initscr, newterm, endwin, isendwin, set_term, delscreen - curses screen
initialization and manipulation routines
SCREEN *newterm(char *type, FILE *outfd, FILE *infd);
SCREEN *set_term(SCREEN *new);
void delscreen(SCREEN* sp);
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. newterm's 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 the type parameter 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
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.
endwin returns the integer ERR upon failure and OK upon successful
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.
· newterm returns an error if it cannot allocate the data structures
for the screen, or for the top-level windows within the screen,
i.e., curscr, newscr, or stdscr.
· set_term returns no error.
Note that initscr and newterm may be macros.
These functions are described in the XSI Curses standard, Issue 4. It
specifies that portable applications must not call initscr more than
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.
If the TERM variable is missing or empty, initscr uses the value
“unknown”, which normally corresponds to a terminal entry with the
generic (gn) capability. Generic entries are detected by setupterm(3X)
and cannot be used for full-screen operation. Other implementations
may handle a missing/empty TERM variable differently.
ncurses(3NCURSES), kernel(3NCURSES), refresh(3NCURSES), slk(3NCURSES),
terminfo(3NCURSES), util(3NCURSES), curses_variables(3NCURSES).