2 ****************************************************************************
3 * Copyright (c) 1998-2014,2015 Free Software Foundation, Inc. *
5 * Permission is hereby granted, free of charge, to any person obtaining a *
6 * copy of this software and associated documentation files (the *
7 * "Software"), to deal in the Software without restriction, including *
8 * without limitation the rights to use, copy, modify, merge, publish, *
9 * distribute, distribute with modifications, sublicense, and/or sell *
10 * copies of the Software, and to permit persons to whom the Software is *
11 * furnished to do so, subject to the following conditions: *
13 * The above copyright notice and this permission notice shall be included *
14 * in all copies or substantial portions of the Software. *
16 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS *
17 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF *
18 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. *
19 * IN NO EVENT SHALL THE ABOVE COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, *
20 * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR *
21 * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR *
22 * THE USE OR OTHER DEALINGS IN THE SOFTWARE. *
24 * Except as contained in this notice, the name(s) of the above copyright *
25 * holders shall not be used in advertising or otherwise to promote the *
26 * sale, use or other dealings in this Software without prior written *
28 ****************************************************************************
29 * @Id: curs_initscr.3x,v 1.24 2015/07/21 23:01:38 tom Exp @
31 <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01//EN">
34 <meta http-equiv="Content-Type" content="text/html; charset=us-ascii">
35 <meta name="generator" content="Manpage converted by man2html - see http://invisible-island.net/scripts/readme.html#others_scripts">
36 <TITLE>curs_initscr 3x</TITLE>
37 <link rev=made href="mailto:bug-ncurses@gnu.org">
38 <meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
41 <H1 class="no-header">curs_initscr 3x</H1>
43 <STRONG><A HREF="curs_initscr.3x.html">curs_initscr(3x)</A></STRONG> <STRONG><A HREF="curs_initscr.3x.html">curs_initscr(3x)</A></STRONG>
48 </PRE><H2><a name="h2-NAME">NAME</a></H2><PRE>
49 <STRONG>initscr</STRONG>, <STRONG>newterm</STRONG>, <STRONG>endwin</STRONG>, <STRONG>isendwin</STRONG>, <STRONG>set_term</STRONG>, <STRONG>delscreen</STRONG> -
50 <STRONG>curses</STRONG> screen initialization and manipulation routines
53 </PRE><H2><a name="h2-SYNOPSIS">SYNOPSIS</a></H2><PRE>
54 <STRONG>#include</STRONG> <STRONG><curses.h></STRONG>
56 <STRONG>WINDOW</STRONG> <STRONG>*initscr(void);</STRONG>
57 <STRONG>int</STRONG> <STRONG>endwin(void);</STRONG>
58 <STRONG>bool</STRONG> <STRONG>isendwin(void);</STRONG>
59 <STRONG>SCREEN</STRONG> <STRONG>*newterm(char</STRONG> <STRONG>*</STRONG><EM>type</EM><STRONG>,</STRONG> <STRONG>FILE</STRONG> <STRONG>*</STRONG><EM>outfd</EM><STRONG>,</STRONG> <STRONG>FILE</STRONG> <STRONG>*</STRONG><EM>infd</EM><STRONG>);</STRONG>
60 <STRONG>SCREEN</STRONG> <STRONG>*set_term(SCREEN</STRONG> <STRONG>*</STRONG><EM>new</EM><STRONG>);</STRONG>
61 <STRONG>void</STRONG> <STRONG>delscreen(SCREEN*</STRONG> <EM>sp</EM><STRONG>);</STRONG>
64 </PRE><H2><a name="h2-DESCRIPTION">DESCRIPTION</a></H2><PRE>
66 </PRE><H3><a name="h3-initscr">initscr</a></H3><PRE>
67 <STRONG>initscr</STRONG> is normally the first <STRONG>curses</STRONG> routine to call when
68 initializing a program. A few special routines sometimes
69 need to be called before it; these are <STRONG>slk_init</STRONG>, <STRONG>filter</STRONG>,
70 <STRONG>ripoffline</STRONG>, <STRONG>use_env</STRONG>. For multiple-terminal applications,
71 <STRONG>newterm</STRONG> may be called before <STRONG>initscr</STRONG>.
