diff --git a/gdb/breakpoint.c b/gdb/breakpoint.c
index afd9065..1fad0d1 100644
--- a/gdb/breakpoint.c
+++ b/gdb/breakpoint.c
@@ -4720,7 +4720,7 @@ bpstat_do_actions_1 (bpstat *bsp)
 
       if (breakpoint_proceeded)
 	{
-	  if (interpreter_async)
+	  if (current_ui->async)
 	    /* If we are in async mode, then the target might be still
 	       running, not stopped at any breakpoint, so nothing for
 	       us to do here -- just return to the event loop.  */
diff --git a/gdb/cli/cli-script.c b/gdb/cli/cli-script.c
index 7302330..5fc01b3 100644
--- a/gdb/cli/cli-script.c
+++ b/gdb/cli/cli-script.c
@@ -379,8 +379,8 @@ execute_user_command (struct cmd_list_element *c, char *args)
      not confused with Insight.  */
   in_user_command = 1;
 
-  make_cleanup_restore_integer (&interpreter_async);
-  interpreter_async = 0;
+  make_cleanup_restore_integer (&current_ui->async);
+  current_ui->async = 0;
 
   command_nest_depth++;
   while (cmdlines)
@@ -661,8 +661,8 @@ while_command (char *arg, int from_tty)
   if (command == NULL)
     return;
 
-  old_chain = make_cleanup_restore_integer (&interpreter_async);
-  interpreter_async = 0;
+  old_chain = make_cleanup_restore_integer (&current_ui->async);
+  current_ui->async = 0;
 
   execute_control_command_untraced (command);
   free_command_lines (&command);
@@ -685,8 +685,8 @@ if_command (char *arg, int from_tty)
   if (command == NULL)
     return;
 
-  old_chain = make_cleanup_restore_integer (&interpreter_async);
-  interpreter_async = 0;
+  old_chain = make_cleanup_restore_integer (&current_ui->async);
+  current_ui->async = 0;
 
   execute_control_command_untraced (command);
   free_command_lines (&command);
@@ -1688,8 +1688,8 @@ script_from_file (FILE *stream, const char *file)
   source_line_number = 0;
   source_file_name = file;
 
-  make_cleanup_restore_integer (&interpreter_async);
-  interpreter_async = 0;
+  make_cleanup_restore_integer (&current_ui->async);
+  current_ui->async = 0;
 
   {
 
diff --git a/gdb/compile/compile.c b/gdb/compile/compile.c
index 77b4137..0c4a738 100644
--- a/gdb/compile/compile.c
+++ b/gdb/compile/compile.c
@@ -18,7 +18,7 @@
    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
 
 #include "defs.h"
-#include "interps.h"
+#include "top.h"
 #include "ui-out.h"
 #include "command.h"
 #include "cli/cli-script.h"
@@ -91,8 +91,8 @@ compile_file_command (char *arg, int from_tty)
   char *buffer;
   struct cleanup *cleanup;
 
-  cleanup = make_cleanup_restore_integer (&interpreter_async);
-  interpreter_async = 0;
+  cleanup = make_cleanup_restore_integer (&current_ui->async);
+  current_ui->async = 0;
 
   /* Check the user did not just <enter> after command.  */
   if (arg == NULL)
@@ -133,8 +133,8 @@ compile_code_command (char *arg, int from_tty)
   struct cleanup *cleanup;
   enum compile_i_scope_types scope = COMPILE_I_SIMPLE_SCOPE;
 
-  cleanup = make_cleanup_restore_integer (&interpreter_async);
-  interpreter_async = 0;
+  cleanup = make_cleanup_restore_integer (&current_ui->async);
+  current_ui->async = 0;
 
   if (arg != NULL && check_raw_argument (&arg))
     {
@@ -187,8 +187,8 @@ compile_print_command (char *arg_param, int from_tty)
   enum compile_i_scope_types scope = COMPILE_I_PRINT_ADDRESS_SCOPE;
   struct format_data fmt;
 
-  cleanup = make_cleanup_restore_integer (&interpreter_async);
-  interpreter_async = 0;
+  cleanup = make_cleanup_restore_integer (&current_ui->async);
+  current_ui->async = 0;
 
