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+ * Copyright 2018-2023,2024 Thomas E. Dickey *
+ * Copyright 1998-2015,2017 Free Software Foundation, Inc. *
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* Author: Thomas E. Dickey 1996-on
- * @Id: resizeterm.3x,v 1.19 2015/06/06 23:38:18 tom Exp @
+ * @Id: resizeterm.3x,v 1.56 2024/03/16 15:35:01 tom Exp @
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-<H1 class="no-header">resizeterm 3x</H1>
+<H1 class="no-header">resizeterm 3x 2024-03-16 ncurses 6.4 Library calls</H1>
<PRE>
-<STRONG><A HREF="resizeterm.3x.html">resizeterm(3x)</A></STRONG>
<STRONG><A HREF="resizeterm.3x.html">resizeterm(3x)</A></STRONG>
+<STRONG><A HREF="resizeterm.3x.html">resizeterm(3x)</A></STRONG>
Library calls <STRONG><A HREF="resizeterm.3x.html">resizeterm(3x)</A></STRONG>
-</PRE>
-<H2><a name="h2-NAME">NAME</a></H2><PRE>
- <STRONG>is_term_resized</STRONG>, <STRONG>resize_term</STRONG>, <STRONG>resizeterm</STRONG> - change the
- curses terminal size
+</PRE><H2><a name="h2-NAME">NAME</a></H2><PRE>
+ <STRONG>is_term_resized</STRONG>, <STRONG>resize_term</STRONG>, <STRONG>resizeterm</STRONG> - manage the terminal
+ dimensions understood by <EM>curses</EM>
-</PRE>
-<H2><a name="h2-SYNOPSIS">SYNOPSIS</a></H2><PRE>
+</PRE><H2><a name="h2-SYNOPSIS">SYNOPSIS</a></H2><PRE>
<STRONG>#include</STRONG> <STRONG><curses.h></STRONG>
- <STRONG>bool</STRONG> <STRONG>is_term_resized(int</STRONG> <STRONG>lines,</STRONG> <STRONG>int</STRONG> <STRONG>columns);</STRONG>
- <STRONG>int</STRONG> <STRONG>resize_term(int</STRONG> <STRONG>lines,</STRONG> <STRONG>int</STRONG> <STRONG>columns);</STRONG>
- <STRONG>int</STRONG> <STRONG>resizeterm(int</STRONG> <STRONG>lines,</STRONG> <STRONG>int</STRONG> <STRONG>columns);</STRONG>
+ <STRONG>bool</STRONG> <STRONG>is_term_resized(int</STRONG> <EM>lines</EM><STRONG>,</STRONG> <STRONG>int</STRONG> <EM>columns</EM><STRONG>);</STRONG>
+ <STRONG>int</STRONG> <STRONG>resize_term(int</STRONG> <EM>lines</EM><STRONG>,</STRONG> <STRONG>int</STRONG> <EM>columns</EM><STRONG>);</STRONG>
+ <STRONG>int</STRONG> <STRONG>resizeterm(int</STRONG> <EM>lines</EM><STRONG>,</STRONG> <STRONG>int</STRONG> <EM>columns</EM><STRONG>);</STRONG>
-</PRE>
-<H2><a name="h2-DESCRIPTION">DESCRIPTION</a></H2><PRE>
- This is an extension to the curses library. It provides
- callers with a hook into the <STRONG>ncurses</STRONG> data to resize win-
- dows, primarily for use by programs running in an X Window
- terminal (e.g., xterm).
+</PRE><H2><a name="h2-DESCRIPTION">DESCRIPTION</a></H2><PRE>
+ This is an extension to the <EM>curses</EM> library. It provides callers with a
+ hook into the <EM>ncurses</EM> data to resize windows, primarily for use by
+ programs running in an X Window terminal (e.g., xterm) when the
+ terminal's screen size is changed by the user:
+ <STRONG>o</STRONG> <EM>curses</EM> windows cannot extend outside the screen. If the terminal
+ is shrunk, <EM>curses</EM> windows must be shrunk to fit.
