doc/html/man/curs_initscr.3x.html

   1 <!--
   2   ****************************************************************************
   3   * Copyright (c) 1998-2014,2015 Free Software Foundation, Inc.              *
   4   *                                                                          *
   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:                 *
  12   *                                                                          *
  13   * The above copyright notice and this permission notice shall be included  *
  14   * in all copies or substantial portions of the Software.                   *
  15   *                                                                          *
  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.                               *
  23   *                                                                          *
  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       *
  27   * authorization.                                                           *
  28   ****************************************************************************
  29   * @Id: curs_initscr.3x,v 1.23 2015/07/16 09:23:42 tom Exp @
  30 -->
  31 <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01//EN">
  32 <HTML>
  33 <HEAD>
  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">
  39 </HEAD>
  40 <BODY>
  41 <H1 class="no-header">curs_initscr 3x</H1>
  42 <PRE>
  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>
  44
  45
  46
  47
  48 </PRE>
  49 <H2><a name="h2-NAME">NAME</a></H2><PRE>
  50        <STRONG>initscr</STRONG>, <STRONG>newterm</STRONG>, <STRONG>endwin</STRONG>, <STRONG>isendwin</STRONG>, <STRONG>set_term</STRONG>, <STRONG>delscreen</STRONG> -
  51        <STRONG>curses</STRONG> screen initialization and manipulation routines
  52
  53
  54 </PRE>
  55 <H2><a name="h2-SYNOPSIS">SYNOPSIS</a></H2><PRE>
  56        <STRONG>#include</STRONG> <STRONG>&lt;curses.h&gt;</STRONG>
  57
  58        <STRONG>WINDOW</STRONG> <STRONG>*initscr(void);</STRONG>
  59        <STRONG>int</STRONG> <STRONG>endwin(void);</STRONG>
  60        <STRONG>bool</STRONG> <STRONG>isendwin(void);</STRONG>
  61        <STRONG>SCREEN</STRONG> <STRONG>*newterm(char</STRONG> <STRONG>*type,</STRONG> <STRONG>FILE</STRONG> <STRONG>*outfd,</STRONG> <STRONG>FILE</STRONG> <STRONG>*infd);</STRONG>
  62        <STRONG>SCREEN</STRONG> <STRONG>*set_term(SCREEN</STRONG> <STRONG>*new);</STRONG>
  63        <STRONG>void</STRONG> <STRONG>delscreen(SCREEN*</STRONG> <STRONG>sp);</STRONG>
  64
  65
  66 </PRE>
  67 <H2><a name="h2-DESCRIPTION">DESCRIPTION</a></H2><PRE>
  68
  69 </PRE>
  70 <H3><a name="h3-initscr">initscr</a></H3><PRE>
  71        <STRONG>initscr</STRONG> is normally the first <STRONG>curses</STRONG> routine to call  when
  72        initializing  a program.  A few special routines sometimes
  73        need to be called before it; these are  <STRONG>slk_init</STRONG>,  <STRONG>filter</STRONG>,
  74        <STRONG>ripoffline</STRONG>,  <STRONG>use_env</STRONG>.  For multiple-terminal applications,
  75        <STRONG>newterm</STRONG> may be called before <STRONG>initscr</STRONG>.
  76
  77        The initscr code determines the terminal type and initial-
  78        izes  all <STRONG>curses</STRONG> data structures.  <STRONG>initscr</STRONG> also causes the
  79        first call to <STRONG>refresh</STRONG> to clear the screen.  If errors  oc-
  80        cur,  <STRONG>initscr</STRONG> writes an appropriate error message to stan-
  81        dard error and exits; otherwise, a pointer is returned  to
  82        <STRONG>stdscr</STRONG>.
  83
  84
  85 </PRE>
  86 <H3><a name="h3-newterm">newterm</a></H3><PRE>
  87        A  program  that  outputs to more than one terminal should
  88        use the <STRONG>newterm</STRONG>  routine  for  each  terminal  instead  of
  89        <STRONG>initscr</STRONG>.  A program that needs to inspect capabilities, so
  90        it can continue to run in a line-oriented mode if the ter-
  91        minal cannot support a screen-oriented program, would also
  92        use <STRONG>newterm</STRONG>.  The routine <STRONG>newterm</STRONG> should  be  called  once
  93        for each terminal.  It returns a variable of type <STRONG>SCREEN</STRONG> <STRONG>*</STRONG>
  94        which should be saved as a  reference  to  that  terminal.
