keyboard.c, keymap.c: Use bool for booleans.

* dispnew.c (sit_for): Distinguish between 3-way display_option
and boolean do_display.
* keyboard.c (single_kboard, this_command_key_count_reset)
(waiting_for_input, echoing, immediate_quit, input_pending)
(interrupt_input, interrupts_deferred, pop_kboard)
(temporarily_switch_to_single_kboard, ignore_mouse_drag_p)
(command_loop_1, adjust_point_for_property)
(safe_run_hooks_error, input_polling_used, read_char):
(help_char_p, readable_events, kbd_buffer_events_waiting)
(kbd_buffer_get_event, timer_check_2, make_lispy_event)
(lucid_event_type_list_p, get_input_pending):
(gobble_input, menu_separator_name_p, menu_bar_item)
(parse_menu_item, parse_tool_bar_item, read_char_x_menu_prompt)
(read_char_minibuf_menu_prompt, access_keymap_keyremap)
(keyremap_step, test_undefined, read_key_sequence)
(detect_input_pending, detect_input_pending_ignore_squeezables)
(detect_input_pending_run_timers, requeued_events_pending_p)
(quit_throw_to_read_char, Fset_input_interrupt_mode):
* keymap.c (get_keymap, keymap_parent, keymap_memberp)
(access_keymap_1, access_keymap, map_keymap, get_keyelt)
(Fdefine_key, Flookup_key, struct accessible_keymaps_data)
(accessible_keymaps_1, Fkey_description, push_key_description):
(shadow_lookup, struct where_is_internal_data)
(where_is_internal, Fwhere_is_internal, where_is_internal_1)
(Fdescribe_buffer_bindings, describe_map_tree, struct describe_map_elt)
(describe_map, describe_vector):
* menu.c (single_menu_item):
* nsmenu.m (ns_update_menubar):
* process.c (wait_reading_process_output):
* search.c (scan_buffer, scan_newline):
Use bool for boolean.
* keyboard.c (timers_run, swallow_events)
(detect_input_pending_run_timers):
* process.c (wait_reading_process_output):
Use unsigned for counter where wraparound-on-overflow is desired,
since unsigned is guaranteed to have that behavior and signed is not.
(read_char): Use ptrdiff_t for string length.
(get_input_pending): Remove first argument, since it was always
the same pointer-to-int (now pointer-to-boolean) &input_pending,
and behave as if it had that value.  Return new value of
input_pending.  All callers changed.
* keyboard.h (struct kboard): Use unsigned : 1 for boolean member
immediate_echo.  Use ptrdiff_t for echo_after_prompt, since it's
a string length.
* keymap.c (push_key_description): Omit last arg, which was always 1.
All callers changed.

12 files changed, 319 insertions, 305 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index a05c426a452..daa370105ee 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,5 +1,53 @@
 2012-10-10  Paul Eggert  <eggert@cs.ucla.edu>
 
+        keyboard.c, keymap.c: Use bool for booleans.
+        * dispnew.c (sit_for): Distinguish between 3-way display_option
+        and boolean do_display.
+        * keyboard.c (single_kboard, this_command_key_count_reset)
+        (waiting_for_input, echoing, immediate_quit, input_pending)
+        (interrupt_input, interrupts_deferred, pop_kboard)
+        (temporarily_switch_to_single_kboard, ignore_mouse_drag_p)
+        (command_loop_1, adjust_point_for_property)
+        (safe_run_hooks_error, input_polling_used, read_char):
+        (help_char_p, readable_events, kbd_buffer_events_waiting)
+        (kbd_buffer_get_event, timer_check_2, make_lispy_event)
+        (lucid_event_type_list_p, get_input_pending):
+        (gobble_input, menu_separator_name_p, menu_bar_item)
+        (parse_menu_item, parse_tool_bar_item, read_char_x_menu_prompt)
+        (read_char_minibuf_menu_prompt, access_keymap_keyremap)
+        (keyremap_step, test_undefined, read_key_sequence)
+        (detect_input_pending, detect_input_pending_ignore_squeezables)
+        (detect_input_pending_run_timers, requeued_events_pending_p)
+        (quit_throw_to_read_char, Fset_input_interrupt_mode):
+        * keymap.c (get_keymap, keymap_parent, keymap_memberp)
+        (access_keymap_1, access_keymap, map_keymap, get_keyelt)
+        (Fdefine_key, Flookup_key, struct accessible_keymaps_data)
+        (accessible_keymaps_1, Fkey_description, push_key_description):
+        (shadow_lookup, struct where_is_internal_data)
+        (where_is_internal, Fwhere_is_internal, where_is_internal_1)
+        (Fdescribe_buffer_bindings, describe_map_tree, struct describe_map_elt)
+        (describe_map, describe_vector):
+        * menu.c (single_menu_item):
+        * nsmenu.m (ns_update_menubar):
+        * process.c (wait_reading_process_output):
+        * search.c (scan_buffer, scan_newline):
+        Use bool for boolean.
+        * keyboard.c (timers_run, swallow_events)
+        (detect_input_pending_run_timers):
+        * process.c (wait_reading_process_output):
+        Use unsigned for counter where wraparound-on-overflow is desired,
+        since unsigned is guaranteed to have that behavior and signed is not.
+        (read_char): Use ptrdiff_t for string length.
+        (get_input_pending): Remove first argument, since it was always
+        the same pointer-to-int (now pointer-to-boolean) &input_pending,
+        and behave as if it had that value.  Return new value of
+        input_pending.  All callers changed.
+        * keyboard.h (struct kboard): Use unsigned : 1 for boolean member
+        immediate_echo.  Use ptrdiff_t for echo_after_prompt, since it's
+        a string length.
+        * keymap.c (push_key_description): Omit last arg, which was always 1.
+        All callers changed.
+
         * regex.c (immediate_quit) [emacs]: Remove duplicate decl.
 
