From cea15c1a198ea9dc40241a63195de0764e376793 Mon Sep 17 00:00:00 2001
From: Chris Hanson <org/chris-hanson/cph>
Date: Thu, 14 Mar 1991 04:23:26 +0000
Subject: [PATCH] * New primitives `process-hangup' and `pty-master-hangup'
 support   sending of SIGHUP to subprocesses.

* Bug fixes for channel registering and selection.
---
 v7/src/microcode/osproc.h       |  3 +-
 v7/src/microcode/osterm.h       |  3 +-
 v7/src/microcode/prosio.c       |  4 +--
 v7/src/microcode/prosproc.c     |  6 +++-
 v7/src/microcode/prosterm.c     | 43 +++++++++++++----------
 v7/src/microcode/unxutl/ymkfile |  6 ++--
 v7/src/microcode/uxio.c         | 61 ++++++++++++++++++++++++--------
 v7/src/microcode/uxproc.c       | 18 ++++++++--
 v7/src/microcode/uxterm.c       | 10 ++++--
 v7/src/microcode/version.h      |  4 +--
 v7/src/microcode/x11base.c      | 62 +++++++++++++++++----------------
 v8/src/microcode/version.h      |  4 +--
 12 files changed, 144 insertions(+), 80 deletions(-)

diff --git a/v7/src/microcode/osproc.h b/v7/src/microcode/osproc.h
index cded37efa..5938ffd47 100644
--- a/v7/src/microcode/osproc.h
+++ b/v7/src/microcode/osproc.h
@@ -1,6 +1,6 @@
 /* -*-C-*-
 
-$Header: /Users/cph/tmp/foo/mit-scheme/mit-scheme/v7/src/microcode/osproc.h,v 1.4 1991/03/11 23:42:38 cph Exp $
+$Header: /Users/cph/tmp/foo/mit-scheme/mit-scheme/v7/src/microcode/osproc.h,v 1.5 1991/03/14 04:22:35 cph Exp $
 
 Copyright (c) 1990-91 Massachusetts Institute of Technology
 
@@ -116,6 +116,7 @@ extern void EXFUN (OS_process_kill, (Tprocess process));
 extern void EXFUN (OS_process_stop, (Tprocess process));
 extern void EXFUN (OS_process_interrupt, (Tprocess process));
 extern void EXFUN (OS_process_quit, (Tprocess process));
+extern void EXFUN (OS_process_hangup, (Tprocess process));
 
 extern void EXFUN (OS_process_continue_background, (Tprocess process));
 extern void EXFUN (OS_process_continue_foreground, (Tprocess process));
diff --git a/v7/src/microcode/osterm.h b/v7/src/microcode/osterm.h
index 1884fa778..35e151550 100644
--- a/v7/src/microcode/osterm.h
+++ b/v7/src/microcode/osterm.h
@@ -1,6 +1,6 @@
 /* -*-C-*-
 
-$Header: /Users/cph/tmp/foo/mit-scheme/mit-scheme/v7/src/microcode/osterm.h,v 1.6 1991/03/08 01:41:34 cph Exp $
+$Header: /Users/cph/tmp/foo/mit-scheme/mit-scheme/v7/src/microcode/osterm.h,v 1.7 1991/03/14 04:22:41 cph Exp $
 
 Copyright (c) 1990-91 Massachusetts Institute of Technology
 
@@ -64,5 +64,6 @@ extern void EXFUN (OS_pty_master_stop, (Tchannel channel));
 extern void EXFUN (OS_pty_master_continue, (Tchannel channel));
 extern void EXFUN (OS_pty_master_interrupt, (Tchannel channel));
 extern void EXFUN (OS_pty_master_quit, (Tchannel channel));
+extern void EXFUN (OS_pty_master_hangup, (Tchannel channel));
 
 #endif /* SCM_OSTERM_H */
diff --git a/v7/src/microcode/prosio.c b/v7/src/microcode/prosio.c
index 0db50638d..c5e4b55d8 100644
--- a/v7/src/microcode/prosio.c
+++ b/v7/src/microcode/prosio.c
@@ -1,6 +1,6 @@
 /* -*-C-*-
 
