
RETURN VALUE¶
endwin returns the integer
ERR upon failure and
OK upon
successful completion.
Routines that return pointers always return
NULL on error.
X/Open defines no error conditions. In this implementation
endwin returns
an error if the terminal was not initialized.
NOTES¶
Note that
initscr and
newterm may be macros.
PORTABILITY¶
These functions are described in the XSI Curses standard, Issue 4. It specifies
that portable applications must not call
initscr more than once.
Old versions of curses, e.g., BSD 4.4, may have returned a null pointer from
initscr when an error is detected, rather than exiting. It is safe but
redundant to check the return value of
initscr in XSI Curses.
SEE ALSO¶
ncurses(3NCURSES),
kernel(3NCURSES),
refresh(3NCURSES),
slk(3NCURSES),
util(3NCURSES),
curses_variables(3NCURSES).