  95        <STRONG>newterm</STRONG>'s arguments are
  96
  97        <STRONG>o</STRONG>   the <EM>type</EM> of the terminal to be used in place of <STRONG>$TERM</STRONG>,
  98
  99        <STRONG>o</STRONG>   a file pointer for output to the terminal, and
 100
 101        <STRONG>o</STRONG>   another file pointer for input from the terminal
 102
 103        If the <EM>type</EM> parameter is <STRONG>NULL</STRONG>, <STRONG>$TERM</STRONG> will be used.
 104
 105
 106 </PRE>
 107 <H3><a name="h3-endwin">endwin</a></H3><PRE>
 108        The  program must also call <STRONG>endwin</STRONG> for each terminal being
 109        used before exiting from <STRONG>curses</STRONG>.   If  <STRONG>newterm</STRONG>  is  called
 110        more  than  once for the same terminal, the first terminal
 111        referred to must be the  last  one  for  which  <STRONG>endwin</STRONG>  is
 112        called.
 113
 114        A  program should always call <STRONG>endwin</STRONG> before exiting or es-
 115        caping from <STRONG>curses</STRONG> mode temporarily.  This routine
 116
 117        <STRONG>o</STRONG>   restores tty modes,
 118
 119        <STRONG>o</STRONG>   moves the cursor to the lower left-hand corner of  the
 120            screen and
 121
 122        <STRONG>o</STRONG>   resets the terminal into the proper non-visual mode.
 123
 124        Calling <STRONG>refresh</STRONG> or <STRONG>doupdate</STRONG> after a temporary escape caus-
 125        es the program to resume visual mode.
 126
 127
 128 </PRE>
 129 <H3><a name="h3-isendwin">isendwin</a></H3><PRE>
 130        The <STRONG>isendwin</STRONG> routine  returns  <STRONG>TRUE</STRONG>  if  <STRONG>endwin</STRONG>  has  been
 131        called without any subsequent calls to <STRONG>wrefresh</STRONG>, and <STRONG>FALSE</STRONG>
 132        otherwise.
 133
 134
 135 </PRE>
 136 <H3><a name="h3-set_term">set_term</a></H3><PRE>
 137        The <STRONG>set_term</STRONG> routine is used to switch  between  different
 138        terminals.   The screen reference <STRONG>new</STRONG> becomes the new cur-
 139        rent terminal.  The previous terminal is returned  by  the
 140        routine.   This  is  the  only  routine  which manipulates
 141        <STRONG>SCREEN</STRONG> pointers; all other routines affect only  the  cur-
 142        rent terminal.
 143
 144
 145 </PRE>
 146 <H3><a name="h3-delscreen">delscreen</a></H3><PRE>
 147        The  <STRONG>delscreen</STRONG>  routine  frees storage associated with the
 148        <STRONG>SCREEN</STRONG> data structure.  The <STRONG>endwin</STRONG>  routine  does  not  do
 149        this, so <STRONG>delscreen</STRONG> should be called after <STRONG>endwin</STRONG> if a par-
 150        ticular <STRONG>SCREEN</STRONG> is no longer needed.
 151
 152
 153 </PRE>
 154 <H2><a name="h2-RETURN-VALUE">RETURN VALUE</a></H2><PRE>
 155        <STRONG>endwin</STRONG> returns the integer <STRONG>ERR</STRONG> upon failure  and  <STRONG>OK</STRONG>  upon
 156        successful completion.
 157
 158        Routines that return pointers always return <STRONG>NULL</STRONG> on error.
 159
 160        X/Open  defines  no error conditions.  In this implementa-
 161        tion
 162
 163        <STRONG>o</STRONG>   <STRONG>endwin</STRONG> returns an error if the terminal was  not  ini-
 164            tialized.