-</PRE>
-<H3><a name="h3-resizeterm">resizeterm</a></H3><PRE>
- The function <STRONG>resizeterm</STRONG> resizes the standard and current
- windows to the specified dimensions, and adjusts other
- bookkeeping data used by the <STRONG>ncurses</STRONG> library that record
- the window dimensions such as the <STRONG>LINES</STRONG> and <STRONG>COLS</STRONG> vari-
- ables.
+ <STRONG>o</STRONG> If the terminal is stretched, rows and/or columns can be added to
+ existing windows. The added cells should match the current
+ attributes of the windows.
+ If the calling program has not set up a handler for <STRONG>SIGWINCH</STRONG> when it
+ initializes <EM>ncurses</EM> (e.g., using <STRONG><A HREF="curs_initscr.3x.html">initscr(3x)</A></STRONG> or <STRONG><A HREF="curs_initscr.3x.html">newterm(3x)</A></STRONG>), then
+ <EM>ncurses</EM> sets a handler for <STRONG>SIGWINCH</STRONG> which notifies the library when a
+ window-size event has occurred. The library checks for this
+ notification
-</PRE>
-<H3><a name="h3-resize_term">resize_term</a></H3><PRE>
- Most of the work is done by the inner function
- <STRONG>resize_term</STRONG>. The outer function <STRONG>resizeterm</STRONG> adds bookkeep-
- ing for the SIGWINCH handler. When resizing the windows,
- <STRONG>resize_term</STRONG> blank-fills the areas that are extended. The
- calling application should fill in these areas with appro-
- priate data. The <STRONG>resize_term</STRONG> 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.
+ <STRONG>o</STRONG> when reading input data,
+ <STRONG>o</STRONG> when implicitly resuming program mode (e.g., between <STRONG><A HREF="curs_initscr.3x.html">endwin(3x)</A></STRONG> and
+ <STRONG><A HREF="curs_refresh.3x.html">wrefresh(3x)</A></STRONG>), and
-</PRE>
-<H3><a name="h3-is_term_resized">is_term_resized</a></H3><PRE>
- A support function <STRONG>is_term_resized</STRONG> is provided so that
- applications can check if the <STRONG>resize_term</STRONG> function would
- modify the window structures. It returns <STRONG>TRUE</STRONG> if the win-
- dows would be modified, and <STRONG>FALSE</STRONG> otherwise.
+ <STRONG>o</STRONG> when explicitly resuming program mode in <STRONG><A HREF="curs_terminfo.3x.html">restartterm(3x)</A></STRONG>.
+ When the library has found that the terminal's window-size has changed,
+ it calls <STRONG>resizeterm</STRONG> to update its data structures.
-</PRE>
-<H2><a name="h2-RETURN-VALUE">RETURN VALUE</a></H2><PRE>
- Except as noted, these functions return the integer <STRONG>ERR</STRONG>
- upon failure and <STRONG>OK</STRONG> 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.
+ An application which establishes its own <STRONG>SIGWINCH</STRONG> handler can call
+ <STRONG>resizeterm</STRONG>, but in that case, the library will not see <STRONG>SIGWINCH</STRONG>, and
+ proper layout will rely upon the application.
-</PRE>
-<H2><a name="h2-NOTES">NOTES</a></H2><PRE>
- 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 <STRONG>malloc</STRONG> or <STRONG>real-</STRONG>
- <STRONG>loc</STRONG> may have been interrupted, since it uses those func-
- tions.
-
- If ncurses is configured to supply its own SIGWINCH han-
- dler, the <STRONG>resizeterm</STRONG> function <STRONG>ungetch</STRONG>'s a <STRONG>KEY_RESIZE</STRONG> which
- will be read on the next call to <STRONG>getch</STRONG>. 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 <STRONG>LINES</STRONG> or <STRONG>COLUMNS</STRONG> 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.
