Provided by: ncurses-doc_6.1+20190803-1ubuntu1_all bug


       is_term_resized, resize_term, resizeterm - change the curses terminal size


       #include <curses.h>

       bool is_term_resized(int lines, int columns);
       int resize_term(int lines, int columns);
       int resizeterm(int lines, int columns);


       This  is  an  extension  to  the curses library.  It provides callers with a hook into the
       ncurses data to resize windows, primarily for use by  programs  running  in  an  X  Window
       terminal (e.g., xterm).

       The  function  resizeterm  resizes  the  standard  and  current  windows  to the specified
       dimensions, and adjusts other bookkeeping data used by the ncurses library that record the
       window dimensions such as the LINES and COLS variables.

       Most of the work is done by the inner function resize_term.  The outer function resizeterm
       adds bookkeeping for the SIGWINCH handler.  When resizing the windows, resize_term  blank-
       fills  the  areas  that  are extended.  The calling application should fill in these areas
       with appropriate data.  The resize_term function attempts to resize all windows.  However,
       due  to  the  calling  convention  of  pads,  it  is  not possible to resize these without
       additional interaction with the application.

       A support function is_term_resized is provided so  that  applications  can  check  if  the
       resize_term  function  would modify the window structures.  It returns TRUE if the windows
       would be modified, and FALSE otherwise.


       Except as noted, these functions return the integer ERR upon failure and  OK  on  success.
       They  will fail if either of the dimensions are less than or equal to zero, or if an error
       occurs while (re)allocating memory for the windows.


       While these functions are intended to be used to  support  a  signal  handler  (i.e.,  for
       SIGWINCH),  care  should  be  taken  to  avoid  invoking them in a context where malloc or
       realloc may have been interrupted, since it uses those functions.

       If ncurses is configured to supply its own SIGWINCH handler,

       ·   on receipt of a SIGWINCH, the handler sets a flag

       ·   which is tested in wgetch(3X) and doupdate,

       ·   in turn, calling the resizeterm function,

       ·   which ungetch's a KEY_RESIZE which will be read on the next call to wgetch.

           The KEY_RESIZE alerts an application that the screen size has  changed,  and  that  it
           should repaint special features such as pads that cannot be done automatically.

           Calling  resizeterm  or  resize_term  directly  from a signal handler is unsafe.  This
           indirect method is used to provide a safe way to resize the ncurses data structures.

       If the environment variables LINES or COLUMNS are set, this overrides the library's use of
       the window size obtained from the operating system.  Thus, even if a SIGWINCH is received,
       no screen size change may be recorded.


       It is possible to resize the screen with SVr4 curses, by

       ·   exiting curses with endwin(3X) and

       ·   resuming using refresh(3X).

       Doing that clears the screen and is visually distracting.

       This extension of ncurses was introduced in mid-1995.  It was  adopted  in  NetBSD  curses
       (2001) and PDCurses (2003).


       getch(3NCURSES), curses_variables(3NCURSES), wresize(3NCURSES).


       Thomas Dickey (from an equivalent function written in 1988 for BSD curses).