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| <H1 class="no-header">curs_initscr 3x</H1> |
| <PRE> |
| <STRONG><A HREF="curs_initscr.3x.html">curs_initscr(3x)</A></STRONG> <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 |
| |
| |
| </PRE> |
| <H2><a name="h2-SYNOPSIS">SYNOPSIS</a></H2><PRE> |
| <STRONG>#include</STRONG> <STRONG><curses.h></STRONG> |
| |
| <STRONG>WINDOW</STRONG> <STRONG>*initscr(void);</STRONG> |
| <STRONG>int</STRONG> <STRONG>endwin(void);</STRONG> |
| <STRONG>bool</STRONG> <STRONG>isendwin(void);</STRONG> |
| <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> |
| <STRONG>SCREEN</STRONG> <STRONG>*set_term(SCREEN</STRONG> <STRONG>*</STRONG><EM>new</EM><STRONG>);</STRONG> |
| <STRONG>void</STRONG> <STRONG>delscreen(SCREEN*</STRONG> <EM>sp</EM><STRONG>);</STRONG> |
| |
| |
| </PRE> |
| <H2><a name="h2-DESCRIPTION">DESCRIPTION</a></H2><PRE> |
| |
| </PRE> |
| <H3><a name="h3-initscr">initscr</a></H3><PRE> |
| <STRONG>initscr</STRONG> is normally the first <STRONG>curses</STRONG> routine to call when |
| initializing a program. A few special routines sometimes |
| need to be called before it; these are <STRONG>slk_init</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 initial- |
| izes all <STRONG>curses</STRONG> data structures. <STRONG>initscr</STRONG> also causes the |
| first call to <STRONG>refresh</STRONG> to clear the screen. If errors oc- |
| cur, <STRONG>initscr</STRONG> writes an appropriate error message to stan- |
| dard error and exits; otherwise, a pointer is returned to |
| <STRONG>stdscr</STRONG>. |
| |
| |
| </PRE> |
| <H3><a name="h3-newterm">newterm</a></H3><PRE> |
| A program that outputs to more than one terminal should |
| use the <STRONG>newterm</STRONG> routine for each terminal instead of |
| <STRONG>initscr</STRONG>. A program that needs to inspect capabilities, so |
| it can continue to run in a line-oriented mode if the ter- |
| minal 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 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>$TERM</STRONG>, |
| |
| <STRONG>o</STRONG> a file pointer for output to the terminal, and |
| |
| <STRONG>o</STRONG> another file pointer for input from the terminal |
| |
| If the <EM>type</EM> parameter is <STRONG>NULL</STRONG>, <STRONG>$TERM</STRONG> will be used. |
| |
| |
| </PRE> |
| <H3><a name="h3-endwin">endwin</a></H3><PRE> |
| The program must also call <STRONG>endwin</STRONG> for each terminal being |
| used before exiting from <STRONG>curses</STRONG>. If <STRONG>newterm</STRONG> is called |
| more than once for the same terminal, the first terminal |
| referred to must be the last one for which <STRONG>endwin</STRONG> is |
| called. |
| |
| A program should always call <STRONG>endwin</STRONG> before exiting or es- |
| caping from <STRONG>curses</STRONG> mode temporarily. This routine |
| |
| <STRONG>o</STRONG> restores tty modes, |
| |
| <STRONG>o</STRONG> moves the cursor to the lower left-hand corner of the |
| screen and |
| |
| <STRONG>o</STRONG> resets the terminal into the proper non-visual mode. |
| |
| Calling <STRONG>refresh</STRONG> or <STRONG>doupdate</STRONG> after a temporary escape caus- |
| es the program to resume visual mode. |
| |
| |
| </PRE> |
| <H3><a name="h3-isendwin">isendwin</a></H3><PRE> |
| The <STRONG>isendwin</STRONG> routine returns <STRONG>TRUE</STRONG> if <STRONG>endwin</STRONG> has been |
| called without any subsequent calls to <STRONG>wrefresh</STRONG>, and <STRONG>FALSE</STRONG> |
| otherwise. |
| |
| |
| </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 <STRONG>new</STRONG> becomes the new cur- |
| rent 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 cur- |
| rent terminal. |
| |
| |
| </PRE> |
| <H3><a name="h3-delscreen">delscreen</a></H3><PRE> |
| The <STRONG>delscreen</STRONG> routine frees storage associated with the |
| <STRONG>SCREEN</STRONG> data structure. The <STRONG>endwin</STRONG> routine does not do |
| this, so <STRONG>delscreen</STRONG> should be called after <STRONG>endwin</STRONG> if a par- |
| ticular <STRONG>SCREEN</STRONG> is no longer needed. |
| |
| |
| </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 completion. |
| |
| Routines that return pointers always return <STRONG>NULL</STRONG> on error. |
| |
| X/Open defines no error conditions. In this implementa- |
| tion |
| |
| <STRONG>o</STRONG> <STRONG>endwin</STRONG> returns an error if the terminal was not ini- |
| tialized. |
| |
| <STRONG>o</STRONG> <STRONG>newterm</STRONG> returns an error if it cannot allocate the da- |
| ta structures for the screen, or for the top-level |
| windows within the screen, i.e., <STRONG>curscr</STRONG>, <STRONG>newscr</STRONG>, or |