   /* Passing &FMT as SCOPE_DATA is safe as do_module_cleanup will not
      touch the stale pointer if compile_object_run has already quit.  */
diff --git a/gdb/guile/guile.c b/gdb/guile/guile.c
index 7352b57..86964eb 100644
--- a/gdb/guile/guile.c
+++ b/gdb/guile/guile.c
@@ -27,7 +27,7 @@
 #include "cli/cli-utils.h"
 #include "command.h"
 #include "gdbcmd.h"
-#include "interps.h"
+#include "top.h"
 #include "extension-priv.h"
 #include "utils.h"
 #include "version.h"
@@ -166,8 +166,8 @@ guile_repl_command (char *arg, int from_tty)
 {
   struct cleanup *cleanup;
 
-  cleanup = make_cleanup_restore_integer (&interpreter_async);
-  interpreter_async = 0;
+  cleanup = make_cleanup_restore_integer (&current_ui->async);
+  current_ui->async = 0;
 
   arg = skip_spaces (arg);
 
@@ -199,8 +199,8 @@ guile_command (char *arg, int from_tty)
 {
   struct cleanup *cleanup;
 
-  cleanup = make_cleanup_restore_integer (&interpreter_async);
-  interpreter_async = 0;
+  cleanup = make_cleanup_restore_integer (&current_ui->async);
+  current_ui->async = 0;
 
   arg = skip_spaces (arg);
 
@@ -329,8 +329,8 @@ gdbscm_execute_gdb_command (SCM command_scm, SCM rest)
     {
       struct cleanup *inner_cleanups;
 
-      inner_cleanups = make_cleanup_restore_integer (&interpreter_async);
-      interpreter_async = 0;
+      inner_cleanups = make_cleanup_restore_integer (&current_ui->async);
+      current_ui->async = 0;
 
       prevent_dont_repeat ();
       if (to_string)
diff --git a/gdb/guile/scm-ports.c b/gdb/guile/scm-ports.c
index a7d61af..b4e8ce6 100644
--- a/gdb/guile/scm-ports.c
+++ b/gdb/guile/scm-ports.c
@@ -23,7 +23,7 @@
 
 #include "defs.h"
 #include "gdb_select.h"
-#include "interps.h"
+#include "top.h"
 #include "target.h"
 #include "guile-internal.h"
 
@@ -515,8 +515,8 @@ ioscm_with_output_to_port_worker (SCM port, SCM thunk, enum oport oport,
 
   cleanups = set_batch_flag_and_make_cleanup_restore_page_info ();
 
-  make_cleanup_restore_integer (&interpreter_async);
-  interpreter_async = 0;
+  make_cleanup_restore_integer (&current_ui->async);
+  current_ui->async = 0;
 
   port_file = ioscm_file_port_new (port);
 
diff --git a/gdb/inf-loop.c b/gdb/inf-loop.c
index 2591ae9..d006df8 100644
--- a/gdb/inf-loop.c
+++ b/gdb/inf-loop.c
@@ -61,7 +61,7 @@ inferior_event_handler (enum inferior_event_type event_type,
 
       /* When running a command list (from a user command, say), these
 	 are only run when the command list is all done.  */
-      if (interpreter_async)
+      if (current_ui->async)
 	{
 	  check_frame_language_change ();
 
diff --git a/gdb/infcall.c b/gdb/infcall.c
index 77cd931..11f5aba 100644
--- a/gdb/infcall.c
+++ b/gdb/infcall.c
@@ -560,13 +560,13 @@ run_inferior_call (struct call_thread_fsm *sm,
   ptid_t call_thread_ptid = call_thread->ptid;
   int saved_sync_execution = sync_execution;
   int was_running = call_thread->state == THREAD_RUNNING;
-  int saved_interpreter_async = interpreter_async;
+  int saved_ui_async = current_ui->async;
 
   /* Infcalls run synchronously, in the foreground.  */
   sync_execution = 1;
   /* So that we don't print the prompt prematurely in
      fetch_inferior_event.  */
-  interpreter_async = 0;
+  current_ui->async = 0;
 
   call_thread->control.in_infcall = 1;
 
@@ -601,7 +601,7 @@ run_inferior_call (struct call_thread_fsm *sm,
      again here.  In other cases, stdin will be re-enabled by
      inferior_event_handler, when an exception is thrown.  */
   sync_execution = saved_sync_execution;
-  interpreter_async = saved_interpreter_async;
+  current_ui->async = saved_ui_async;
 
