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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
       programs 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
       memory for the windows.


NOTES

       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,

       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
       system.  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)