# resizeterm 3x

    resizeterm(3x)                                                  resizeterm(3x)

## NAME

           is_term_resized,  resize_term,  resizeterm - change the curses terminal
           size

## SYNOPSIS

           #include <curses.h>

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

## DESCRIPTION

           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 pro-
           grams running in an X Window terminal (e.g., xterm).

### resizeterm

           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.

### resize_term

           Most  of the work is done by the inner function resize_term.  The outer
           function resizeterm adds bookkeeping for the SIGWINCH handler, as  well
           as repainting the soft-key area (see slk_touch(3x)).

           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.

           When  resizing  windows,  resize_term  recursively  adjusts subwindows,
           keeping them within the updated parent window's limits.  If a top-level
           window  happens  to extend to the screen's limits, then on resizing the
           window, resize_term will keep the window extending to the corresponding
           limit, regardless of whether the screen has shrunk or grown.

### is_term_resized

           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.

## RETURN VALUE

           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 mem-
           ory for the windows.

## NOTES

           While these functions are intended to be used to support a signal  han-
           dler  (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,

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

           o   which is tested in wgetch(3x) and doupdate,

           o   in turn, calling the resizeterm function,

           o   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 sys-
           tem.  Thus, even if a SIGWINCH is received, no screen size  change  may
           be recorded.

## PORTABILITY

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

           o   exiting curses with endwin(3x) and

           o   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).

## SEE ALSO

           curs_getch(3x), curs_variables(3x), wresize(3x).

## AUTHOR

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

                                                                    resizeterm(3x)