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| <H1 class="no-header">resizeterm 3x 2024-03-16 ncurses 6.5 Library calls</H1> |
| <PRE> |
| <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> - manage the terminal |
| dimensions understood by <EM>curses</EM> |
| |
| |
| </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> <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 <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. |
| |
| <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 |
| |
| <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 |
| |
| <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. |
| |
| 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-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><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>). |
| |
| 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> |
| |
| |
| |
| ncurses 6.5 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> |
| <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><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-AUTHORS">AUTHORS</a></li> |
| <li><a href="#h2-SEE-ALSO">SEE ALSO</a></li> |
| </ul> |
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