73 The initscr code determines the terminal type and initial-
74 izes all <STRONG>curses</STRONG> data structures. <STRONG>initscr</STRONG> also causes the
75 first call to <STRONG>refresh</STRONG> to clear the screen. If errors oc-
76 cur, <STRONG>initscr</STRONG> writes an appropriate error message to stan-
77 dard error and exits; otherwise, a pointer is returned to
78 <STRONG>stdscr</STRONG>.
81 </PRE><H3><a name="h3-newterm">newterm</a></H3><PRE>
82 A program that outputs to more than one terminal should
83 use the <STRONG>newterm</STRONG> routine for each terminal instead of
84 <STRONG>initscr</STRONG>. A program that needs to inspect capabilities, so
85 it can continue to run in a line-oriented mode if the ter-
86 minal cannot support a screen-oriented program, would also
87 use <STRONG>newterm</STRONG>. The routine <STRONG>newterm</STRONG> should be called once
88 for each terminal. It returns a variable of type <STRONG>SCREEN</STRONG> <STRONG>*</STRONG>
89 which should be saved as a reference to that terminal.
90 <STRONG>newterm</STRONG>'s arguments are
92 <STRONG>o</STRONG> the <EM>type</EM> of the terminal to be used in place of <STRONG>$TERM</STRONG>,
94 <STRONG>o</STRONG> a file pointer for output to the terminal, and
96 <STRONG>o</STRONG> another file pointer for input from the terminal
98 If the <EM>type</EM> parameter is <STRONG>NULL</STRONG>, <STRONG>$TERM</STRONG> will be used.
101 </PRE><H3><a name="h3-endwin">endwin</a></H3><PRE>
102 The program must also call <STRONG>endwin</STRONG> for each terminal being
103 used before exiting from <STRONG>curses</STRONG>. If <STRONG>newterm</STRONG> is called
104 more than once for the same terminal, the first terminal
105 referred to must be the last one for which <STRONG>endwin</STRONG> is
108 A program should always call <STRONG>endwin</STRONG> before exiting or es-
109 caping from <STRONG>curses</STRONG> mode temporarily. This routine
111 <STRONG>o</STRONG> restores tty modes,
113 <STRONG>o</STRONG> moves the cursor to the lower left-hand corner of the
116 <STRONG>o</STRONG> resets the terminal into the proper non-visual mode.
118 Calling <STRONG>refresh</STRONG> or <STRONG>doupdate</STRONG> after a temporary escape caus-
119 es the program to resume visual mode.
122 </PRE><H3><a name="h3-isendwin">isendwin</a></H3><PRE>
123 The <STRONG>isendwin</STRONG> routine returns <STRONG>TRUE</STRONG> if <STRONG>endwin</STRONG> has been
124 called without any subsequent calls to <STRONG>wrefresh</STRONG>, and <STRONG>FALSE</STRONG>
128 </PRE><H3><a name="h3-set_term">set_term</a></H3><PRE>
129 The <STRONG>set_term</STRONG> routine is used to switch between different
130 terminals. The screen reference <STRONG>new</STRONG> becomes the new cur-
131 rent terminal. The previous terminal is returned by the
132 routine. This is the only routine which manipulates
133 <STRONG>SCREEN</STRONG> pointers; all other routines affect only the cur-
137 </PRE><H3><a name="h3-delscreen">delscreen</a></H3><PRE>
138 The <STRONG>delscreen</STRONG> routine frees storage associated with the
139 <STRONG>SCREEN</STRONG> data structure. The <STRONG>endwin</STRONG> routine does not do
140 this, so <STRONG>delscreen</STRONG> should be called after <STRONG>endwin</STRONG> if a par-
141 ticular <STRONG>SCREEN</STRONG> is no longer needed.
144 </PRE><H2><a name="h2-RETURN-VALUE">RETURN VALUE</a></H2><PRE>
145 <STRONG>endwin</STRONG> returns the integer <STRONG>ERR</STRONG> upon failure and <STRONG>OK</STRONG> upon
146 successful completion.
