* authorization. *
****************************************************************************
* Author: Thomas E. Dickey 1996-on
- * @Id: resizeterm.3x,v 1.18 2015/04/11 10:23:49 tom Exp @
+ * @Id: resizeterm.3x,v 1.21 2015/09/26 19:55:32 tom Exp @
-->
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01//EN">
<HTML>
-</PRE>
-<H2><a name="h2-NAME">NAME</a></H2><PRE>
+</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-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>resizeterm(int</STRONG> <STRONG>lines,</STRONG> <STRONG>int</STRONG> <STRONG>columns);</STRONG>
-</PRE>
-<H2><a name="h2-DESCRIPTION">DESCRIPTION</a></H2><PRE>
+</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). The function <STRONG>resizeterm</STRONG> resizes
- the standard and current windows to the specified dimen-
- sions, 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> variables.
+ terminal (e.g., xterm).
+
+</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.
+
+
+</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,
pads, it is not possible to resize these without addi-
tional interaction with the application.
+
+</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.
-</PRE>
-<H2><a name="h2-RETURN-VALUE">RETURN VALUE</a></H2><PRE>
+</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>
+</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>
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-
+ dler,
+
+ <STRONG>o</STRONG> on receipt of a SIGWINCH, the handler sets a flag
+
+ <STRONG>o</STRONG> which is tested in <STRONG>wgetch</STRONG> and <STRONG>doupdate</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 automati-
+ cally.
+
+ Calling <STRONG>resizeterm</STRONG> or <STRONG>resize_term</STRONG> 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 <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-SEE-ALSO">SEE ALSO</a></H2><PRE>
+</PRE><H2><a name="h2-PORTABILITY">PORTABILITY</a></H2><PRE>
+ It is possible to resize the screen with SVr4 curses, by
+
+ <STRONG>o</STRONG> exiting curses with <STRONG><A HREF="endwin.3x.html">endwin(3x)</A></STRONG> and
+
+ <STRONG>o</STRONG> resuming using <STRONG><A HREF="refresh.3x.html">refresh(3x)</A></STRONG>.
+
+ 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).
+
+
+</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>
-<H2><a name="h2-AUTHOR">AUTHOR</a></H2><PRE>
+</PRE><H2><a name="h2-AUTHOR">AUTHOR</a></H2><PRE>
Thomas Dickey (from an equivalent function written in 1988
for BSD curses).
<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>
+<li><a href="#h2-DESCRIPTION">DESCRIPTION</a>
+<ul>
+<li><a href="#h3-resizeterm">resizeterm</a></li>
+<li><a href="#h3-resize_term">resize_term</a></li>
+<li><a href="#h3-is_term_resized">is_term_resized</a></li>
+</ul>
+</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-SEE-ALSO">SEE ALSO</a></li>
<li><a href="#h2-AUTHOR">AUTHOR</a></li>
</ul>