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29 * Author: Thomas E. Dickey 1996-on
30 * @Id: resizeterm.3x,v 1.21 2015/09/26 19:55:32 tom Exp @
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42 <H1 class="no-header">resizeterm 3x</H1>
44 <STRONG><A HREF="resizeterm.3x.html">resizeterm(3x)</A></STRONG> <STRONG><A HREF="resizeterm.3x.html">resizeterm(3x)</A></STRONG>
49 </PRE><H2><a name="h2-NAME">NAME</a></H2><PRE>
50 <STRONG>is_term_resized</STRONG>, <STRONG>resize_term</STRONG>, <STRONG>resizeterm</STRONG> - change the
54 </PRE><H2><a name="h2-SYNOPSIS">SYNOPSIS</a></H2><PRE>
55 <STRONG>#include</STRONG> <STRONG><curses.h></STRONG>
57 <STRONG>bool</STRONG> <STRONG>is_term_resized(int</STRONG> <STRONG>lines,</STRONG> <STRONG>int</STRONG> <STRONG>columns);</STRONG>
58 <STRONG>int</STRONG> <STRONG>resize_term(int</STRONG> <STRONG>lines,</STRONG> <STRONG>int</STRONG> <STRONG>columns);</STRONG>
59 <STRONG>int</STRONG> <STRONG>resizeterm(int</STRONG> <STRONG>lines,</STRONG> <STRONG>int</STRONG> <STRONG>columns);</STRONG>
62 </PRE><H2><a name="h2-DESCRIPTION">DESCRIPTION</a></H2><PRE>
63 This is an extension to the curses library. It provides
64 callers with a hook into the <STRONG>ncurses</STRONG> data to resize win-
65 dows, primarily for use by programs running in an X Window
66 terminal (e.g., xterm).
69 </PRE><H3><a name="h3-resizeterm">resizeterm</a></H3><PRE>
70 The function <STRONG>resizeterm</STRONG> resizes the standard and current
71 windows to the specified dimensions, and adjusts other
72 bookkeeping data used by the <STRONG>ncurses</STRONG> library that record
73 the window dimensions such as the <STRONG>LINES</STRONG> and <STRONG>COLS</STRONG> vari-
77 </PRE><H3><a name="h3-resize_term">resize_term</a></H3><PRE>
78 Most of the work is done by the inner function
79 <STRONG>resize_term</STRONG>. The outer function <STRONG>resizeterm</STRONG> adds bookkeep-
80 ing for the SIGWINCH handler. When resizing the windows,
81 <STRONG>resize_term</STRONG> blank-fills the areas that are extended. The
82 calling application should fill in these areas with appro-
83 priate data. The <STRONG>resize_term</STRONG> function attempts to resize
84 all windows. However, due to the calling convention of
85 pads, it is not possible to resize these without addi-
86 tional interaction with the application.
89 </PRE><H3><a name="h3-is_term_resized">is_term_resized</a></H3><PRE>
90 A support function <STRONG>is_term_resized</STRONG> is provided so that
91 applications can check if the <STRONG>resize_term</STRONG> function would
92 modify the window structures. It returns <STRONG>TRUE</STRONG> if the win-
93 dows would be modified, and <STRONG>FALSE</STRONG> otherwise.
96 </PRE><H2><a name="h2-RETURN-VALUE">RETURN VALUE</a></H2><PRE>
97 Except as noted, these functions return the integer <STRONG>ERR</STRONG>
98 upon failure and <STRONG>OK</STRONG> on success. They will fail if either
99 of the dimensions are less than or equal to zero, or if an
100 error occurs while (re)allocating memory for the windows.
103 </PRE><H2><a name="h2-NOTES">NOTES</a></H2><PRE>
104 While these functions are intended to be used to support a
105 signal handler (i.e., for SIGWINCH), care should be taken
106 to avoid invoking them in a context where <STRONG>malloc</STRONG> or <STRONG>real-</STRONG>
107 <STRONG>loc</STRONG> may have been interrupted, since it uses those func-
110 If ncurses is configured to supply its own SIGWINCH han-
113 <STRONG>o</STRONG> on receipt of a SIGWINCH, the handler sets a flag
115 <STRONG>o</STRONG> which is tested in <STRONG>wgetch</STRONG> and <STRONG>doupdate</STRONG>,
117 <STRONG>o</STRONG> in turn, calling the <STRONG>resizeterm</STRONG> function,
119 <STRONG>o</STRONG> which <STRONG>ungetch</STRONG>'s a <STRONG>KEY_RESIZE</STRONG> which will be read on the
120 next call to <STRONG>wgetch</STRONG>.
122 The <STRONG>KEY_RESIZE</STRONG> alerts an application that the screen
123 size has changed, and that it should repaint special
124 features such as pads that cannot be done automati-
127 Calling <STRONG>resizeterm</STRONG> or <STRONG>resize_term</STRONG> directly from a sig-
128 nal handler is unsafe. This indirect method is used
129 to provide a safe way to resize the ncurses data
132 If the environment variables <STRONG>LINES</STRONG> or <STRONG>COLUMNS</STRONG> are set,
133 this overrides the library's use of the window size
134 obtained from the operating system. Thus, even if a SIG-
135 WINCH is received, no screen size change may be recorded.
138 </PRE><H2><a name="h2-PORTABILITY">PORTABILITY</a></H2><PRE>
139 It is possible to resize the screen with SVr4 curses, by
141 <STRONG>o</STRONG> exiting curses with <STRONG><A HREF="endwin.3x.html">endwin(3x)</A></STRONG> and
143 <STRONG>o</STRONG> resuming using <STRONG><A HREF="refresh.3x.html">refresh(3x)</A></STRONG>.
145 Doing that clears the screen and is visually distracting.
147 This extension of ncurses was introduced in mid-1995. It
148 was adopted in NetBSD curses (2001) and PDCurses (2003).
151 </PRE><H2><a name="h2-SEE-ALSO">SEE ALSO</a></H2><PRE>
152 <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>.
155 </PRE><H2><a name="h2-AUTHOR">AUTHOR</a></H2><PRE>
156 Thomas Dickey (from an equivalent function written in 1988
161 <STRONG><A HREF="resizeterm.3x.html">resizeterm(3x)</A></STRONG>
165 <li><a href="#h2-NAME">NAME</a></li>
166 <li><a href="#h2-SYNOPSIS">SYNOPSIS</a></li>
167 <li><a href="#h2-DESCRIPTION">DESCRIPTION</a>
169 <li><a href="#h3-resizeterm">resizeterm</a></li>
170 <li><a href="#h3-resize_term">resize_term</a></li>
171 <li><a href="#h3-is_term_resized">is_term_resized</a></li>
174 <li><a href="#h2-RETURN-VALUE">RETURN VALUE</a></li>
175 <li><a href="#h2-NOTES">NOTES</a></li>
176 <li><a href="#h2-PORTABILITY">PORTABILITY</a></li>
177 <li><a href="#h2-SEE-ALSO">SEE ALSO</a></li>
178 <li><a href="#h2-AUTHOR">AUTHOR</a></li>