148 Routines that return pointers always return <STRONG>NULL</STRONG> on error.
150 X/Open defines no error conditions. In this implementa-
153 <STRONG>o</STRONG> <STRONG>endwin</STRONG> returns an error if the terminal was not ini-
156 <STRONG>o</STRONG> <STRONG>newterm</STRONG> returns an error if it cannot allocate the da-
157 ta structures for the screen, or for the top-level
158 windows within the screen, i.e., <STRONG>curscr</STRONG>, <STRONG>newscr</STRONG>, or
159 <STRONG>stdscr</STRONG>.
161 <STRONG>o</STRONG> <STRONG>set_term</STRONG> returns no error.
164 </PRE><H2><a name="h2-NOTES">NOTES</a></H2><PRE>
165 Note that <STRONG>initscr</STRONG> and <STRONG>newterm</STRONG> may be macros.
168 </PRE><H2><a name="h2-PORTABILITY">PORTABILITY</a></H2><PRE>
169 These functions were described in the XSI Curses standard,
170 Issue 4. As of 2015, the current document is X/Open Curs-
174 </PRE><H3><a name="h3-Differences">Differences</a></H3><PRE>
175 X/Open specifies that portable applications must not call
176 <STRONG>initscr</STRONG> more than once:
178 <STRONG>o</STRONG> The portable way to use <STRONG>initscr</STRONG> is once only, using
179 <STRONG>refresh</STRONG> (see <STRONG><A HREF="curs_refresh.3x.html">curs_refresh(3x)</A></STRONG>) to restore the screen
180 after <STRONG>endwin</STRONG>.
182 <STRONG>o</STRONG> This implementation allows using <STRONG>initscr</STRONG> after <STRONG>endwin</STRONG>.
184 Old versions of curses, e.g., BSD 4.4, may have returned a
185 null pointer from <STRONG>initscr</STRONG> when an error is detected,
186 rather than exiting. It is safe but redundant to check
187 the return value of <STRONG>initscr</STRONG> in XSI Curses.
190 </PRE><H3><a name="h3-Unset-TERM-Variable">Unset TERM Variable</a></H3><PRE>
191 If the TERM variable is missing or empty, <STRONG>initscr</STRONG> uses the
192 value "unknown", which normally corresponds to a terminal
193 entry with the <EM>generic</EM> (<EM>gn</EM>) capability. Generic entries
194 are detected by <STRONG>setupterm</STRONG> (see <STRONG><A HREF="curs_terminfo.3x.html">curs_terminfo(3x)</A></STRONG>) and can-
195 not be used for full-screen operation. Other implementa-
196 tions may handle a missing/empty TERM variable different-
200 </PRE><H3><a name="h3-Signal-Handlers">Signal Handlers</a></H3><PRE>
201 Quoting from X/Open Curses, section 3.1.1:
203 <EM>Curses</EM> <EM>implementations</EM> <EM>may</EM> <EM>provide</EM> <EM>for</EM> <EM>special</EM> <EM>han-</EM>
204 <EM>dling</EM> <EM>of</EM> <EM>the</EM> <EM>SIGINT,</EM> <EM>SIGQUIT</EM> <EM>and</EM> <EM>SIGTSTP</EM> <EM>signals</EM> <EM>if</EM>
205 <EM>their</EM> <EM>disposition</EM> <EM>is</EM> <EM>SIG</EM><STRONG>_</STRONG><EM>DFL</EM> <EM>at</EM> <EM>the</EM> <EM>time</EM> <STRONG>initscr()</STRONG> <EM>is</EM>
206 <EM>called</EM> <STRONG>...</STRONG>
208 <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>
209 <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>
210 <EM>process</EM> <EM>changes</EM> <EM>the</EM> <EM>disposition</EM> <EM>of</EM> <EM>the</EM> <EM>signal.</EM>
212 <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>
213 <EM>with</EM> <EM>respect</EM> <EM>to</EM> <EM>signals</EM> ...