+</PRE><H2><a name="h2-FUNCTIONS">FUNCTIONS</a></H2><PRE>
+</PRE><H3><a name="h3-resizeterm">resizeterm</a></H3><PRE>
+ The function <STRONG>resizeterm</STRONG> resizes the standard and current windows (i.e.,
+ <STRONG>stdscr</STRONG> and <STRONG>curscr</STRONG>) to the specified dimensions, and adjusts other
+ bookkeeping data used by the <EM>ncurses</EM> library that record the window
+ dimensions such as the <STRONG>LINES</STRONG> and <STRONG>COLS</STRONG> variables.
-</PRE>
-<H2><a name="h2-SEE-ALSO">SEE ALSO</a></H2><PRE>
- <STRONG><A HREF="curs_getch.3x.html">curs_getch(3x)</A></STRONG>, <STRONG><A HREF="curs_variables.3x.html">curs_variables(3x)</A></STRONG>, <STRONG><A HREF="wresize.3x.html">wresize(3x)</A></STRONG>.
+</PRE><H3><a name="h3-resize_term">resize_term</a></H3><PRE>
+ Most of the work for <STRONG>resizeterm</STRONG> is done by the inner function
+ <STRONG>resize_term</STRONG>. The outer function <STRONG>resizeterm</STRONG> adds bookkeeping for the
+ <STRONG>SIGWINCH</STRONG> handler, as well as repainting the soft-key area (see
+ <STRONG><A HREF="curs_slk.3x.html">slk_touch(3x)</A></STRONG>).
-</PRE>
-<H2><a name="h2-AUTHOR">AUTHOR</a></H2><PRE>
- Thomas Dickey (from an equivalent function written in 1988
- for BSD curses).
+ The <STRONG>resize_term</STRONG> function attempts to resize all windows. This helps
+ with simple applications. However:
+
+ <STRONG>o</STRONG> It is not possible to automatically resize pads.
+
+ <STRONG>o</STRONG> Applications which have complicated layouts should check for
+ <STRONG>KEY_RESIZE</STRONG> returned from <STRONG>wgetch</STRONG>, and adjust their layout, e.g.,
+ using <STRONG>wresize</STRONG> and <STRONG>mvwin</STRONG>, or by recreating the windows.
+
+ When resizing windows, <STRONG>resize_term</STRONG> 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, <STRONG>resize_term</STRONG> will keep the window extending to the corresponding
+ limit, regardless of whether the screen has shrunk or grown.
+
+
+</PRE><H3><a name="h3-is_term_resized">is_term_resized</a></H3><PRE>
+ A support function <STRONG>is_term_resized</STRONG> is provided so that applications can
+ check if the <STRONG>resize_term</STRONG> function would modify the window structures.
+ It returns <STRONG>TRUE</STRONG> if the windows would be modified, and <STRONG>FALSE</STRONG> otherwise.
+
+
+</PRE><H2><a name="h2-RETURN-VALUE">RETURN VALUE</a></H2><PRE>
+ Except as noted, these functions return the integer <STRONG>ERR</STRONG> upon failure
+ and <STRONG>OK</STRONG> 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.
+
+
+</PRE><H2><a name="h2-NOTES">NOTES</a></H2><PRE>
+ While these functions are intended to be used to support a signal
+ handler (i.e., for <STRONG>SIGWINCH</STRONG>), care should be taken to avoid invoking
+ them in a context where <STRONG>malloc</STRONG> or <STRONG>realloc</STRONG> may have been interrupted,
+ since it uses those functions.