-$Header: /Users/cph/tmp/foo/mit-scheme/mit-scheme/v7/src/microcode/prosio.c,v 1.5 1991/03/11 23:42:45 cph Exp $
+$Header: /Users/cph/tmp/foo/mit-scheme/mit-scheme/v7/src/microcode/prosio.c,v 1.6 1991/03/14 04:22:45 cph Exp $
 
 Copyright (c) 1987-91 Massachusetts Institute of Technology
 
@@ -234,7 +234,7 @@ DEFINE_PRIMITIVE ("CHANNEL-UNREGISTER", Prim_channel_unregister, 1, 1,
 DEFINE_PRIMITIVE ("CHANNEL-SELECT-THEN-READ", Prim_channel_select_then_read, 4, 4,
   "Like CHANNEL-READ, but also watches registered input channels.\n\
 If there is no input on CHANNEL, but there is input on some other registered\n\
-channel, this procedure returns #T.")
+channel or some subprocess status changes, this procedure returns #T.")
 {
   PRIMITIVE_HEADER (4);
   CHECK_ARG (2, STRING_P);
diff --git a/v7/src/microcode/prosproc.c b/v7/src/microcode/prosproc.c
index 61d816240..6c226d96d 100644
--- a/v7/src/microcode/prosproc.c
+++ b/v7/src/microcode/prosproc.c
@@ -1,6 +1,6 @@
 /* -*-C-*-
 
-$Header: /Users/cph/tmp/foo/mit-scheme/mit-scheme/v7/src/microcode/prosproc.c,v 1.7 1991/03/11 23:42:52 cph Exp $
+$Header: /Users/cph/tmp/foo/mit-scheme/mit-scheme/v7/src/microcode/prosproc.c,v 1.8 1991/03/14 04:22:50 cph Exp $
 
 Copyright (c) 1990-91 Massachusetts Institute of Technology
 
@@ -336,6 +336,10 @@ DEFINE_PRIMITIVE ("PROCESS-QUIT", Prim_process_quit, 1, 1,
   "Sends the quit signal to process PROCESS-NUMBER (unix SIGQUIT).")
      PROCESS_SIGNALLING_PRIMITIVE (OS_process_quit)
 
+DEFINE_PRIMITIVE ("PROCESS-HANGUP", Prim_process_hangup, 1, 1,
+  "Sends the hangup signal to process PROCESS-NUMBER (unix SIGHUP).")
+     PROCESS_SIGNALLING_PRIMITIVE (OS_process_hangup)
+
 DEFINE_PRIMITIVE ("PROCESS-STOP", Prim_process_stop, 1, 1,
   "Stops process PROCESS-NUMBER (unix SIGTSTP).")
      PROCESS_SIGNALLING_PRIMITIVE (OS_process_stop)
diff --git a/v7/src/microcode/prosterm.c b/v7/src/microcode/prosterm.c
index 7de200135..359265d10 100644
--- a/v7/src/microcode/prosterm.c
+++ b/v7/src/microcode/prosterm.c
@@ -1,6 +1,6 @@
 /* -*-C-*-
 
-$Header: /Users/cph/tmp/foo/mit-scheme/mit-scheme/v7/src/microcode/prosterm.c,v 1.8 1991/03/08 01:41:38 cph Exp $
+$Header: /Users/cph/tmp/foo/mit-scheme/mit-scheme/v7/src/microcode/prosterm.c,v 1.9 1991/03/14 04:22:54 cph Exp $
 
 Copyright (c) 1990-91 Massachusetts Institute of Technology
 
@@ -49,6 +49,15 @@ DEFUN (arg_terminal, (argument_number), int argument_number)
   return (channel);
 }
 
