+ 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.
+ terminal (e.g., xterm).
- When resizing the windows, the function blank-fills the
- areas that are extended. The calling application should
- fill in these areas with appropriate data.
- The 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.
+
+ 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 vari-
+ ables.
-
-
RETURN VALUE
- The function returns the integer ERR upon failure and OK
- on success. It will fail if either of the dimensions less
- than or equal to zero, or if an error occurs while
- (re)allocating memory for the windows.
+
+ 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.
-
-
NOTES
- While this function is intended to be used to support a
+
+ 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.
+
+
+
+ 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 it in a context where malloc or realloc
- may have been interrupted, since it uses those functions.
+ 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.
+ dler,
+ o on receipt of a SIGWINCH, the handler sets a flag
-
-
SEE ALSO
- wresize(3x).
+ o which is tested in wgetch and doupdate,
+ o in turn, calling the resizeterm function,
-
-
AUTHOR
+ 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 automati-
+ cally.
+
+ Calling resizeterm or resize_term directly from a sig-
+ nal 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 SIG-
+ WINCH 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).
+
+
+