* sale, use or other dealings in this Software without prior written *
* authorization. *
****************************************************************************
- * @Id: curs_initscr.3x,v 1.45 2023/08/19 19:46:20 tom Exp @
+ * @Id: curs_initscr.3x,v 1.50 2023/09/16 23:37:03 tom Exp @
-->
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01//EN">
<HTML>
<HEAD>
<meta http-equiv="Content-Type" content="text/html; charset=us-ascii">
<meta name="generator" content="Manpage converted by man2html - see https://invisible-island.net/scripts/readme.html#others_scripts">
-<TITLE>curs_initscr 3x 2023-08-19 ncurses 6.4 Library calls</TITLE>
+<TITLE>curs_initscr 3x 2023-09-16 ncurses 6.4 Library calls</TITLE>
<link rel="author" href="mailto:bug-ncurses@gnu.org">
</HEAD>
<BODY>
-<H1 class="no-header">curs_initscr 3x 2023-08-19 ncurses 6.4 Library calls</H1>
+<H1 class="no-header">curs_initscr 3x 2023-09-16 ncurses 6.4 Library calls</H1>
<PRE>
<STRONG><A HREF="curs_initscr.3x.html">curs_initscr(3x)</A></STRONG> Library calls <STRONG><A HREF="curs_initscr.3x.html">curs_initscr(3x)</A></STRONG>
</PRE><H2><a name="h2-NAME">NAME</a></H2><PRE>
- <STRONG>initscr</STRONG>, <STRONG>newterm</STRONG>, <STRONG>endwin</STRONG>, <STRONG>isendwin</STRONG>, <STRONG>set_term</STRONG>, <STRONG>delscreen</STRONG> - <STRONG>curses</STRONG> screen
- initialization and manipulation routines
+ <STRONG>initscr</STRONG>, <STRONG>newterm</STRONG>, <STRONG>endwin</STRONG>, <STRONG>isendwin</STRONG>, <STRONG>set_term</STRONG>, <STRONG>delscreen</STRONG> - initialize,
+ manipulate, or tear down <EM>curses</EM> terminal interface
</PRE><H2><a name="h2-SYNOPSIS">SYNOPSIS</a></H2><PRE>
it; these are <STRONG><A HREF="curs_slk.3x.html">slk_init(3x)</A></STRONG>, <STRONG>filter</STRONG>, <STRONG>ripoffline</STRONG>, <STRONG>use_env</STRONG>. For multiple-
terminal applications, <STRONG>newterm</STRONG> may be called before <STRONG>initscr</STRONG>.
- The initscr code determines the terminal type and initializes all <STRONG>curs-</STRONG>
- <STRONG>es</STRONG> data structures. <STRONG>initscr</STRONG> also causes the first call to <STRONG><A HREF="curscurs_refresh.3x.html">refresh(3x)</A></STRONG>
- to clear the screen. If errors occur, <STRONG>initscr</STRONG> writes an appropriate
- error message to standard error and exits; otherwise, a pointer is re-
- turned to <STRONG>stdscr</STRONG>.
+ The initscr code determines the terminal type and initializes all
+ <STRONG>curses</STRONG> data structures. <STRONG>initscr</STRONG> also causes the first call to
+ <STRONG><A HREF="curs_refresh.3x.html">refresh(3x)</A></STRONG> to clear the screen. If errors occur, <STRONG>initscr</STRONG> writes an
+ appropriate error message to standard error and exits; otherwise, a
+ pointer is returned to <STRONG>stdscr</STRONG>.
</PRE><H3><a name="h3-newterm">newterm</a></H3><PRE>
if the terminal cannot support a screen-oriented program, would also
use <STRONG>newterm</STRONG>.
- The routine <STRONG>newterm</STRONG> should be called once for each terminal. It re-
- turns a variable of type <STRONG>SCREEN</STRONG> <STRONG>*</STRONG> which should be saved as a reference
- to that terminal. <STRONG>newterm</STRONG>'s arguments are
+ The routine <STRONG>newterm</STRONG> should be called once for each terminal. It
+ returns a variable of type <STRONG>SCREEN</STRONG> <STRONG>*</STRONG> which should be saved as a
+ reference to that terminal. <STRONG>newterm</STRONG>'s arguments are
<STRONG>o</STRONG> the <EM>type</EM> of the terminal to be used in place of <STRONG>$TERM</STRONG>,
If the <EM>type</EM> parameter is <STRONG>NULL</STRONG>, <STRONG>$TERM</STRONG> will be used.
