Fixes for pty handling in gdb-mi.el and process.c.

* lisp/progmodes/gdb-mi.el (gdb): Revert 2012-04-19 change.
(gdb-inferior-io--init-proc): New function.
(gdb-init-1): Use it.
(gdb-inferior-io-sentinel): New sentinel for the gdb-inferior pty,
responsible for allocating a new pty and hooking it to gdb when
the old pty gets an EIO due to process exit.
(gdb-delchar-or-quit): New command.  Bind it in gdb-mi buffers.
(gdb-tooltip-print): Don't use obsolete tooltip-use-echo-area.
(gdb-inferior-io--maybe-delete-pty): Move into gdb-reset.

* src/process.c (wait_reading_process_output): If EIO occurs on a pty,
set the status to "failed" and ensure that sentinel is run.

* doc/lispref/processes.texi (Asynchronous Processes): Mention nil
argument to start-process.

2 files changed, 22 insertions, 10 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index 00d257e6984..18b6ce1ad64 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,3 +1,8 @@
+2012-04-20  Chong Yidong  <cyd@gnu.org>
+
+        * process.c (wait_reading_process_output): If EIO occurs on a pty,
+        set the status to "failed" and ensure that sentinel is run.
+
 2012-04-18  Glenn Morris  <rgm@gnu.org>
 
         * process.c (Fset_process_inherit_coding_system_flag)
diff --git a/src/process.c b/src/process.c
index 3ee22d270e9..f6f1ad0a6fb 100644
--- a/src/process.c
+++ b/src/process.c
@@ -4893,16 +4893,23 @@ wait_reading_process_output (int time_limit, int microsecs, int read_kbd,
                  It can't hurt.  */
               else if (nread == -1 && errno == EIO)
                 {
-                  /* Don't do anything if only a pty, with no associated
-                     process (bug#10933).  */
-                  if (XPROCESS (proc)->pid != -2) {
-                    /* Clear the descriptor now, so we only raise the signal
-                       once.  */
-                    FD_CLR (channel, &input_wait_mask);
-                    FD_CLR (channel, &non_keyboard_wait_mask);
-                    
-                    kill (getpid (), SIGCHLD);
-                  }
+                  struct Lisp_Process *p = XPROCESS (proc);
+
+                  /* Clear the descriptor now, so we only raise the
+                     signal once.  */
+                  FD_CLR (channel, &input_wait_mask);
+                  FD_CLR (channel, &non_keyboard_wait_mask);
+
+                  if (p->pid == -2)
+                    {
+                      /* If the EIO occurs on a pty, sigchld_handler's
+                         wait3() will not find the process object to
+                         delete.  Do it here.  */
+                      p->tick = ++process_tick;
+                      p->status = Qfailed;
+                    }
+                  else
+                    kill (getpid (), SIGCHLD);
                 }
 #endif /* HAVE_PTYS */
               /* If we can detect process termination, don't consider the