+static Tchannel
+DEFUN (arg_pty_master, (arg), unsigned int arg)
+{
+  Tchannel channel = (arg_channel (1));
+  if ((OS_channel_type (channel)) != channel_type_pty_master)
+    error_bad_range_arg (1);
+  return (channel);
+}
+
 DEFINE_PRIMITIVE ("TERMINAL-GET-ISPEED", Prim_terminal_get_ispeed, 1, 1, 0)
 {
   PRIMITIVE_HEADER (1);
@@ -81,12 +90,6 @@ DEFINE_PRIMITIVE ("BAUD-RATE->INDEX", Prim_baud_rate_to_index, 1, 1, 0)
   }
 }
 
-DEFINE_PRIMITIVE ("OS-JOB-CONTROL?", Prim_os_job_control_p, 0, 0, 0)
-{
-  PRIMITIVE_HEADER (0);
-  PRIMITIVE_RETURN (BOOLEAN_TO_OBJECT (OS_job_control_p ()));
-}
-
 DEFINE_PRIMITIVE ("TERMINAL-GET-STATE", Prim_terminal_get_state, 1, 1, 0)
 {
   PRIMITIVE_HEADER (1);
@@ -109,7 +112,7 @@ DEFINE_PRIMITIVE ("TERMINAL-SET-STATE", Prim_terminal_set_state, 2, 2, 0)
   }
   PRIMITIVE_RETURN (UNSPECIFIC);
 }
-
+
 DEFINE_PRIMITIVE ("TERMINAL-COOKED-OUTPUT?", Prim_terminal_cooked_output_p, 1, 1,
   "Return #F iff TERMINAL is not in cooked output mode.")
 {
@@ -133,7 +136,7 @@ DEFINE_PRIMITIVE ("TERMINAL-COOKED-OUTPUT", Prim_terminal_cooked_output, 1, 1,
   OS_terminal_cooked_output (arg_terminal (1));
   PRIMITIVE_RETURN (UNSPECIFIC);
 }
-
+
 DEFINE_PRIMITIVE ("TERMINAL-BUFFERED?", Prim_terminal_buffered_p, 1, 1,
   "Return #F iff TERMINAL is not in buffered mode.")
 {
@@ -181,6 +184,12 @@ DEFINE_PRIMITIVE ("TERMINAL-DRAIN-OUTPUT", Prim_terminal_drain_output, 1, 1,
   OS_terminal_drain_output (arg_terminal (1));
   PRIMITIVE_RETURN (UNSPECIFIC);
 }
+
+DEFINE_PRIMITIVE ("OS-JOB-CONTROL?", Prim_os_job_control_p, 0, 0, 0)
+{
+  PRIMITIVE_HEADER (0);
+  PRIMITIVE_RETURN (BOOLEAN_TO_OBJECT (OS_job_control_p ()));
+}
 
 DEFINE_PRIMITIVE ("HAVE-PTYS?", Prim_have_ptys_p, 0, 0, 0)
 {
@@ -211,15 +220,6 @@ Returns a vector #(CHANNEL MASTER-NAME SLAVE-NAME).")
   }
 }
 
-static Tchannel
-DEFUN (arg_pty_master, (arg), unsigned int arg)
-{
-  Tchannel channel = (arg_channel (1));
-  if ((OS_channel_type (channel)) != channel_type_pty_master)
-    error_bad_range_arg (1);
-  return (channel);
-}
-
 DEFINE_PRIMITIVE ("PTY-MASTER-SEND-SIGNAL", Prim_pty_master_send_signal, 2, 2,
   "Send a signal to PTY-MASTER; second arg says which one.")
 {
@@ -263,3 +263,10 @@ DEFINE_PRIMITIVE ("PTY-MASTER-QUIT", Prim_pty_master_quit, 1, 1, 0)
   OS_pty_master_quit (arg_pty_master (1));
   PRIMITIVE_RETURN (UNSPECIFIC);
 }
+
+DEFINE_PRIMITIVE ("PTY-MASTER-HANGUP", Prim_pty_master_hangup, 1, 1, 0)
+{
+  PRIMITIVE_HEADER (1);
+  OS_pty_master_hangup (arg_pty_master (1));
+  PRIMITIVE_RETURN (UNSPECIFIC);
+}
diff --git a/v7/src/microcode/unxutl/ymkfile b/v7/src/microcode/unxutl/ymkfile
index 0f42de8ea..9b6937718 100644
--- a/v7/src/microcode/unxutl/ymkfile
+++ b/v7/src/microcode/unxutl/ymkfile
@@ -1,6 +1,6 @@
 /* -*-C-*-
 