The file descriptor of the output stream is passed to <STRONG><A HREF="curs_terminfo.3x.html">setupterm(3x)</A></STRONG>,
- which returns a pointer to a <STRONG>TERMINAL</STRONG> structure. <STRONG>newterm</STRONG>'s return val-
- ue holds a pointer to the <STRONG>TERMINAL</STRONG> structure.
+ which returns a pointer to a <STRONG>TERMINAL</STRONG> structure. <STRONG>newterm</STRONG>'s return
+ value holds a pointer to the <STRONG>TERMINAL</STRONG> structure.
</PRE><H3><a name="h3-endwin">endwin</a></H3><PRE>
<STRONG>o</STRONG> moves the cursor to the lower left-hand corner of the screen,
- <STRONG>o</STRONG> clears the remainder of the line so that it uses the default col-
- ors,
+ <STRONG>o</STRONG> clears the remainder of the line so that it uses the default
+ colors,
<STRONG>o</STRONG> sets the cursor to normal visibility (see <STRONG><A HREF="curs_kernel.3x.html">curs_set(3x)</A></STRONG>),
- <STRONG>o</STRONG> stops cursor-addressing mode using the <EM>exit</EM><STRONG>_</STRONG><EM>ca</EM><STRONG>_</STRONG><EM>mode</EM> terminal capa-
- bility,
+ <STRONG>o</STRONG> stops cursor-addressing mode using the <EM>exit</EM><STRONG>_</STRONG><EM>ca</EM><STRONG>_</STRONG><EM>mode</EM> terminal
+ capability,
<STRONG>o</STRONG> restores tty modes (see <STRONG><A HREF="curs_kernel.3x.html">reset_shell_mode(3x)</A></STRONG>).
</PRE><H3><a name="h3-set_term">set_term</a></H3><PRE>
The <STRONG>set_term</STRONG> routine is used to switch between different terminals.
- The screen reference <EM>new</EM> becomes the new current terminal. The previ-
- ous terminal is returned by the routine. This is the only routine
+ The screen reference <EM>new</EM> becomes the new current terminal. The
+ previous terminal is returned by the routine. This is the only routine
which manipulates <STRONG>SCREEN</STRONG> pointers; all other routines affect only the
current terminal.
</PRE><H2><a name="h2-RETURN-VALUE">RETURN VALUE</a></H2><PRE>
- <STRONG>endwin</STRONG> returns the integer <STRONG>ERR</STRONG> upon failure and <STRONG>OK</STRONG> upon successful com-
- pletion.
+ <STRONG>endwin</STRONG> returns the integer <STRONG>ERR</STRONG> upon failure and <STRONG>OK</STRONG> upon successful
+ completion.
Routines that return pointers always return <STRONG>NULL</STRONG> on error.
<STRONG>newterm</STRONG>. Deleting a <STRONG>SCREEN</STRONG> provides a way to do this:
<STRONG>o</STRONG> X/Open Curses does not say what happens to <STRONG>WINDOW</STRONG>s when <STRONG>delscreen</STRONG>
- "frees storage associated with the <STRONG>SCREEN</STRONG>" nor does the SVr4 docu-
- mentation help, adding that it should be called after <STRONG>endwin</STRONG> if a
- <STRONG>SCREEN</STRONG> is no longer needed.
+ "frees storage associated with the <STRONG>SCREEN</STRONG>" nor does the SVr4
+ documentation help, adding that it should be called after <STRONG>endwin</STRONG> if
+ a <STRONG>SCREEN</STRONG> is no longer needed.
<STRONG>o</STRONG> However, <STRONG>WINDOW</STRONG>s are implicitly associated with a <STRONG>SCREEN</STRONG>. so that
it is reasonable to expect <STRONG>delscreen</STRONG> to deal with these.
<STRONG>curscr</STRONG> as well as a work area <STRONG>newscr</STRONG>. SVr4 curses ignores other
windows.
- <STRONG>o</STRONG> Since version 4.0 (1996), ncurses has maintained a list of all win-
- dows for each screen, using that information to delete those win-
- dows when <STRONG>delscreen</STRONG> is called.
+ <STRONG>o</STRONG> Since version 4.0 (1996), ncurses has maintained a list of all
+ windows for each screen, using that information to delete those
+ windows when <STRONG>delscreen</STRONG> is called.
<STRONG>o</STRONG> NetBSD copied this feature of ncurses in 2001. PDCurses follows
the SVr4 model, deleting only the standard <STRONG>WINDOW</STRONG> structures.
