Simplify SIGIO usage.

The code that dealt with SIGIO was crufty and confusing, e.g., it
played tricks like "#undef SIGIO" but these tricks were not used
consistently.  Simplify mostly by not #undeffing standard symbols,
e.g., use "defined USABLE_SIGIO" (our symbol, which we can define
or not as we please) rather than "defined SIGIO" (standard symbol
that we probably shouldn't #undef).
* configure.ac (NO_TERMIO, BROKEN_FIONREAD, BROKEN_SIGAIO)
(BROKEN_SIGPOLL, BROKEN_SIGPTY): Remove.
(USABLE_FIONREAD, USABLE_SIGIO): New symbols.  All uses of
'defined SIGIO' replaced with 'defined USABLE_SIGIO', with no need
to #undef SIGIO now (which was error-prone).  Likewise, all uses
of 'defined FIONREAD' replaced with 'defined USABLE_FIONREAD'.
* src/admin/CPP_DEFINES (BROKEN_SIGAIO, BROKEN_SIGIO, BROKEN_SIGPOLL)
(BROKEN_SIGPTY, NO_TERMIO): Remove.
* src/conf_post.h [USG5_4]: Do not include <sys/wait.h> here.
Modules that need it can include it.
[USG5_4 && emacs]: Likewise, do not include the streams stuff here.
* src/dispextern.h (ignore_sigio): New decl.
* src/emacs.c (shut_down_emacs): Invoke unrequest_sigio
unconditionally, since it's now a no-op if !USABLE_SIGIO.
* src/emacs.c (shut_down_emacs):
* src/keyboard.c (kbd_buffer_store_event_hold):
Use ignore_sigio rather than invoking 'signal' directly.
* src/keyboard.c (USABLE_FIONREAD && USG5_4): Include <sys/filio.h>,
for FIONREAD.
(FIONREAD, SIGIO): Do not #undef.
(tty_read_avail_input): Use #error rather than a syntax error.
* src/process.c [USG5_4]: Include <sys/stream.h> and <sys/stropts.h>,
for I_PIPE, used by SETUP_SLAVE_PTY.
(DATAGRAM_SOCKETS): Simplify defn, based on USABLE_FIONREAD.
* src/sysdep.c (croak): Remove; no longer needed.  This bit of
temporary code, with Fred N. Fish's comment that it's temporary,
has been in Emacs since at least 1992!
(init_sigio, reset_sigio, request_sigio, unrequest_sigio):
Arrange for them to be no-ops in all cases when ! USABLE_SIGIO.
* src/syssignal.h (croak): Remove decl.
(SIGIO, SIGPOO, SIGAIO, SIGPTY): Do not #undef; that's too fragile.
* src/systty.h [!NO_TERMIO]: Do not include <termio.h>; no longer needed
now that we're termios-only.
(FIONREAD, ASYNC) [BROKEN_FIONREAD]: Do not #undef.
* src/term.c (dissociate_if_controlling_tty): Use #error rather than
a run-time error.

Fixes: debbugs:12408

1 files changed, 36 insertions, 0 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index 29e8ea4232e..c8588b973f8 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,5 +1,41 @@
 2012-09-13  Paul Eggert  <eggert@cs.ucla.edu>
 
+        Simplify SIGIO usage (Bug#12408).
+        The code that dealt with SIGIO was crufty and confusing, e.g., it
+        played tricks like "#undef SIGIO" but these tricks were not used
+        consistently.  Simplify mostly by not #undeffing standard symbols,
+        e.g., use "defined USABLE_SIGIO" (our symbol, which we can define
+        or not as we please) rather than "defined SIGIO" (standard symbol
+        that we probably shouldn't #undef).
+        * conf_post.h [USG5_4]: Do not include <sys/wait.h> here.
+        Modules that need it can include it.
+        [USG5_4 && emacs]: Likewise, do not include the streams stuff here.
+        * dispextern.h (ignore_sigio): New decl.
+        * emacs.c (shut_down_emacs): Invoke unrequest_sigio
+        unconditionally, since it's now a no-op if !USABLE_SIGIO.
+        * emacs.c (shut_down_emacs):
+        * keyboard.c (kbd_buffer_store_event_hold):
+        Use ignore_sigio rather than invoking 'signal' directly.
+        * keyboard.c (USABLE_FIONREAD && USG5_4): Include <sys/filio.h>,
+        for FIONREAD.
+        (FIONREAD, SIGIO): Do not #undef.
+        (tty_read_avail_input): Use #error rather than a syntax error.
+        * process.c [USG5_4]: Include <sys/stream.h> and <sys/stropts.h>,
+        for I_PIPE, used by SETUP_SLAVE_PTY.
+        (DATAGRAM_SOCKETS): Simplify defn, based on USABLE_FIONREAD.
+        * sysdep.c (croak): Remove; no longer needed.  This bit of
+        temporary code, with Fred N. Fish's comment that it's temporary,
+        has been in Emacs since at least 1992!
+        (init_sigio, reset_sigio, request_sigio, unrequest_sigio):
+        Arrange for them to be no-ops in all cases when ! USABLE_SIGIO.
+        * syssignal.h (croak): Remove decl.
+        (SIGIO, SIGPOO, SIGAIO, SIGPTY): Do not #undef; that's too fragile.
+        * systty.h [!NO_TERMIO]: Do not include <termio.h>; no longer needed
+        now that we're termios-only.
+        (FIONREAD, ASYNC) [BROKEN_FIONREAD]: Do not #undef.
+        * term.c (dissociate_if_controlling_tty): Use #error rather than
+        a run-time error.
+
         Work around GCC and GNOME bugs when --enable-gcc-warnings.
         * emacsgtkfixed.c (G_STATIC_ASSERT): Redefine to use 'verify',
         to work around GNOME bug 683906.