curs_initscr(3x) curs_initscr(3x)
initscr, newterm, endwin, isendwin, set_term, delscreen -
curses screen initialization and manipulation routines
#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);
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 initial-
izes all curses data structures. initscr also causes the
first call to refresh to clear the screen. If errors oc-
cur, initscr writes an appropriate error message to stan-
dard 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 ter-
minal 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
o the type of the terminal to be used in place of $TERM,
o a file pointer for output to the terminal, and
o 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 es-
caping from curses mode temporarily. This routine
o restores tty modes,
o moves the cursor to the lower left-hand corner of the
screen and
o resets the terminal into the proper non-visual mode.
Calling refresh or doupdate after a temporary escape caus-
es 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 cur-
rent terminal. The previous terminal is returned by the
routine. This is the only routine which manipulates
SCREEN pointers; all other routines affect only the cur-
rent 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 par-
ticular SCREEN is no longer needed.
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 implementa-
tion
o endwin returns an error if the terminal was not ini-
tialized.
o newterm returns an error if it cannot allocate the da-
ta structures for the screen, or for the top-level
windows within the screen, i.e., curscr, newscr, or
stdscr.
o 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 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.
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 curs_terminfo(3x) and cannot be used for full-
screen operation. Other implementations may handle a
missing/empty TERM variable differently.
curses(3x), curs_kernel(3x), curs_refresh(3x),
curs_slk(3x), curs_terminfo(3x), curs_util(3x), curs_vari-
ables(3x).
curs_initscr(3x)