-$Header: /Users/cph/tmp/foo/mit-scheme/mit-scheme/v7/src/microcode/unxutl/Attic/ymkfile,v 1.41 1991/02/26 21:33:51 cph Exp $
+$Header: /Users/cph/tmp/foo/mit-scheme/mit-scheme/v7/src/microcode/unxutl/Attic/ymkfile,v 1.42 1991/03/14 04:23:26 cph Exp $
 
 Copyright (c) 1989-91 Massachusetts Institute of Technology
 
@@ -626,7 +626,7 @@ dmpwrld.o : scheme.touch prims.h ux.h osfs.h \
 	unexec.c unexhp9k800.c getpagesize.h
 
 x11base.o x11graph.o x11term.o starbasex.o : scheme.touch prims.h x11.h
-x11base.o : ux.h
+x11base.o : ux.h osio.h uxselect.h
 starbase.o : scheme.touch prims.h
 
 Sgraph.o Sgraph_xt.o SgX.o : scheme.touch prims.h Sgraph.h
@@ -652,7 +652,7 @@ uxctty.o : osctty.h
 uxenv.o : osenv.h
 uxfile.o : osfile.h osio.h uxio.h
 uxfs.o : osfs.h
-uxio.o : osio.h uxio.h
+uxio.o : osio.h uxio.h uxselect.h
 uxproc.o : osproc.h uxproc.h osio.h uxio.h osterm.h
 uxsig.o : ossig.h osctty.h ostty.h uxtrap.h uxutil.h critsec.h
 uxsock.o : uxsock.h osio.h uxio.h
diff --git a/v7/src/microcode/uxio.c b/v7/src/microcode/uxio.c
index b550e9bbd..4adf38fd9 100644
--- a/v7/src/microcode/uxio.c
+++ b/v7/src/microcode/uxio.c
@@ -1,6 +1,6 @@
 /* -*-C-*-
 
-$Header: /Users/cph/tmp/foo/mit-scheme/mit-scheme/v7/src/microcode/uxio.c,v 1.10 1991/03/11 23:43:02 cph Exp $
+$Header: /Users/cph/tmp/foo/mit-scheme/mit-scheme/v7/src/microcode/uxio.c,v 1.11 1991/03/14 04:22:59 cph Exp $
 
 Copyright (c) 1990-91 Massachusetts Institute of Technology
 
@@ -34,6 +34,7 @@ MIT in each case. */
 
 #include "ux.h"
 #include "uxio.h"
+#include "uxselect.h"
 
