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28 ****************************************************************************
29 * Author: Thomas E. Dickey 1996-on
30 * @Id: resizeterm.3x,v 1.24 2017/11/18 23:47:37 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 curses terminal
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 callers with a
64 hook into the <STRONG>ncurses</STRONG> data to resize windows, primarily for use by pro-
65 grams running in an X Window terminal (e.g., xterm).
68 </PRE><H3><a name="h3-resizeterm">resizeterm</a></H3><PRE>
69 The function <STRONG>resizeterm</STRONG> resizes the standard and current windows to the
70 specified dimensions, and adjusts other bookkeeping data used by the
71 <STRONG>ncurses</STRONG> library that record the window dimensions such as the <STRONG>LINES</STRONG> and
72 <STRONG>COLS</STRONG> variables.
75 </PRE><H3><a name="h3-resize_term">resize_term</a></H3><PRE>
76 Most of the work is done by the inner function <STRONG>resize_term</STRONG>. The outer
77 function <STRONG>resizeterm</STRONG> adds bookkeeping for the <STRONG>SIGWINCH</STRONG> handler. When
78 resizing the windows, <STRONG>resize_term</STRONG> blank-fills the areas that are
79 extended. The calling application should fill in these areas with
80 appropriate data. The <STRONG>resize_term</STRONG> function attempts to resize all win-
81 dows. However, due to the calling convention of pads, it is not possi-
82 ble to resize these without additional interaction with the applica-
86 </PRE><H3><a name="h3-is_term_resized">is_term_resized</a></H3><PRE>
87 A support function <STRONG>is_term_resized</STRONG> is provided so that applications can
88 check if the <STRONG>resize_term</STRONG> function would modify the window structures.
89 It returns <STRONG>TRUE</STRONG> if the windows would be modified, and <STRONG>FALSE</STRONG> otherwise.
92 </PRE><H2><a name="h2-RETURN-VALUE">RETURN VALUE</a></H2><PRE>
93 Except as noted, these functions return the integer <STRONG>ERR</STRONG> upon failure
94 and <STRONG>OK</STRONG> on success. They will fail if either of the dimensions are less
95 than or equal to zero, or if an error occurs while (re)allocating mem-
99 </PRE><H2><a name="h2-NOTES">NOTES</a></H2><PRE>
100 While these functions are intended to be used to support a signal han-
101 dler (i.e., for <STRONG>SIGWINCH</STRONG>), care should be taken to avoid invoking them
102 in a context where <STRONG>malloc</STRONG> or <STRONG>realloc</STRONG> may have been interrupted, since
103 it uses those functions.
105 If ncurses is configured to supply its own <STRONG>SIGWINCH</STRONG> handler,
107 <STRONG>o</STRONG> on receipt of a <STRONG>SIGWINCH</STRONG>, the handler sets a flag
109 <STRONG>o</STRONG> which is tested in <STRONG><A HREF="curs_getch.3x.html">wgetch(3x)</A></STRONG> and <STRONG>doupdate</STRONG>,
111 <STRONG>o</STRONG> in turn, calling the <STRONG>resizeterm</STRONG> function,
113 <STRONG>o</STRONG> which <STRONG>ungetch</STRONG>'s a <STRONG>KEY_RESIZE</STRONG> which will be read on the next call to
114 <STRONG>wgetch</STRONG>.
116 The <STRONG>KEY_RESIZE</STRONG> alerts an application that the screen size has
117 changed, and that it should repaint special features such as pads
118 that cannot be done automatically.
120 Calling <STRONG>resizeterm</STRONG> or <STRONG>resize_term</STRONG> directly from a signal handler is
121 unsafe. This indirect method is used to provide a safe way to
122 resize the ncurses data structures.
124 If the environment variables <STRONG>LINES</STRONG> or <STRONG>COLUMNS</STRONG> are set, this overrides
125 the library's use of the window size obtained from the operating sys-
126 tem. Thus, even if a <STRONG>SIGWINCH</STRONG> is received, no screen size change may
130 </PRE><H2><a name="h2-PORTABILITY">PORTABILITY</a></H2><PRE>
131 It is possible to resize the screen with SVr4 curses, by
133 <STRONG>o</STRONG> exiting curses with <STRONG><A HREF="curs_initscr.3x.html">endwin(3x)</A></STRONG> and
135 <STRONG>o</STRONG> resuming using <STRONG><A HREF="curs_refresh.3x.html">refresh(3x)</A></STRONG>.
137 Doing that clears the screen and is visually distracting.
139 This extension of ncurses was introduced in mid-1995. It was adopted
140 in NetBSD curses (2001) and PDCurses (2003).
143 </PRE><H2><a name="h2-SEE-ALSO">SEE ALSO</a></H2><PRE>
144 <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>.
147 </PRE><H2><a name="h2-AUTHOR">AUTHOR</a></H2><PRE>
148 Thomas Dickey (from an equivalent function written in 1988 for BSD
153 <STRONG><A HREF="resizeterm.3x.html">resizeterm(3x)</A></STRONG>
157 <li><a href="#h2-NAME">NAME</a></li>
158 <li><a href="#h2-SYNOPSIS">SYNOPSIS</a></li>
159 <li><a href="#h2-DESCRIPTION">DESCRIPTION</a>
161 <li><a href="#h3-resizeterm">resizeterm</a></li>
162 <li><a href="#h3-resize_term">resize_term</a></li>
163 <li><a href="#h3-is_term_resized">is_term_resized</a></li>
166 <li><a href="#h2-RETURN-VALUE">RETURN VALUE</a></li>
167 <li><a href="#h2-NOTES">NOTES</a></li>
168 <li><a href="#h2-PORTABILITY">PORTABILITY</a></li>
169 <li><a href="#h2-SEE-ALSO">SEE ALSO</a></li>
170 <li><a href="#h2-AUTHOR">AUTHOR</a></li>