 2012-10-10  Juanma Barranquero  <lekktu@gmail.com>
diff --git a/src/dispnew.c b/src/dispnew.c
index fd4985452ae..0956e3f2905 100644
--- a/src/dispnew.c
+++ b/src/dispnew.c
@@ -5918,15 +5918,16 @@ additional wait period, in milliseconds; this is for backwards compatibility.
    TIMEOUT is number of seconds to wait (float or integer),
    or t to wait forever.
    READING is true if reading input.
-   If DO_DISPLAY is >0 display process output while waiting.
-   If DO_DISPLAY is >1 perform an initial redisplay before waiting.
+   If DISPLAY_OPTION is >0 display process output while waiting.
+   If DISPLAY_OPTION is >1 perform an initial redisplay before waiting.
 */
 
 Lisp_Object
-sit_for (Lisp_Object timeout, bool reading, int do_display)
+sit_for (Lisp_Object timeout, bool reading, int display_option)
 {
   intmax_t sec;
   int nsec;
+  bool do_display = display_option > 0;
 
   swallow_events (do_display);
 
@@ -5934,7 +5935,7 @@ sit_for (Lisp_Object timeout, bool reading, int do_display)
       || !NILP (Vexecuting_kbd_macro))
     return Qnil;
 
-  if (do_display >= 2)
+  if (display_option > 1)
     redisplay_preserve_echo_area (2);
 
   if (INTEGERP (timeout))
diff --git a/src/keyboard.c b/src/keyboard.c
index 61481c5f0f6..d58178b7561 100644
--- a/src/keyboard.c
+++ b/src/keyboard.c
@@ -86,8 +86,8 @@ KBOARD *initial_kboard;
 KBOARD *current_kboard;
 KBOARD *all_kboards;
 
-/* Nonzero in the single-kboard state, 0 in the any-kboard state.  */
-static int single_kboard;
+/* True in the single-kboard state, false in the any-kboard state.  */
+static bool single_kboard;
 
 /* Non-nil disable property on a command means
    do not execute it; call disabled-command-function's value instead.  */
@@ -113,9 +113,9 @@ static Lisp_Object recent_keys;
 Lisp_Object this_command_keys;
 ptrdiff_t this_command_key_count;
 
-/* 1 after calling Freset_this_command_lengths.
-   Usually it is 0.  */
-static int this_command_key_count_reset;
+/* True after calling Freset_this_command_lengths.
+   Usually it is false.  */
+static bool this_command_key_count_reset;
 
 /* This vector is used as a buffer to record the events that were actually read
    by read_key_sequence.  */
@@ -140,11 +140,11 @@ static ptrdiff_t before_command_echo_length;
 static sys_jmp_buf getcjmp;
 
 /* True while doing kbd input.  */
-int waiting_for_input;
+bool waiting_for_input;
 
 /* True while displaying for echoing.   Delays C-g throwing.  */
 
-static int echoing;
+static bool echoing;
 
 /* Non-null means we can start echoing at the next input pause even
    though there is something in the echo area.  */
@@ -163,8 +163,8 @@ struct kboard *echo_kboard;
 
 Lisp_Object echo_message_buffer;
 
-/* Nonzero means C-g should cause immediate error-signal.  */
-int immediate_quit;
+/* True means C-g should cause immediate error-signal.  */
+bool immediate_quit;
 
 /* Character that causes a quit.  Normally C-g.
 
