curses_screen(3) - NetBSD Manual Pages

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CURSES_SCREEN(3)        NetBSD Library Functions Manual       CURSES_SCREEN(3)


NAME

     curses_screen, filter, ripoffline, use_env, newterm, set_term, delscreen,
     endwin, initscr, isendwin, is_term_resized, resize_term, resizeterm,
     setterm, set_tabsize -- curses terminal and screen routines


LIBRARY

     Curses Library (libcurses, -lcurses)


SYNOPSIS

     #include <curses.h>

     void
     filter(void);

     int
     ripoffline(int line, int (*init)(WINDOW *win, int cols));

     void
     use_env(bool value);

     SCREEN *
     newterm(char *type, FILE *outfd, FILE *infd);

     SCREEN *
     set_term(SCREEN *screen);

     void
     delscreen(SCREEN *screen);

     int
     endwin(void);

     WINDOW *
     initscr(void);

     bool
     isendwin(void);

     bool
     is_term_resized(int lines, int cols);

     int
     resize_term(int lines, int cols);

     int
     resizeterm(int lines, int cols);

     int
     setterm(char *name);

     int
     set_tabsize(int value);

     extern int LINES;

     extern int COLS;


DESCRIPTION

     These functions initialize terminals and screens.

     The newterm() function initialises the curses data structures and point-
     ers ready for use by curses.  The type argument points to a terminfo(5)
     entry, or it may be NULL in which case the TERM environment variable is
     used.  The outfd and infd are the output and input file descriptors for
     the terminal.  The newterm() function must only be called once  per ter-
     minal.

     The set_term() function can be used to switch between the screens defined
     by calling newterm(), a pointer to the previous screen structure that was
     in use will be returned on success.

     Calling delscreen() will destroy the given screen and free all allocated
     resources.

     Calling endwin() will end the curses session and restore the saved termi-
     nal settings.

     The curses session must be initialised by calling initscr() which saves
     the current terminal state and sets up the terminal and internal data
     structures to support the curses application.  This function call must
     be, with few exceptions, the first Curses library call made.  The excep-
     tion to this rule is the newterm() call which may be called prior to
     initscr().  The size of the curses screen is determined by checking the
     tty(4) size and then the terminfo(5) entries for the terminal type.  If
     the environment variables LINES or COLUMNS are set, then these will be
     used instead.

     When either newterm() or initscr() are called, the Curses library sets up
     signal handlers for SIGTSTP and SIGWINCH.  If a signal handler is already
     installed for SIGWINCH, this will also be called when the Curses library
     handler is called.

     The isendwin() function can be used to determine whether or not a refresh
     of the screen has occurred since the last call to endwin().

     The size of the screen may be changed by calling resize_term() with the
     updated number of lines and columns.  This will resize the curses inter-
     nal data structures to accommodate the changed terminal geometry.  The
     curscr and stdscr windows and any of their subwindows will be resized to
     fit the new screen size.  The application must redraw the screen after a
     call to resize_term().  The resizeterm() function is a wrapper for
     resize_term() and adjusts other structure data that handles window dimen-
     sions.  The is_term_resized() function tests if either of the above func-
     tions need to be called.

     The setterm() function sets the terminal type for the current screen to
     the one passed, initialising all the curses internal data structures with
     information related to the named terminal.  The name argument must be a
     valid name or alias in the terminfo(5) database for this function to suc-
     ceed.

     The filter() function changes the way the terminal is initialised.  A
     subsequent call to initscr() or newterm() performs the following addi-
     tional actions:
     ·   Disable use of clear, cud, cud1, cup, cuu, cuu1 and vpa.
     ·   Set the value of the home string to the value of the cr string.
     ·   Set lines equal to 1.

     The ripoffline() function will rip a line from stdscr at the top if line
     is positive, or at the bottom if negative.  When initscr() or newterm()
     is called, a window will be created for each line ripped and passed to
     the init function pointer alongwith the number of columns in the window.
     This init function cannot use the LINES or COLS variables and cannot call
     wrefresh(3) or doupdate(3), but may call wnoutrefresh(3).  ripoffline()
     can be called up to five times.

     The use_env() function determines whether the environment variables LINES
     and COLUMNS override the normal values.  The default is true.  Any call
     to use_env() must precede calls to initscr(), newterm(), or setupterm().

     The set_tabsize() function will set TABSIZE of the current screen to
     tabsize.


RETURN VALUES

     Functions returning pointers will return NULL if an error is detected
     with the exception of initscr() which will log a diagnostic to standard
     error output and then call exit(3).  The functions that return an int
     will return one of the following values:

     OK   The function completed successfully.
     ERR  An error occurred in the function.


SEE ALSO

     curses_window(3), tty(4), terminfo(5), signal(7)


STANDARDS

     The NetBSD Curses library complies with the X/Open Curses specification,
     part of the Single Unix Specification.


HISTORY

     The Curses package appeared in 4.0BSD.  The resizeterm() function is an
     ncurses extension to the Curses library and was added in NetBSD 1.6.  The
     is_term_resized(), resize_term() and set_tabsize() functions are ncurses
     extensions to the Curses library and were added in NetBSD 8.0.


BUGS

     There is currently an issue with cursor movement in a 1 line sized window
     which causes the screen to scroll up.  This can obviously be seen when
     using ripoffline().

NetBSD 10.1                     March 12, 2020                     NetBSD 10.1