+
#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);
+ 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,
@@ -78,6 +81,9 @@
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
@@ -86,27 +92,48 @@
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 es-
- caping from curses mode temporarily. This routine re-
- stores 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.
+ 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
@@ -114,6 +141,9 @@
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-
@@ -121,27 +151,48 @@
-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 implementa-
- tion endwin returns an error if the terminal was not ini-
- tialized.
+ 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.
-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.
+
+ These functions were described in the XSI Curses standard,
+ Issue 4. As of 2015, the current document is X/Open Curs-
+ es, Issue 7.
+
+
+
+
+ X/Open specifies that portable applications must not call
+ initscr more than once:
+
+ o The portable way to use initscr is once only, using
+ refresh (see curs_refresh(3x)) to restore the screen
+ after endwin.
+
+ o This implementation allows using initscr after endwin.
Old versions of curses, e.g., BSD 4.4, may have returned a
null pointer from initscr when an error is detected,
@@ -150,18 +201,114 @@
-SEE ALSO
+
+ 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 (see curs_terminfo(3x)) and can-
+ not be used for full-screen operation. Other implementa-
+ tions may handle a missing/empty TERM variable different-
+ ly.
+
+
+
+
+ Quoting from X/Open Curses, section 3.1.1:
+
+ Curses implementations may provide for special han-
+ dling of the SIGINT, SIGQUIT and SIGTSTP signals if
+ their disposition is SIG_DFL at the time initscr() is
+ called ...
+
+ Any special handling for these signals may remain in
+ effect for the life of the process or until the
+ process changes the disposition of the signal.
+
+ None of the Curses functions are required to be safe
+ with respect to signals ...
+
+ This implementation establishes signal handlers during
+ initialization, e.g., initscr or newterm. Applications
+ which must handle these signals should set up the corre-
+ sponding handlers after initializing the library:
+
+ SIGINT
+ The handler attempts to cleanup the screen on exit.
+ Although it usually works as expected, there are lim-
+ itations:
+
+ o Walking the SCREEN list is unsafe, since all list
+ management is done without any signal blocking.
+
+ o On systems which have REENTRANT turned on,
+ set_term uses functions which could deadlock or
+ misbehave in other ways.
+
+ o endwin calls other functions, many of which use
+ stdio or other library functions which are clear-
+ ly unsafe.
+
+ SIGTERM
+ This uses the same handler as SIGINT, with the same
+ limitations. It is not mentioned in X/Open Curses,
+ but is more suitable for this purpose than SIGQUIT
+ (which is used in debugging).
+
+ SIGTSTP
+ This handles the stop signal, used in job control.
+ When resuming the process, this implementation dis-
+ cards pending input with flushinput (see
+ curs_util(3x)), and repaints the screen assuming that
+ it has been completely altered. It also updates the
+ saved terminal modes with def_shell_mode (see
+ curs_kernel(3x)).
+
+ SIGWINCH
+ This handles the window-size changes which were ini-
+ tially ignored in the standardization efforts. The
+ handler sets a (signal-safe) variable which is later
+ tested in wgetch (see curs_getch(3x)). If keypad has
+ been enabled for the corresponding window, wgetch re-
+ turns the key symbol KEY_RESIZE. At the same time,
+ wgetch calls resizeterm to adjust the standard screen
+ stdscr, and update other data such as LINES and COLS.
+
+
+
+
curses(3x), curs_kernel(3x), curs_refresh(3x),
- curs_slk(3x), curs_util(3x), curs_variables(3x).
+ curs_slk(3x), curs_terminfo(3x), curs_util(3x), curs_vari-
+ ables(3x).
curs_initscr(3x)
-
-
-Man(1) output converted with
-man2html
-
+