 size_t OS_channel_table_size;
 struct channel * channel_table;
@@ -123,7 +124,8 @@ DEFUN (OS_channel_close, (channel), Tchannel channel)
 {
   if (! (CHANNEL_INTERNAL (channel)))
     {
-      OS_channel_unregister (channel);
+      if (CHANNEL_REGISTERED (channel))
+	OS_channel_unregister (channel);
       STD_VOID_SYSTEM_CALL
 	(syscall_close, (UX_close (CHANNEL_DESCRIPTOR (channel))));
       MARK_CHANNEL_CLOSED (channel);
@@ -135,7 +137,8 @@ DEFUN (OS_channel_close_noerror, (channel), Tchannel channel)
 {
   if (! (CHANNEL_INTERNAL (channel)))
     {
-      OS_channel_unregister (channel);
+      if (CHANNEL_REGISTERED (channel))
+	OS_channel_unregister (channel);
       UX_close (CHANNEL_DESCRIPTOR (channel));
       MARK_CHANNEL_CLOSED (channel);
     }
@@ -355,21 +358,43 @@ DEFUN (OS_channel_unregister, (channel), Tchannel channel)
       (CHANNEL_REGISTERED (channel)) = 0;
     }
 }
-
-int
+
+enum select_input
 DEFUN (UX_select_input, (fd, blockp), int fd AND int blockp)
 {
 #ifdef HAVE_SELECT
+  extern int EXFUN (UX_process_any_status_change, (void));
+  int status_change_p;
   int nfds;
   SELECT_TYPE readable = input_descriptors;
   FD_SET (fd, (&readable));
-  STD_UINT_SYSTEM_CALL
-    (syscall_select,
-     nfds,
-     (select (FD_SETSIZE, (&readable), 0, 0, (blockp ? 0 : (&zero_timeout)))));
-  return ((nfds > 0) && (! (FD_ISSET (fd, (&readable)))));
+  while (1)
+    {
+      status_change_p = 0;
+      INTERRUPTABLE_EXTENT
+	(nfds,
+	 ((status_change_p = (UX_process_any_status_change ()))
+	  ? ((errno = EINTR), (-1))
+	  : (select (FD_SETSIZE, (&readable), 0, 0,
+		     (blockp ? 0 : (&zero_timeout))))));
+      if (nfds > 0)
+	return
+	  ((FD_ISSET (fd, (&readable)))
+	   ? select_input_argument
+	   : select_input_other);
+      else if (nfds == 0)
+	{
+	  if (!blockp)
+	    return (select_input_none);
+	}
+      else if (errno != EINTR)
+	error_system_call (errno, syscall_select);
+      else if (status_change_p)
+	return (select_input_process_status);
+      deliver_pending_interrupts ();
+    }
 #else
-  return (0);
+  return (select_input_argument);
 #endif
 }
 
@@ -380,10 +405,16 @@ DEFUN (OS_channel_select_then_read, (channel, buffer, nbytes),
        size_t nbytes)
 {
 #ifdef HAVE_SELECT
-  if ((OS_channels_registered > ((CHANNEL_REGISTERED (channel)) ? 1 : 0))
-      && (UX_select_input ((CHANNEL_DESCRIPTOR (channel)),
-			   (CHANNEL_NONBLOCKING (channel)))))
-    return (-2);
+  if (OS_channels_registered > ((CHANNEL_REGISTERED (channel)) ? 1 : 0))
+    switch (UX_select_input ((CHANNEL_DESCRIPTOR (channel)),
+			     (! (CHANNEL_NONBLOCKING (channel)))))
+      {
+      case select_input_none:
+	return (-1);
+      case select_input_other:
+      case select_input_process_status:
+	return (-2);
+      }
 #endif
   return (OS_channel_read (channel, buffer, nbytes));
 }
diff --git a/v7/src/microcode/uxproc.c b/v7/src/microcode/uxproc.c
index 53b71b159..92fea1d84 100644
--- a/v7/src/microcode/uxproc.c
+++ b/v7/src/microcode/uxproc.c
@@ -1,6 +1,6 @@
 /* -*-C-*-
 
-$Header: /Users/cph/tmp/foo/mit-scheme/mit-scheme/v7/src/microcode/uxproc.c,v 1.9 1991/03/11 23:43:12 cph Exp $
+$Header: /Users/cph/tmp/foo/mit-scheme/mit-scheme/v7/src/microcode/uxproc.c,v 1.10 1991/03/14 04:23:03 cph Exp $
 
 Copyright (c) 1990-91 Massachusetts Institute of Technology
 
@@ -422,7 +422,7 @@ DEFUN (OS_make_subprocess,
  kill_child:
   _exit (1);
 }
-
+
 #define DEFUN_PROCESS_ACCESSOR(name, result_type, accessor)		\
 result_type								\
 DEFUN (name, (process), Tprocess process)				\
@@ -435,7 +435,7 @@ DEFUN_PROCESS_ACCESSOR (OS_process_status, enum process_status, PROCESS_STATUS)
 DEFUN_PROCESS_ACCESSOR (OS_process_reason, unsigned short, PROCESS_REASON)
 DEFUN_PROCESS_ACCESSOR
   (OS_process_jc_status, enum process_jc_status, PROCESS_JC_STATUS)
-
+
 int
 DEFUN (OS_process_valid_p, (process), Tprocess process)
 {
@@ -502,6 +502,12 @@ DEFUN_VOID (OS_process_status_sync_all)
     return (result);
   }
 }
+
+int
+DEFUN_VOID (UX_process_any_status_change)
+{
+  return (process_tick != sync_tick);
+}
 