   /* At this point the current thread may have changed.  Refresh
      CALL_THREAD as it could be invalid if its thread has exited.  */
diff --git a/gdb/infrun.c b/gdb/infrun.c
index 15210c9..7f0c3c9 100644
--- a/gdb/infrun.c
+++ b/gdb/infrun.c
@@ -3790,7 +3790,7 @@ wait_for_inferior (void)
 static void
 reinstall_readline_callback_handler_cleanup (void *arg)
 {
-  if (!interpreter_async)
+  if (!current_ui->async)
     {
       /* We're not going back to the top level event loop yet.  Don't
 	 install the readline callback, as it'd prep the terminal,
@@ -3977,7 +3977,7 @@ fetch_inferior_event (void *client_data)
   /* If the inferior was in sync execution mode, and now isn't,
      restore the prompt (a synchronous execution command has finished,
      and we're ready for input).  */
-  if (interpreter_async && was_sync && !sync_execution)
+  if (current_ui->async && was_sync && !sync_execution)
     observer_notify_sync_execution_done ();
 
   if (cmd_done
diff --git a/gdb/interps.c b/gdb/interps.c
index b188d08..945b830 100644
--- a/gdb/interps.c
+++ b/gdb/interps.c
@@ -39,11 +39,29 @@
 #include "top.h"		/* For command_loop.  */
 #include "continuations.h"
 
-/* True if the current interpreter in is async mode.  See interps.h
-   for more details.  This starts out disabled, until all the explicit
-   command line arguments (e.g., `gdb -ex "start" -ex "next"') are
-   processed.  */
-int interpreter_async = 0;
+/* Each UI has its own independent set of interpreters.  */
+
+struct ui_interp_info
+{
+  /* Each top level has its own independent set of interpreters.  */
+  struct interp *interp_list;
+  struct interp *current_interpreter;
+  struct interp *top_level_interpreter_ptr;
+
+  /* The interpreter that is active while `interp_exec' is active, NULL
+     at all other times.  */
+  struct interp *command_interpreter;
+};
+
+static struct ui_interp_info *
+get_current_interp_info (void)
+{
+  struct ui *ui = current_ui;
+
+  if (ui->interp_info == NULL)
+    ui->interp_info = XCNEW (struct ui_interp_info);
+  return ui->interp_info;
+}
 
 struct interp
 {
@@ -71,12 +89,6 @@ struct interp
 
 void _initialize_interpreter (void);
 
-/* Variables local to this file: */
-
-static struct interp *interp_list = NULL;
-static struct interp *current_interpreter = NULL;
-static struct interp *top_level_interpreter_ptr = NULL;
-
 /* interp_new - This allocates space for a new interpreter,
    fills the fields from the inputs, and returns a pointer to the
    interpreter.  */
@@ -104,10 +116,12 @@ interp_new (const char *name, const struct interp_procs *procs)
 void
 interp_add (struct interp *interp)
 {
+  struct ui_interp_info *ui_interp = get_current_interp_info ();
+
   gdb_assert (interp_lookup (interp->name) == NULL);
 
-  interp->next = interp_list;
-  interp_list = interp;
+  interp->next = ui_interp->interp_list;
+  ui_interp->interp_list = interp;
 }
 
 /* This sets the current interpreter to be INTERP.  If INTERP has not
@@ -127,24 +141,24 @@ interp_add (struct interp *interp)
 int
 interp_set (struct interp *interp, int top_level)
 {
-  struct interp *old_interp = current_interpreter;
+  struct ui_interp_info *ui_interp = get_current_interp_info ();
+  struct interp *old_interp = ui_interp->current_interpreter;
   int first_time = 0;
   char buffer[64];
 
   /* If we already have an interpreter, then trying to
      set top level interpreter is kinda pointless.  */
-  gdb_assert (!top_level || !current_interpreter);
-  gdb_assert (!top_level || !top_level_interpreter_ptr);
+  gdb_assert (!top_level || !ui_interp->current_interpreter);
+  gdb_assert (!top_level || !ui_interp->top_level_interpreter_ptr);
 
-  if (current_interpreter != NULL)
+  if (old_interp != NULL)
     {
       ui_out_flush (current_uiout);
-      if (current_interpreter->procs->suspend_proc
-	  && !current_interpreter->procs->suspend_proc (current_interpreter->
-							data))
+      if (old_interp->procs->suspend_proc
+	  && !old_interp->procs->suspend_proc (old_interp->data))
 	{
 	  error (_("Could not suspend interpreter \"%s\"."),
-		 current_interpreter->name);
+		 old_interp->name);
 	}
     }
   else
@@ -152,18 +166,18 @@ interp_set (struct interp *interp, int top_level)
       first_time = 1;
     }
 