215 This implementation establishes signal handlers during
216 initialization, e.g., <STRONG>initscr</STRONG> or <STRONG>newterm</STRONG>. Applications
217 which must handle these signals should set up the corre-
218 sponding handlers <EM>after</EM> initializing the library:
220 <STRONG>SIGINT</STRONG>
221 The handler <EM>attempts</EM> to cleanup the screen on exit.
222 Although it <EM>usually</EM> works as expected, there are lim-
225 <STRONG>o</STRONG> Walking the <STRONG>SCREEN</STRONG> list is unsafe, since all list
226 management is done without any signal blocking.
228 <STRONG>o</STRONG> On systems which have <STRONG>REENTRANT</STRONG> turned on,
229 <STRONG>set_term</STRONG> uses functions which could deadlock or
230 misbehave in other ways.
232 <STRONG>o</STRONG> <STRONG>endwin</STRONG> calls other functions, many of which use
233 stdio or other library functions which are clear-
236 <STRONG>SIGTERM</STRONG>
237 This uses the same handler as <STRONG>SIGINT</STRONG>, with the same
238 limitations. It is not mentioned in X/Open Curses,
239 but is more suitable for this purpose than <STRONG>SIGQUIT</STRONG>
240 (which is used in debugging).
242 <STRONG>SIGTSTP</STRONG>
243 This handles the <EM>stop</EM> signal, used in job control.
244 When resuming the process, this implementation dis-
245 cards pending input with <STRONG>flushinput</STRONG> (see
246 <STRONG><A HREF="curs_util.3x.html">curs_util(3x)</A></STRONG>), and repaints the screen assuming that
247 it has been completely altered. It also updates the
248 saved terminal modes with <STRONG>def_shell_mode</STRONG> (see
249 <STRONG><A HREF="curs_kernel.3x.html">curs_kernel(3x)</A></STRONG>).
251 <STRONG>SIGWINCH</STRONG>
252 This handles the window-size changes which were ini-
253 tially ignored in the standardization efforts. The
254 handler sets a (signal-safe) variable which is later
255 tested in <STRONG>wgetch</STRONG> (see <STRONG><A HREF="curs_getch.3x.html">curs_getch(3x)</A></STRONG>). If <STRONG>keypad</STRONG> has
256 been enabled for the corresponding window, <STRONG>wgetch</STRONG> re-
257 turns the key symbol <STRONG>KEY_RESIZE</STRONG>. At the same time,
258 <STRONG>wgetch</STRONG> calls <STRONG>resizeterm</STRONG> to adjust the standard screen
259 <STRONG>stdscr</STRONG>, and update other data such as <STRONG>LINES</STRONG> and <STRONG>COLS</STRONG>.
262 </PRE><H2><a name="h2-SEE-ALSO">SEE ALSO</a></H2><PRE>
263 <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>,
264 <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>curs_vari-</STRONG>
265 <STRONG><A HREF="curs_variables.3x.html">ables(3x)</A></STRONG>.
269 <STRONG><A HREF="curs_initscr.3x.html">curs_initscr(3x)</A></STRONG>
273 <li><a href="#h2-NAME">NAME</a></li>
274 <li><a href="#h2-SYNOPSIS">SYNOPSIS</a></li>
275 <li><a href="#h2-DESCRIPTION">DESCRIPTION</a>
277 <li><a href="#h3-initscr">initscr</a></li>
278 <li><a href="#h3-newterm">newterm</a></li>
279 <li><a href="#h3-endwin">endwin</a></li>
280 <li><a href="#h3-isendwin">isendwin</a></li>
281 <li><a href="#h3-set_term">set_term</a></li>
282 <li><a href="#h3-delscreen">delscreen</a></li>
285 <li><a href="#h2-RETURN-VALUE">RETURN VALUE</a></li>
286 <li><a href="#h2-NOTES">NOTES</a></li>
287 <li><a href="#h2-PORTABILITY">PORTABILITY</a>
289 <li><a href="#h3-Differences">Differences</a></li>
290 <li><a href="#h3-Unset-TERM-Variable">Unset TERM Variable</a></li>
291 <li><a href="#h3-Signal-Handlers">Signal Handlers</a></li>
294 <li><a href="#h2-SEE-ALSO">SEE ALSO</a></li>