| <STRONG>stdscr</STRONG>. |
| |
| <STRONG>o</STRONG> <STRONG>set_term</STRONG> returns no error. |
| |
| |
| </PRE> |
| <H2><a name="h2-NOTES">NOTES</a></H2><PRE> |
| Note that <STRONG>initscr</STRONG> and <STRONG>newterm</STRONG> may be macros. |
| |
| |
| </PRE> |
| <H2><a name="h2-PORTABILITY">PORTABILITY</a></H2><PRE> |
| These functions were described in the XSI Curses standard, |
| Issue 4. As of 2015, the current document is X/Open Curs- |
| es, Issue 7. |
| |
| |
| </PRE> |
| <H3><a name="h3-Differences">Differences</a></H3><PRE> |
| X/Open specifies that portable applications must not call |
| <STRONG>initscr</STRONG> more than once: |
| |
| <STRONG>o</STRONG> The portable way to use <STRONG>initscr</STRONG> is once only, using |
| <STRONG>refresh</STRONG> (see <STRONG><A HREF="curs_refresh.3x.html">curs_refresh(3x)</A></STRONG>) to restore the screen |
| after <STRONG>endwin</STRONG>. |
| |
| <STRONG>o</STRONG> This implementation allows using <STRONG>initscr</STRONG> after <STRONG>endwin</STRONG>. |
| |
| Old versions of curses, e.g., BSD 4.4, may have returned a |
| null pointer from <STRONG>initscr</STRONG> when an error is detected, |
| rather than exiting. It is safe but redundant to check |
| the return value of <STRONG>initscr</STRONG> in XSI Curses. |
| |
| |
| </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 "unknown", which normally corresponds to a terminal |
| entry with the <EM>generic</EM> (<EM>gn</EM>) capability. Generic entries |
| are detected by <STRONG>setupterm</STRONG> (see <STRONG><A HREF="curs_terminfo.3x.html">curs_terminfo(3x)</A></STRONG>) and can- |
| not be used for full-screen operation. Other implementa- |
| tions may handle a missing/empty TERM variable different- |
| ly. |
| |
| |
| </PRE> |
| <H3><a name="h3-Signal-Handlers">Signal Handlers</a></H3><PRE> |
| Quoting from X/Open Curses, section 3.1.1: |
| |
| <EM>Curses</EM> <EM>implementations</EM> <EM>may</EM> <EM>provide</EM> <EM>for</EM> <EM>special</EM> <EM>han-</EM> |
| <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> |
| <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> |
| <EM>called</EM> <STRONG>...</STRONG> |
| |
| <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> |
| |
| <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> ... |
| |
| 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 corre- |
| sponding handlers <EM>after</EM> initializing the library: |
| |
| <STRONG>SIGINT</STRONG> |
| The handler <EM>attempts</EM> to cleanup the screen on exit. |
| Although it <EM>usually</EM> works as expected, there are lim- |
| itations: |
| |
| <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 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 clear- |
| ly unsafe. |
| |
| <STRONG>SIGTERM</STRONG> |
| This uses the same handler as <STRONG>SIGINT</STRONG>, with the same |
| limitations. It is not mentioned in X/Open Curses, |
| but is more suitable for this purpose than <STRONG>SIGQUIT</STRONG> |
| (which is used in debugging). |
| |
| <STRONG>SIGTSTP</STRONG> |
| This handles the <EM>stop</EM> signal, used in job control. |
| When resuming the process, this implementation dis- |
| cards pending input with <STRONG>flushinput</STRONG> (see |
| <STRONG><A HREF="curs_util.3x.html">curs_util(3x)</A></STRONG>), and repaints the screen assuming that |
| it has been completely altered. It also updates the |
| saved terminal modes with <STRONG>def_shell_mode</STRONG> (see |
| <STRONG><A HREF="curs_kernel.3x.html">curs_kernel(3x)</A></STRONG>). |
| |
| <STRONG>SIGWINCH</STRONG> |
| This handles the window-size changes which were ini- |
| tially ignored in the 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> re- |
| turns 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><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> |
| <STRONG><A HREF="curs_variables.3x.html">ables(3x)</A></STRONG>. |
| |
| |
| |
| <STRONG><A HREF="curs_initscr.3x.html">curs_initscr(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> |
| <ul> |
| <li><a href="#h3-initscr">initscr</a></li> |
| <li><a href="#h3-newterm">newterm</a></li> |
| <li><a href="#h3-endwin">endwin</a></li> |
| <li><a href="#h3-isendwin">isendwin</a></li> |
| <li><a href="#h3-set_term">set_term</a></li> |
| <li><a href="#h3-delscreen">delscreen</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> |
| <ul> |
| <li><a href="#h3-Differences">Differences</a></li> |
| <li><a href="#h3-Unset-TERM-Variable">Unset TERM Variable</a></li> |
| <li><a href="#h3-Signal-Handlers">Signal Handlers</a></li> |
| </ul> |
| </li> |
| <li><a href="#h2-SEE-ALSO">SEE ALSO</a></li> |
| </ul> |
| </div> |
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