- This is an extension to the curses library. It provides
- callers with a hook into the ncurses data to resize win-
- dows, 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 dimen-
- sions, and adjusts other bookkeeping data used by the
- ncurses library that record the window dimensions.
-
- Most of the work is done by the inner function
- resize_term. The outer function resizeterm adds bookkeep-
- ing 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 appro-
- priate 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 addi-
- tional 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 win-
- dows would be modified, and FALSE otherwise.
+
+ 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).
-
-
RETURN VALUE
- Except as notes, these function 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.
+
+ 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.
-
-
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 real-
- loc may have been interrupted, since it uses those func-
- tions.
-
- If ncurses is configured to supply its own SIGWINCH han-
- dler, the resizeterm function ungetch's a KEY_RESIZE which
- will be read on the next call to getch. This is used to
- alert an application that the screen size has changed, and
- that it should repaint special features such as pads that
- cannot be done automatically.
-
- 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 SIG-
- WINCH is received, no screen size change may be recorded.
- In that case, no KEY_RESIZE is queued for the next call to
- getch; an ERR will be returned instead.
+
+ 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.
-
-
SEE ALSO
- curs_variables(3x), wresize(3x).
+ 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.
-
-
AUTHOR
- Thomas Dickey (from an equivalent function written in 1988
- for BSD curses).
+
+
+ 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,
+
+ 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.
+
+
+
+ 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).
+
+
+