- <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>.
+ <I>Curses</I> <I>implementations</I> <I>may</I> <I>provide</I> <I>for</I> <I>special</I> <I>handling</I> <I>of</I> <I>the</I>
+ <B>SIGINT</B><I>,</I> <B>SIGQUIT</B> <I>and</I> <B>SIGTSTP</B> <I>signals</I> <I>if</I> <I>their</I> <I>disposition</I> <I>is</I>
+ <B>SIG_DFL</B> <I>at</I> <I>the</I> <I>time</I> <B>initscr</B> <I>is</I> <I>called</I> <B>...</B>
+
+ <I>Any</I> <I>special</I> <I>handling</I> <I>for</I> <I>these</I> <I>signals</I> <I>may</I> <I>remain</I> <I>in</I> <I>effect</I> <I>for</I>
+ <I>the</I> <I>life</I> <I>of</I> <I>the</I> <I>process</I> <I>or</I> <I>until</I> <I>the</I> <I>process</I> <I>changes</I> <I>the</I> <I>disposi-</I>
+ <I>tion</I> <I>of</I> <I>the</I> <I>signal.</I>
+
+ <I>None</I> <I>of</I> <I>the</I> <I>Curses</I> <I>functions</I> <I>are</I> <I>required</I> <I>to</I> <I>be</I> <I>safe</I> <I>with</I> <I>respect</I>
+ <I>to</I> <I>signals</I> ...
+
+ This implementation establishes signal handlers during initialization,
+ e.g., <B>initscr</B> or <B>newterm</B>. Applications which must handle these signals
+ should set up the corresponding handlers <I>after</I> initializing the li-
+ brary:
+
+ <B>SIGINT</B>
+ The handler <I>attempts</I> to cleanup the screen on exit. Although it
+ <I>usually</I> works as expected, there are limitations:
+
+ <B>o</B> Walking the <B>SCREEN</B> list is unsafe, since all list management
+ is done without any signal blocking.
+
+ <B>o</B> On systems which have <B>REENTRANT</B> turned on, <B>set_term</B> uses func-
+ tions which could deadlock or misbehave in other ways.
+
+ <B>o</B> <B>endwin</B> calls other functions, many of which use stdio or other
+ library functions which are clearly unsafe.
+
+ <B>SIGTERM</B>
+ This uses the same handler as <B>SIGINT</B>, with the same limitations.
+ It is not mentioned in X/Open Curses, but is more suitable for
+ this purpose than <B>SIGQUIT</B> (which is used in debugging).
+
+ <B>SIGTSTP</B>
+ This handles the <I>stop</I> signal, used in job control. When resuming
+ the process, this implementation discards pending input with
+ <B>flushinput</B> (see <B><A HREF="curs_util.3X.html">curs_util(3X)</A></B>), and repaints the screen assuming
+ that it has been completely altered. It also updates the saved
+ terminal modes with <B>def_shell_mode</B> (see <B><A HREF="curs_kernel.3X.html">curs_kernel(3X)</A></B>).
+
+ <B>SIGWINCH</B>
+ 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 <B>wgetch</B> (see <B><A HREF="curs_getch.3X.html">curs_getch(3X)</A></B>). If
+ <B>keypad</B> has been enabled for the corresponding window, <B>wgetch</B> re-
+ turns the key symbol <B>KEY_RESIZE</B>. At the same time, <B>wgetch</B> calls
+ <B>resizeterm</B> to adjust the standard screen <B>stdscr</B>, and update other
+ data such as <B>LINES</B> and <B>COLS</B>.