</PRE><H3><a name="h3-High-level-versus-low-level">High-level versus low-level</a></H3><PRE>
Different implementations may disagree regarding the level of some
- functions. For example, <STRONG>SCREEN</STRONG> (returned by <STRONG>newterm</STRONG>) and <STRONG>TERMINAL</STRONG> (re-
- turned by <STRONG><A HREF="curs_terminfo.3x.html">setupterm(3x)</A></STRONG>) hold file descriptors for the output stream.
- If an application switches screens using <STRONG>set_term</STRONG>, or switches termi-
- nals using <STRONG><A HREF="curs_terminfo.3x.html">set_curterm(3x)</A></STRONG>, applications which use the output file de-
- scriptor can have different behavior depending on which structure holds
- the corresponding descriptor.
+ functions. For example, <STRONG>SCREEN</STRONG> (returned by <STRONG>newterm</STRONG>) and <STRONG>TERMINAL</STRONG>
+ (returned by <STRONG><A HREF="curs_terminfo.3x.html">setupterm(3x)</A></STRONG>) hold file descriptors for the output
+ stream. If an application switches screens using <STRONG>set_term</STRONG>, or switches
+ terminals using <STRONG><A HREF="curs_terminfo.3x.html">set_curterm(3x)</A></STRONG>, applications which use the output file
+ descriptor can have different behavior depending on which structure
+ holds the corresponding descriptor.
For example
</PRE><H3><a name="h3-Unset-TERM-Variable">Unset TERM Variable</a></H3><PRE>
- If the TERM variable is missing or empty, <STRONG>initscr</STRONG> uses the value "un-
- known", which normally corresponds to a terminal entry with the <EM>generic</EM>
- (<EM>gn</EM>) capability. Generic entries are detected by <STRONG><A HREF="curs_terminfo.3x.html">setupterm(3x)</A></STRONG> and
- cannot be used for full-screen operation. Other implementations may
- handle a missing/empty TERM variable differently.
+ If the TERM variable is missing or empty, <STRONG>initscr</STRONG> uses the value
+ "unknown", which normally corresponds to a terminal entry with the
+ <EM>generic</EM> (<EM>gn</EM>) capability. Generic entries are detected by <STRONG><A HREF="curs_terminfo.3x.html">setupterm(3x)</A></STRONG>
+ and cannot be used for full-screen operation. Other implementations
+ may handle a missing/empty TERM variable differently.
</PRE><H3><a name="h3-Signal-Handlers">Signal Handlers</a></H3><PRE>
- Quoting from X/Open Curses, section 3.1.1:
+ Quoting from X/Open Curses Issue 7, section 3.1.1:
- <EM>Curses</EM> <EM>implementations</EM> <EM>may</EM> <EM>provide</EM> <EM>for</EM> <EM>special</EM> <EM>handling</EM> <EM>of</EM> <EM>the</EM>
- <STRONG>SIGINT</STRONG><EM>,</EM> <STRONG>SIGQUIT</STRONG> <EM>and</EM> <STRONG>SIGTSTP</STRONG> <EM>signals</EM> <EM>if</EM> <EM>their</EM> <EM>disposition</EM> <EM>is</EM>
- <STRONG>SIG_DFL</STRONG> <EM>at</EM> <EM>the</EM> <EM>time</EM> <STRONG>initscr</STRONG> <EM>is</EM> <EM>called</EM> ...
+ Curses implementations may provide for special handling of the
+ SIGINT, SIGQUIT, and SIGTSTP signals if their disposition is
+ SIG_DFL at the time <EM>initscr</EM> is called...
- <EM>Any</EM> <EM>special</EM> <EM>handling</EM> <EM>for</EM> <EM>these</EM> <EM>signals</EM> <EM>may</EM> <EM>remain</EM> <EM>in</EM> <EM>effect</EM> <EM>for</EM>
- <EM>the</EM> <EM>life</EM> <EM>of</EM> <EM>the</EM> <EM>process</EM> <EM>or</EM> <EM>until</EM> <EM>the</EM> <EM>process</EM> <EM>changes</EM> <EM>the</EM>
- <EM>disposition</EM> <EM>of</EM> <EM>the</EM> <EM>signal.</EM>
+ Any special handling for these signals may remain in effect for
+ the life of the process or until the process changes the
+ disposition of the signal.
- <EM>None</EM> <EM>of</EM> <EM>the</EM> <EM>Curses</EM> <EM>functions</EM> <EM>are</EM> <EM>required</EM> <EM>to</EM> <EM>be</EM> <EM>safe</EM> <EM>with</EM> <EM>respect</EM>
- <EM>to</EM> <EM>signals</EM> ...