+
+ If <EM>ncurses</EM> is configured to supply its own <STRONG>SIGWINCH</STRONG> handler,
+
+ <STRONG>o</STRONG> on receipt of a <STRONG>SIGWINCH</STRONG>, the handler sets a flag
+
+ <STRONG>o</STRONG> which is tested in <STRONG><A HREF="curs_getch.3x.html">wgetch(3x)</A></STRONG>, <STRONG><A HREF="curs_refresh.3x.html">doupdate(3x)</A></STRONG> and <STRONG><A HREF="curs_terminfo.3x.html">restartterm(3x)</A></STRONG>,
+
+ <STRONG>o</STRONG> in turn, calling the <STRONG>resizeterm</STRONG> function,
+
+ <STRONG>o</STRONG> which <STRONG>ungetch</STRONG>'s a <STRONG>KEY_RESIZE</STRONG> which will be read on the next call to
+ <STRONG>wgetch</STRONG>.
+
+ The <STRONG>KEY_RESIZE</STRONG> 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 <STRONG>resizeterm</STRONG> or <STRONG>resize_term</STRONG> directly from a signal handler is
+ unsafe. This indirect method is used to provide a safe way to
+ resize the <EM>ncurses</EM> data structures.
+
+ If the environment variables <EM>LINES</EM> or <EM>COLUMNS</EM> are set, this overrides
+ the library's use of the window size obtained from the operating
+ system. Thus, even if a <STRONG>SIGWINCH</STRONG> is received, no screen size change
+ may be recorded.
+
+
+</PRE><H2><a name="h2-PORTABILITY">PORTABILITY</a></H2><PRE>
+ It is possible to resize the screen with SVr4 <EM>curses</EM>, by
+
+ <STRONG>o</STRONG> exiting <EM>curses</EM> with <STRONG><A HREF="curs_initscr.3x.html">endwin(3x)</A></STRONG> and
+
+ <STRONG>o</STRONG> resuming using <STRONG><A HREF="curs_refresh.3x.html">refresh(3x)</A></STRONG>.
+
+ Doing that clears the screen and is visually distracting.
+
+ This extension of <EM>ncurses</EM> was introduced in mid-1995. It was adopted
+ in NetBSD <EM>curses</EM> (2001) and PDCurses (2003).
+
+
+</PRE><H2><a name="h2-AUTHORS">AUTHORS</a></H2><PRE>
+ Thomas Dickey (from an equivalent function written in 1988 for BSD
+ <EM>curses</EM>)
+
+
+</PRE><H2><a name="h2-SEE-ALSO">SEE ALSO</a></H2><PRE>
+ <STRONG><A HREF="curs_getch.3x.html">curs_getch(3x)</A></STRONG>, <STRONG><A HREF="curs_variables.3x.html">curs_variables(3x)</A></STRONG>, <STRONG><A HREF="wresize.3x.html">wresize(3x)</A></STRONG>
-
<STRONG><A HREF="resizeterm.3x.html">resizeterm(3x)</A></STRONG>
+
ncurses 6.4 2024-03-16 <STRONG><A HREF="resizeterm.3x.html">resizeterm(3x)</A></STRONG>
</PRE>
<div class="nav">
<ul>
<li><a href="#h2-NAME">NAME</a></li>
<li><a href="#h2-SYNOPSIS">SYNOPSIS</a></li>
-<li><a href="#h2-DESCRIPTION">DESCRIPTION</a>
+<li><a href="#h2-DESCRIPTION">DESCRIPTION</a></li>
+<li><a href="#h2-FUNCTIONS">FUNCTIONS</a>
<ul>
<li><a href="#h3-resizeterm">resizeterm</a></li>
<li><a href="#h3-resize_term">resize_term</a></li>
</li>
<li><a href="#h2-RETURN-VALUE">RETURN VALUE</a></li>
<li><a href="#h2-NOTES">NOTES</a></li>
+<li><a href="#h2-PORTABILITY">PORTABILITY</a></li>
+<li><a href="#h2-AUTHORS">AUTHORS</a></li>
<li><a href="#h2-SEE-ALSO">SEE ALSO</a></li>
-<li><a href="#h2-AUTHOR">AUTHOR</a></li>
</ul>
</div>
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