-  current_interpreter = interp;
+  ui_interp->current_interpreter = interp;
   if (top_level)
-    top_level_interpreter_ptr = interp;
+    ui_interp->top_level_interpreter_ptr = interp;
 
   /* We use interpreter_p for the "set interpreter" variable, so we need
      to make sure we have a malloc'ed copy for the set command to free.  */
   if (interpreter_p != NULL
-      && strcmp (current_interpreter->name, interpreter_p) != 0)
+      && strcmp (interp->name, interpreter_p) != 0)
     {
       xfree (interpreter_p);
 
-      interpreter_p = xstrdup (current_interpreter->name);
+      interpreter_p = xstrdup (interp->name);
     }
 
   /* Run the init proc.  If it fails, try to restore the old interp.  */
@@ -209,12 +223,15 @@ interp_set (struct interp *interp, int top_level)
 struct interp *
 interp_lookup (const char *name)
 {
+  struct ui_interp_info *ui_interp = get_current_interp_info ();
   struct interp *interp;
 
   if (name == NULL || strlen (name) == 0)
     return NULL;
 
-  for (interp = interp_list; interp != NULL; interp = interp->next)
+  for (interp = ui_interp->interp_list;
+       interp != NULL;
+       interp = interp->next)
     {
       if (strcmp (interp->name, name) == 0)
 	return interp;
@@ -228,34 +245,37 @@ interp_lookup (const char *name)
 struct ui_out *
 interp_ui_out (struct interp *interp)
 {
-  if (interp != NULL)
-    return interp->procs->ui_out_proc (interp);
+  struct ui_interp_info *ui_interp = get_current_interp_info ();
 
-  return current_interpreter->procs->ui_out_proc (current_interpreter);
+  if (interp == NULL)
+    interp = ui_interp->current_interpreter;
+  return interp->procs->ui_out_proc (interp);
 }
 
 int
 current_interp_set_logging (int start_log, struct ui_file *out,
 			    struct ui_file *logfile)
 {
-  if (current_interpreter == NULL
-      || current_interpreter->procs->set_logging_proc == NULL)
+  struct ui_interp_info *ui_interp = get_current_interp_info ();
+  struct interp *interp = ui_interp->current_interpreter;
+
+  if (interp == NULL
+      || interp->procs->set_logging_proc == NULL)
     return 0;
 
-  return current_interpreter->procs->set_logging_proc (current_interpreter,
-						       start_log, out,
-						       logfile);
+  return interp->procs->set_logging_proc (interp, start_log, out, logfile);
 }
 
 /* Temporarily overrides the current interpreter.  */
 struct interp *
 interp_set_temp (const char *name)
 {
+  struct ui_interp_info *ui_interp = get_current_interp_info ();
   struct interp *interp = interp_lookup (name);
-  struct interp *old_interp = current_interpreter;
+  struct interp *old_interp = ui_interp->current_interpreter;
 
   if (interp)
-    current_interpreter = interp;
+    ui_interp->current_interpreter = interp;
   return old_interp;
 }
 
@@ -279,16 +299,15 @@ interp_name (struct interp *interp)
 int
 current_interp_named_p (const char *interp_name)
 {
-  if (current_interpreter)
-    return (strcmp (current_interpreter->name, interp_name) == 0);
+  struct ui_interp_info *ui_interp = get_current_interp_info ();
+  struct interp *interp = ui_interp->current_interpreter;
+
+  if (interp != NULL)
+    return (strcmp (interp->name, interp_name) == 0);
 
   return 0;
 }
 
-/* The interpreter that is active while `interp_exec' is active, NULL
-   at all other times.  */
-static struct interp *command_interpreter;
-
 /* The interpreter that was active when a command was executed.
    Normally that'd always be CURRENT_INTERPRETER, except that MI's
    -interpreter-exec command doesn't actually flip the current
@@ -302,28 +321,35 @@ static struct interp *command_interpreter;
 struct interp *
 command_interp (void)
 {
-  if (command_interpreter != NULL)
-    return command_interpreter;
+  struct ui_interp_info *ui_interp = get_current_interp_info ();
+
+  if (ui_interp->command_interpreter != NULL)
+    return ui_interp->command_interpreter;
   else
-    return current_interpreter;
+    return ui_interp->current_interpreter;
 }
 