 void
 DEFUN (OS_process_send_signal, (process, sig), Tprocess process AND int sig)
@@ -538,6 +544,12 @@ DEFUN (OS_process_quit, (process), Tprocess process)
   OS_process_send_signal (process, SIGQUIT);
 }
 
+void
+DEFUN (OS_process_hangup, (process), Tprocess process)
+{
+  OS_process_send_signal (process, SIGHUP);
+}
+
 void
 DEFUN (OS_process_continue_background, (process), Tprocess process)
 {
diff --git a/v7/src/microcode/uxterm.c b/v7/src/microcode/uxterm.c
index cdcaf3ae1..591ac6d07 100644
--- a/v7/src/microcode/uxterm.c
+++ b/v7/src/microcode/uxterm.c
@@ -1,6 +1,6 @@
 /* -*-C-*-
 
-$Header: /Users/cph/tmp/foo/mit-scheme/mit-scheme/v7/src/microcode/uxterm.c,v 1.12 1991/03/08 01:41:42 cph Exp $
+$Header: /Users/cph/tmp/foo/mit-scheme/mit-scheme/v7/src/microcode/uxterm.c,v 1.13 1991/03/14 04:23:08 cph Exp $
 
 Copyright (c) 1990-1 Massachusetts Institute of Technology
 
@@ -550,7 +550,7 @@ DEFUN (OS_open_pty_master, (master_fd, master_fname),
   error_external_return ();
   return (0);
 }
-
+
 void
 DEFUN (OS_pty_master_send_signal, (channel, sig), Tchannel channel AND int sig)
 {
@@ -624,3 +624,9 @@ DEFUN (OS_pty_master_quit, (channel), Tchannel channel)
 {
   OS_pty_master_send_signal (channel, SIGQUIT);
 }
+
+void
+DEFUN (OS_pty_master_hangup, (channel), Tchannel channel)
+{
+  OS_pty_master_send_signal (channel, SIGHUP);
+}
diff --git a/v7/src/microcode/version.h b/v7/src/microcode/version.h
index dda3e2a28..7c556fa67 100644
--- a/v7/src/microcode/version.h
+++ b/v7/src/microcode/version.h
@@ -1,6 +1,6 @@
 /* -*-C-*-
 
-$Header: /Users/cph/tmp/foo/mit-scheme/mit-scheme/v7/src/microcode/Attic/version.h,v 11.67 1991/03/11 23:43:21 cph Exp $
+$Header: /Users/cph/tmp/foo/mit-scheme/mit-scheme/v7/src/microcode/Attic/version.h,v 11.68 1991/03/14 04:23:15 cph Exp $
 
 Copyright (c) 1988-91 Massachusetts Institute of Technology
 
@@ -46,5 +46,5 @@ MIT in each case. */
 #define VERSION		11
 #endif
 #ifndef SUBVERSION
-#define SUBVERSION	67
+#define SUBVERSION	68
 #endif
diff --git a/v7/src/microcode/x11base.c b/v7/src/microcode/x11base.c
index 08b2f686b..88bb21935 100644
--- a/v7/src/microcode/x11base.c
+++ b/v7/src/microcode/x11base.c
@@ -1,6 +1,6 @@
 /* -*-C-*-
 
-$Header: /Users/cph/tmp/foo/mit-scheme/mit-scheme/v7/src/microcode/x11base.c,v 1.16 1991/03/11 23:43:28 cph Exp $
+$Header: /Users/cph/tmp/foo/mit-scheme/mit-scheme/v7/src/microcode/x11base.c,v 1.17 1991/03/14 04:23:20 cph Exp $
 
