(wait_reading_process_output): Keep the descriptor

when pty is used by a non-child process, e.g., in I/O buffer of
GDB this allows inferior to be restarted.

1 files changed, 9 insertions, 4 deletions

diff --git a/src/process.c b/src/process.c
index 77ca2551e46..ed535170214 100644
--- a/src/process.c
+++ b/src/process.c
@@ -5150,11 +5150,16 @@ wait_reading_process_output (time_limit, microsecs, read_kbd, do_display,
                  It can't hurt.  */
               else if (nread == -1 && errno == EIO)
                 {
-                  /* Clear the descriptor now, so we only raise the signal once.  */
-                  FD_CLR (channel, &input_wait_mask);
-                  FD_CLR (channel, &non_keyboard_wait_mask);
+                  /* Clear the descriptor now, so we only raise the
+                     signal once.  Don't do this is `process' is only
+                     a pty.  */
+                  if (XPROCESS (proc)->pid != -2)
+                    {
+                      FD_CLR (channel, &input_wait_mask);
+                      FD_CLR (channel, &non_keyboard_wait_mask);
 
-                  kill (getpid (), SIGCHLD);
+                      kill (getpid (), SIGCHLD);
+                    }
                 }
 #endif /* HAVE_PTYS */
               /* If we can detect process termination, don't consider the process