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resizeterm(3)                                                  resizeterm(3)




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);
       resizeterm(3) 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.   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 win-
       dows.  However, due to the calling convention of pads, it is not possi-
       ble  to  resize  these without additional interaction with the applica-
       tion.

   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(3)

ncurses 6.0 - Generated Sun May 7 14:47:55 CDT 2017
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