 Copyright (c) 1989-91 Massachusetts Institute of Technology
 
@@ -37,6 +37,8 @@ MIT in each case. */
 #include "scheme.h"
 #include "prims.h"
 #include "ux.h"
+#include "osio.h"
+#include "uxselect.h"
 #include "x11.h"
 
 int x_debug = 0;
@@ -699,8 +701,8 @@ DEFUN (x_event_to_object, (event), XEvent * event)
    entry that reads events -- or else that all other event readers
    cooperate with this strategy.  */
 
-extern unsigned int OS_channels_registered;
-extern int EXFUN (UX_select_input, (int fd, int blockp));
+/* The time_limit argument is currently ignored, because Edwin doesn't
+   use it.  */
 
 static SCHEME_OBJECT
 DEFUN (xd_process_events, (xd, time_limit_p, time_limit),
@@ -708,38 +710,38 @@ DEFUN (xd_process_events, (xd, time_limit_p, time_limit),
        int time_limit_p AND
        unsigned long time_limit)
 {
-  unsigned int events_queued = 0;
   Display * display = (XD_DISPLAY (xd));
+  int do_select = (OS_channels_registered > 0);
+  unsigned int events_queued;
   if (XD_CACHED_EVENT_P (xd))
-    goto restart;
+    {
+      events_queued = (XEventsQueued (display, QueuedAlready));
+      goto restart;
+    }
+  events_queued =
+    (do_select ? (XEventsQueued (display, QueuedAlready))
+     : time_limit_p ? (XEventsQueued (display, QueuedAfterReading))
+     : 0);
   while (1)
     {
-      extern unsigned long EXFUN (OS_real_time_clock, (void));
       XEvent event;
-      if (time_limit_p || (OS_channels_registered > 0))
-	{
-	  if (events_queued > 0)
-	    events_queued -= 1;
-	  else
-	    while (1)
-	      {
-		events_queued = (XEventsQueued (display, QueuedAfterReading));
-		if (events_queued > 0)
-		  {
-		    events_queued -= 1;
-		    break;
-		  }
-		if (time_limit_p && ((OS_real_time_clock ()) >= time_limit))
-		  return (SHARP_F);
-		if (UX_select_input ((ConnectionNumber (display)),
-				     (!time_limit_p)))
-		  /* No input is available from the display, but some
-		     other registered input channel has input.  Return a
-		     special value immediately so that input can be
-		     processed.  */
-		  return (SHARP_T);
-	      }
-	}
+      if (events_queued > 0)
+	events_queued -= 1;
+      else if (do_select)
+	switch (UX_select_input ((ConnectionNumber (display)),
+				 (!time_limit_p)))
+	  {
+	  case select_input_none:
+	    return (SHARP_F);
+	  case select_input_other:
+	  case select_input_process_status:
+	    return (SHARP_T);
+	  case select_input_argument:
+	    events_queued = (XEventsQueued (display, QueuedAfterReading));
+	    continue;
+	  }
+      else if (time_limit_p)
+	return (SHARP_F);
       XNextEvent (display, (&event));
       if ((event . type) == KeymapNotify)
 	continue;
diff --git a/v8/src/microcode/version.h b/v8/src/microcode/version.h
index 15b63b0b3..5f8a8e134 100644
--- a/v8/src/microcode/version.h
+++ b/v8/src/microcode/version.h
@@ -1,6 +1,6 @@
 /* -*-C-*-
 
-$Header: /Users/cph/tmp/foo/mit-scheme/mit-scheme/v8/src/microcode/version.h,v 11.67 1991/03/11 23:43:21 cph Exp $
+$Header: /Users/cph/tmp/foo/mit-scheme/mit-scheme/v8/src/microcode/version.h,v 11.68 1991/03/14 04:23:15 cph Exp $
 
 Copyright (c) 1988-91 Massachusetts Institute of Technology
 
@@ -46,5 +46,5 @@ MIT in each case. */
 #define VERSION		11
 #endif
 #ifndef SUBVERSION
-#define SUBVERSION	67
+#define SUBVERSION	68
 #endif
-- 
2.25.1