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).
+
+
+
+ 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.
+
- Most of the work is done by the inner function
+
+ 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
+ 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-
+ 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.
+
+ 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.
-
-
RETURN VALUE
- Except as notes, these function return the integer ERR
- upon failure and OK on success. They will fail if either
+
+
+ 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 real-
- loc may have been interrupted, since it uses those func-
+ 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 ncurses is configured to supply its own SIGWINCH han-
+ dler,
+
+ 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 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
@@ -116,13 +135,24 @@
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
-
-
AUTHOR
+ 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).
+
+
+