 /* Run the current command interpreter's main loop.  */
 void
 current_interp_command_loop (void)
 {
-  gdb_assert (current_interpreter != NULL);
+  struct ui_interp_info *ui_interp = get_current_interp_info ();
+  struct interp *interp = ui_interp->current_interpreter;
+
+  gdb_assert (ui_interp->current_interpreter != NULL);
 
-  current_interpreter->procs->command_loop_proc (current_interpreter->data);
+  interp->procs->command_loop_proc (interp->data);
 }
 
 int
 interp_quiet_p (struct interp *interp)
 {
+  struct ui_interp_info *ui_interp = get_current_interp_info ();
+
   if (interp != NULL)
     return interp->quiet_p;
   else
-    return current_interpreter->quiet_p;
+    return ui_interp->current_interpreter->quiet_p;
 }
 
 static int
@@ -341,18 +367,20 @@ interp_set_quiet (struct interp *interp, int quiet)
 struct gdb_exception
 interp_exec (struct interp *interp, const char *command_str)
 {
+  struct ui_interp_info *ui_interp = get_current_interp_info ();
+
   struct gdb_exception ex;
   struct interp *save_command_interp;
 
   gdb_assert (interp->procs->exec_proc != NULL);
 
   /* See `command_interp' for why we do this.  */
-  save_command_interp = command_interpreter;
-  command_interpreter = interp;
+  save_command_interp = ui_interp->command_interpreter;
+  ui_interp->command_interpreter = interp;
 
   ex = interp->procs->exec_proc (interp->data, command_str);
 
-  command_interpreter = save_command_interp;
+  ui_interp->command_interpreter = save_command_interp;
 
   return ex;
 }
@@ -379,6 +407,7 @@ clear_interpreter_hooks (void)
 static void
 interpreter_exec_cmd (char *args, int from_tty)
 {
+  struct ui_interp_info *ui_interp = get_current_interp_info ();
   struct interp *old_interp, *interp_to_use;
   char **prules = NULL;
   char **trule = NULL;
@@ -400,7 +429,7 @@ interpreter_exec_cmd (char *args, int from_tty)
   if (nrules < 2)
     error (_("usage: interpreter-exec <interpreter> [ <command> ... ]"));
 
-  old_interp = current_interpreter;
+  old_interp = ui_interp->current_interpreter;
 
   interp_to_use = interp_lookup (prules[0]);
   if (interp_to_use == NULL)
@@ -438,12 +467,15 @@ static VEC (char_ptr) *
 interpreter_completer (struct cmd_list_element *ignore,
 		       const char *text, const char *word)
 {
+  struct ui_interp_info *ui_interp = get_current_interp_info ();
   int textlen;
   VEC (char_ptr) *matches = NULL;
   struct interp *interp;
 
   textlen = strlen (text);
-  for (interp = interp_list; interp != NULL; interp = interp->next)
+  for (interp = ui_interp->interp_list;
+       interp != NULL;
+       interp = interp->next)
     {
       if (strncmp (interp->name, text, textlen) == 0)
 	{
@@ -474,14 +506,19 @@ interpreter_completer (struct cmd_list_element *ignore,
 struct interp *
 top_level_interpreter (void)
 {
-  return top_level_interpreter_ptr;  
+  struct ui_interp_info *ui_interp = get_current_interp_info ();
+
+  return ui_interp->top_level_interpreter_ptr;
 }
 
 void *
 top_level_interpreter_data (void)
 {
-  gdb_assert (top_level_interpreter_ptr);
-  return top_level_interpreter_ptr->data;  
+  struct interp *interp;
+
+  interp = top_level_interpreter ();
+  gdb_assert (interp != NULL);
+  return interp->data;
 }
 
 /* This just adds the "interpreter-exec" command.  */
diff --git a/gdb/interps.h b/gdb/interps.h
index 19cd1c2..f0badc5 100644
--- a/gdb/interps.h
+++ b/gdb/interps.h
@@ -93,15 +93,6 @@ extern struct interp *top_level_interpreter (void);
 
 extern struct interp *command_interp (void);
 
-/* True if the current interpreter is in async mode, false if in sync
-   mode.  If in sync mode, running a synchronous execution command
-   (with execute_command, e.g, "next") will not return until the
-   command is finished.  If in async mode, then running a synchronous
-   command returns right after resuming the target.  Waiting for the
-   command's completion is later done on the top event loop (using
-   continuations).  */
-extern int interpreter_async;
-
 extern void clear_interpreter_hooks (void);
 
