is_term_resized(3x) — Linux manual page


resizeterm(3X)                                                resizeterm(3X)

NAME         top

       is_term_resized, resize_term, resizeterm - change the curses terminal

SYNOPSIS         top

       #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         top

       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,
       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.

       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         top

       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         top

       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.

PORTABILITY         top

       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).

SEE ALSO         top

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

AUTHOR         top

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

COLOPHON         top

       This page is part of the ncurses (new curses) project.  Information
       about the project can be found at 
       ⟨⟩.  If you have a
       bug report for this manual page, send it to  This page was obtained from the
       project's upstream Git mirror of the CVS repository
       ⟨git://⟩ on 2020-09-18.  (At that
       time, the date of the most recent commit that was found in the repos‐
       itory was 2020-08-17.)  If you discover any rendering problems in
       this HTML version of the page, or you believe there is a better or
       more up-to-date source for the page, or you have corrections or
       improvements to the information in this COLOPHON (which is not part
       of the original manual page), send a mail to