+ None of the Curses functions are required to be safe with respect
+ to signals...
This implementation establishes signal handlers during initialization,
e.g., <STRONG>initscr</STRONG> or <STRONG>newterm</STRONG>. Applications which must handle these signals
- should set up the corresponding handlers <EM>after</EM> initializing the li-
- brary:
+ should set up the corresponding handlers <EM>after</EM> initializing the
+ library:
<STRONG>SIGINT</STRONG>
The handler <EM>attempts</EM> to cleanup the screen on exit. Although it
<STRONG>o</STRONG> Walking the <STRONG>SCREEN</STRONG> list is unsafe, since all list management
is done without any signal blocking.
- <STRONG>o</STRONG> On systems which have <STRONG>REENTRANT</STRONG> turned on, <STRONG>set_term</STRONG> uses func-
- tions which could deadlock or misbehave in other ways.
+ <STRONG>o</STRONG> On systems which have <STRONG>REENTRANT</STRONG> turned on, <STRONG>set_term</STRONG> uses
+ functions which could deadlock or misbehave in other ways.
<STRONG>o</STRONG> <STRONG>endwin</STRONG> calls other functions, many of which use stdio or other
library functions which are clearly unsafe.
<STRONG>SIGWINCH</STRONG>
This handles the window-size changes which were ignored in the
- standardization efforts. The handler sets a (signal-safe) vari-
- able which is later tested in <STRONG>wgetch</STRONG> (see <STRONG><A HREF="curs_getch.3x.html">curs_getch(3x)</A></STRONG>). If
- <STRONG>keypad</STRONG> has been enabled for the corresponding window, <STRONG>wgetch</STRONG> re-
- turns the key symbol <STRONG>KEY_RESIZE</STRONG>. At the same time, <STRONG>wgetch</STRONG> calls
+ standardization efforts. The handler sets a (signal-safe)
+ variable which is later tested in <STRONG>wgetch</STRONG> (see <STRONG><A HREF="curs_getch.3x.html">curs_getch(3x)</A></STRONG>). If
+ <STRONG>keypad</STRONG> has been enabled for the corresponding window, <STRONG>wgetch</STRONG>
+ returns the key symbol <STRONG>KEY_RESIZE</STRONG>. At the same time, <STRONG>wgetch</STRONG> calls
<STRONG>resizeterm</STRONG> to adjust the standard screen <STRONG>stdscr</STRONG>, and update other
data such as <STRONG>LINES</STRONG> and <STRONG>COLS</STRONG>.
</PRE><H2><a name="h2-SEE-ALSO">SEE ALSO</a></H2><PRE>
- <STRONG><A HREF="ncurses.3x.html">curses(3x)</A></STRONG>, <STRONG><A HREF="curs_kernel.3x.html">curs_kernel(3x)</A></STRONG>, <STRONG><A HREF="curs_refresh.3x.html">curs_refresh(3x)</A></STRONG>, <STRONG><A HREF="curs_slk.3x.html">curs_slk(3x)</A></STRONG>, <STRONG>curs_ter-</STRONG>
- <STRONG><A HREF="curs_terminfo.3x.html">minfo(3x)</A></STRONG>, <STRONG><A HREF="curs_util.3x.html">curs_util(3x)</A></STRONG>, <STRONG><A HREF="curs_variables.3x.html">curs_variables(3x)</A></STRONG>.
+ <STRONG><A HREF="ncurses.3x.html">curses(3x)</A></STRONG>, <STRONG><A HREF="curs_kernel.3x.html">curs_kernel(3x)</A></STRONG>, <STRONG><A HREF="curs_refresh.3x.html">curs_refresh(3x)</A></STRONG>, <STRONG><A HREF="curs_slk.3x.html">curs_slk(3x)</A></STRONG>,
+ <STRONG><A HREF="curs_terminfo.3x.html">curs_terminfo(3x)</A></STRONG>, <STRONG><A HREF="curs_util.3x.html">curs_util(3x)</A></STRONG>, <STRONG><A HREF="curs_variables.3x.html">curs_variables(3x)</A></STRONG>.
-ncurses 6.4 2023-08-19 <STRONG><A HREF="curs_initscr.3x.html">curs_initscr(3x)</A></STRONG>
+ncurses 6.4 2023-09-16 <STRONG><A HREF="curs_initscr.3x.html">curs_initscr(3x)</A></STRONG>
</PRE>
<div class="nav">
<ul>