 165
 166        <STRONG>o</STRONG>   <STRONG>newterm</STRONG> returns an error if it cannot allocate the da-
 167            ta structures for the screen,  or  for  the  top-level
 168            windows  within  the  screen, i.e., <STRONG>curscr</STRONG>, <STRONG>newscr</STRONG>, or
 169            <STRONG>stdscr</STRONG>.
 170
 171        <STRONG>o</STRONG>   <STRONG>set_term</STRONG> returns no error.
 172
 173
 174 </PRE>
 175 <H2><a name="h2-NOTES">NOTES</a></H2><PRE>
 176        Note that <STRONG>initscr</STRONG> and <STRONG>newterm</STRONG> may be macros.
 177
 178
 179 </PRE>
 180 <H2><a name="h2-PORTABILITY">PORTABILITY</a></H2><PRE>
 181        These functions were described in the XSI Curses standard,
 182        Issue 4.  As of 2015, the current document is X/Open Curs-
 183        es, Issue 7.
 184
 185
 186 </PRE>
 187 <H3><a name="h3-Differences">Differences</a></H3><PRE>
 188        X/Open specifies that portable applications must not  call
 189        <STRONG>initscr</STRONG> more than once:
 190
 191        <STRONG>o</STRONG>   The  portable  way  to use <STRONG>initscr</STRONG> is once only, using
 192            <STRONG>refresh</STRONG> (see <STRONG><A HREF="curs_refresh.3x.html">curs_refresh(3x)</A></STRONG>) to restore  the  screen
 193            after <STRONG>endwin</STRONG>.
 194
 195        <STRONG>o</STRONG>   This implementation allows using <STRONG>initscr</STRONG> after <STRONG>endwin</STRONG>.
 196
 197        Old versions of curses, e.g., BSD 4.4, may have returned a
 198        null pointer from  <STRONG>initscr</STRONG>  when  an  error  is  detected,
 199        rather  than  exiting.   It is safe but redundant to check
 200        the return value of <STRONG>initscr</STRONG> in XSI Curses.
 201
 202
 203 </PRE>
 204 <H3><a name="h3-Unset-TERM-Variable">Unset TERM Variable</a></H3><PRE>
 205        If the TERM variable is missing or empty, <STRONG>initscr</STRONG> uses the
 206        value  "unknown", which normally corresponds to a terminal
 207        entry with the <EM>generic</EM> (<EM>gn</EM>) capability.   Generic  entries
 208        are detected by <STRONG>setupterm</STRONG> (see <STRONG><A HREF="curs_terminfo.3x.html">curs_terminfo(3x)</A></STRONG>) and can-
 209        not be used for full-screen operation.  Other  implementa-
 210        tions  may handle a missing/empty TERM variable different-
 211        ly.
 212
 213
 214 </PRE>
 215 <H3><a name="h3-Signal-Handlers">Signal Handlers</a></H3><PRE>
 216        Quoting from X/Open Curses, section 3.1.1:
 217
 218             <EM>Curses</EM> <EM>implementations</EM> <EM>may</EM> <EM>provide</EM> <EM>for</EM>  <EM>special</EM>  <EM>han-</EM>
 219             <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>
 220             <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>
 221             <EM>called</EM> <STRONG>...</STRONG>
 222
 223             <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>
 224             <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>
 225             <EM>process</EM> <EM>changes</EM> <EM>the</EM> <EM>disposition</EM> <EM>of</EM> <EM>the</EM> <EM>signal.</EM>
 226
 227             <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>
 228             <EM>with</EM> <EM>respect</EM> <EM>to</EM> <EM>signals</EM> ...
 229
 230        This implementation  establishes  signal  handlers  during
 231        initialization,  e.g.,  <STRONG>initscr</STRONG>  or <STRONG>newterm</STRONG>.  Applications
 232        which must handle these signals should set up  the  corre-
 233        sponding handlers <EM>after</EM> initializing the library:
 234
 235        <STRONG>SIGINT</STRONG>
 236             The  handler  <EM>attempts</EM> to cleanup the screen on exit.
 237             Although it <EM>usually</EM> works as expected, there are lim-
 238             itations:
 239
 240             <STRONG>o</STRONG>   Walking the <STRONG>SCREEN</STRONG> list is unsafe, since all list
 241                 management is done without any signal blocking.