 /* well-known interpreters */
diff --git a/gdb/main.c b/gdb/main.c
index 44d1a90..72d0369 100644
--- a/gdb/main.c
+++ b/gdb/main.c
@@ -309,7 +309,7 @@ captured_command_loop (void *data)
 {
   /* Top-level execution commands can be run in the background from
      here on.  */
-  interpreter_async = 1;
+  current_ui->async = 1;
 
   current_interp_command_loop ();
   /* FIXME: cagney/1999-11-05: A correct command_loop() implementaton
diff --git a/gdb/python/python.c b/gdb/python/python.c
index 7202105..a164e37 100644
--- a/gdb/python/python.c
+++ b/gdb/python/python.c
@@ -331,8 +331,8 @@ python_interactive_command (char *arg, int from_tty)
   struct cleanup *cleanup;
   int err;
 
-  cleanup = make_cleanup_restore_integer (&interpreter_async);
-  interpreter_async = 0;
+  cleanup = make_cleanup_restore_integer (&current_ui->async);
+  current_ui->async = 0;
 
   arg = skip_spaces (arg);
 
@@ -476,8 +476,8 @@ python_command (char *arg, int from_tty)
 
   cleanup = ensure_python_env (get_current_arch (), current_language);
 
-  make_cleanup_restore_integer (&interpreter_async);
-  interpreter_async = 0;
+  make_cleanup_restore_integer (&current_ui->async);
+  current_ui->async = 0;
 
   arg = skip_spaces (arg);
   if (arg && *arg)
@@ -659,8 +659,8 @@ execute_gdb_command (PyObject *self, PyObject *args, PyObject *kw)
       char *copy = xstrdup (arg);
       struct cleanup *cleanup = make_cleanup (xfree, copy);
 
-      make_cleanup_restore_integer (&interpreter_async);
-      interpreter_async = 0;
+      make_cleanup_restore_integer (&current_ui->async);
+      current_ui->async = 0;
 
       prevent_dont_repeat ();
       if (to_string)
diff --git a/gdb/top.c b/gdb/top.c
index 26aee8a..3ecaaeb 100644
--- a/gdb/top.c
+++ b/gdb/top.c
@@ -392,7 +392,7 @@ maybe_wait_sync_command_done (int was_sync)
      command's list, running command hooks or similars), and we
      just ran a synchronous command that started the target, wait
      for that command to end.  */
-  if (!interpreter_async && !was_sync && sync_execution)
+  if (!current_ui->async && !was_sync && sync_execution)
     wait_sync_command_done ();
 }
 
@@ -510,8 +510,8 @@ execute_command_to_string (char *p, int from_tty)
      restoration callbacks.  */
   cleanup = set_batch_flag_and_make_cleanup_restore_page_info ();
 
-  make_cleanup_restore_integer (&interpreter_async);
-  interpreter_async = 0;
+  make_cleanup_restore_integer (&current_ui->async);
+  current_ui->async = 0;
 
   str_file = mem_fileopen ();
 
diff --git a/gdb/top.h b/gdb/top.h
index 8beaa4a..2daa03b 100644
--- a/gdb/top.h
+++ b/gdb/top.h
@@ -23,6 +23,8 @@
 #include "buffer.h"
 #include "event-loop.h"
 
+struct tl_interp_info;
+
 /* All about a user interface instance.  Each user interface has its
    own I/O files/streams, readline state, its own top level
    interpreter (for the main UI, this is the interpreter specified
@@ -50,6 +52,19 @@ struct ui
      processing.  */
   void (*input_handler) (char *);
 
+  /* Each UI has its own independent set of interpreters.  */
+  struct ui_interp_info *interp_info;
+
+  /* True if the UI is in async mode, false if in sync mode.  If in
+     sync mode, a synchronous execution command (e.g, "next") does not
+     return until the command is finished.  If in async mode, then
+     running a synchronous command returns right after resuming the
+     target.  Waiting for the command's completion is later done on
+     the top event loop.  For the main UI, this starts out disabled,
+     until all the explicit command line arguments (e.g., `gdb -ex
+     "start" -ex "next"') are processed.  */
+  int async;
+
   /* The fields below that start with "m_" are "private".  They're
      meant to be accessed through wrapper macros that make them look
      like globals.  */
