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
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
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.
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.