 242
 243             <STRONG>o</STRONG>   On  systems  which  have  <STRONG>REENTRANT</STRONG>  turned   on,
 244                 <STRONG>set_term</STRONG>  uses  functions which could deadlock or
 245                 misbehave in other ways.
 246
 247             <STRONG>o</STRONG>   <STRONG>endwin</STRONG> calls other functions, many of  which  use
 248                 stdio or other library functions which are clear-
 249                 ly unsafe.
 250
 251        <STRONG>SIGTERM</STRONG>
 252             This uses the same handler as <STRONG>SIGINT</STRONG>, with  the  same
 253             limitations.   It  is not mentioned in X/Open Curses,
 254             but is more suitable for this  purpose  than  <STRONG>SIGQUIT</STRONG>
 255             (which is used in debugging).
 256
 257        <STRONG>SIGTSTP</STRONG>
 258             This  handles  the  <EM>stop</EM> signal, used in job control.
 259             When resuming the process, this  implementation  dis-
 260             cards    pending    input    with   <STRONG>flushinput</STRONG>   (see
 261             <STRONG><A HREF="curs_util.3x.html">curs_util(3x)</A></STRONG>), and repaints the screen assuming that
 262             it  has been completely altered.  It also updates the
 263             saved  terminal  modes   with   <STRONG>def_shell_mode</STRONG>   (see
 264             <STRONG><A HREF="curs_kernel.3x.html">curs_kernel(3x)</A></STRONG>).
 265
 266        <STRONG>SIGWINCH</STRONG>
 267             This  handles the window-size changes which were ini-
 268             tially ignored in the standardization  efforts.   The
 269             handler  sets a (signal-safe) variable which is later
 270             tested in <STRONG>wgetch</STRONG> (see <STRONG><A HREF="curs_getch.3x.html">curs_getch(3x)</A></STRONG>).  If <STRONG>keypad</STRONG> has
 271             been enabled for the corresponding window, <STRONG>wgetch</STRONG> re-
 272             turns the key symbol <STRONG>KEY_RESIZE</STRONG>.  At the  same  time,
 273             <STRONG>wgetch</STRONG> calls <STRONG>resizeterm</STRONG> to adjust the standard screen
 274             <STRONG>stdscr</STRONG>, and update other data such as <STRONG>LINES</STRONG> and <STRONG>COLS</STRONG>.
 275
 276
 277 </PRE>
 278 <H2><a name="h2-SEE-ALSO">SEE ALSO</a></H2><PRE>
 279        <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>,
 280        <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>
 281        <STRONG><A HREF="curs_variables.3x.html">ables(3x)</A></STRONG>.
 282
 283
 284
 285                                                        <STRONG><A HREF="curs_initscr.3x.html">curs_initscr(3x)</A></STRONG>
 286 </PRE>
 287 <div class="nav">
 288 <ul>
 289 <li><a href="#h2-NAME">NAME</a></li>
 290 <li><a href="#h2-SYNOPSIS">SYNOPSIS</a></li>
 291 <li><a href="#h2-DESCRIPTION">DESCRIPTION</a>
 292 <ul>
 293 <li><a href="#h3-initscr">initscr</a></li>
 294 <li><a href="#h3-newterm">newterm</a></li>
 295 <li><a href="#h3-endwin">endwin</a></li>
 296 <li><a href="#h3-isendwin">isendwin</a></li>
 297 <li><a href="#h3-set_term">set_term</a></li>
 298 <li><a href="#h3-delscreen">delscreen</a></li>
 299 </ul>
 300 </li>
 301 <li><a href="#h2-RETURN-VALUE">RETURN VALUE</a></li>
 302 <li><a href="#h2-NOTES">NOTES</a></li>
 303 <li><a href="#h2-PORTABILITY">PORTABILITY</a>
 304 <ul>
 305 <li><a href="#h3-Differences">Differences</a></li>
 306 <li><a href="#h3-Unset-TERM-Variable">Unset TERM Variable</a></li>
 307 <li><a href="#h3-Signal-Handlers">Signal Handlers</a></li>
 308 </ul>
 309 </li>
 310 <li><a href="#h2-SEE-ALSO">SEE ALSO</a></li>
 311 </ul>
 312 </div>
 313 </BODY>
 314 </HTML>