@@ -270,7 +270,7 @@ static Lisp_Object Qhelp_form_show;
 static FILE *dribble;
 
 /* Nonzero if input is available.  */
-int input_pending;
+bool input_pending;
 
 /* Circular buffer for pre-read keyboard input.  */
 
@@ -372,18 +372,18 @@ static ptrdiff_t echo_length (void);
 static Lisp_Object Qpolling_period;
 
 /* Incremented whenever a timer is run.  */
-int timers_run;
+unsigned timers_run;
 
 /* Address (if not 0) of EMACS_TIME to zero out if a SIGIO interrupt
    happens.  */
 EMACS_TIME *input_available_clear_time;
 
-/* Nonzero means use SIGIO interrupts; zero means use CBREAK mode.
-   Default is 1 if INTERRUPT_INPUT is defined.  */
-int interrupt_input;
+/* True means use SIGIO interrupts; false means use CBREAK mode.
+   Default is true if INTERRUPT_INPUT is defined.  */
+bool interrupt_input;
 
 /* Nonzero while interrupts are temporarily deferred during redisplay.  */
-int interrupts_deferred;
+bool interrupts_deferred;
 
 /* If we support a window system, turn on the code to poll periodically
    to detect C-g.  It isn't actually used when doing interrupt input.  */
@@ -411,10 +411,10 @@ static EMACS_TIME timer_last_idleness_start_time;
 /* Function for init_keyboard to call with no args (if nonzero).  */
 static void (*keyboard_init_hook) (void);
 
-static void get_input_pending (int *, int);
-static int readable_events (int);
+static bool get_input_pending (int);
+static bool readable_events (int);
 static Lisp_Object read_char_x_menu_prompt (ptrdiff_t, Lisp_Object *,
-                                            Lisp_Object, int *);
+                                            Lisp_Object, bool *);
 static Lisp_Object read_char_minibuf_menu_prompt (int, ptrdiff_t,
                                                   Lisp_Object *);
 static Lisp_Object make_lispy_event (struct input_event *);
@@ -428,7 +428,7 @@ static Lisp_Object modify_event_symbol (ptrdiff_t, int, Lisp_Object,
                                         Lisp_Object, const char *const *,
                                         Lisp_Object *, ptrdiff_t);
 static Lisp_Object make_lispy_switch_frame (Lisp_Object);
-static int help_char_p (Lisp_Object);
+static bool help_char_p (Lisp_Object);
 static void save_getcjmp (sys_jmp_buf);
 static void restore_getcjmp (sys_jmp_buf);
 static Lisp_Object apply_modifiers (int, Lisp_Object);
@@ -438,7 +438,7 @@ static Lisp_Object restore_kboard_configuration (Lisp_Object);
 static void deliver_input_available_signal (int signo);
 #endif
 static void handle_interrupt (bool);
-static _Noreturn void quit_throw_to_read_char (int);
+static _Noreturn void quit_throw_to_read_char (bool);
 static void process_special_events (void);
 static void timer_start_idle (void);
 static void timer_stop_idle (void);
@@ -516,7 +516,7 @@ echo_char (Lisp_Object c)
 
       if (INTEGERP (c))
         {
-          ptr = push_key_description (XINT (c), ptr, 1);
+          ptr = push_key_description (XINT (c), ptr);
         }
       else if (SYMBOLP (c))
         {
@@ -925,7 +925,7 @@ pop_kboard (void)
 {
   struct terminal *t;
   struct kboard_stack *p = kboard_stack;
-  int found = 0;
+  bool found = 0;
   for (t = terminal_list; t; t = t->next_terminal)
     {
       if (t->kboard == p->kboard)
@@ -958,7 +958,7 @@ pop_kboard (void)
 void
 temporarily_switch_to_single_kboard (struct frame *f)
 {
-  int was_locked = single_kboard;
+  bool was_locked = single_kboard;
   if (was_locked)
     {
       if (f != NULL && FRAME_KBOARD (f) != current_kboard)
@@ -1057,12 +1057,7 @@ cmd_error (Lisp_Object data)
   Vprint_length = old_length;
 
   Vquit_flag = Qnil;
-
   Vinhibit_quit = Qnil;
-#if 0 /* This shouldn't be necessary anymore.  --lorentey  */
-  if (command_loop_level == 0 && minibuf_level == 0)
-    any_kboard_state ();
-#endif
 
   return make_number (0);
 }
@@ -1149,12 +1144,6 @@ command_loop (void)
     while (1)
       {
         internal_catch (Qtop_level, top_level_1, Qnil);
-#if 0 /* This shouldn't be necessary anymore.  --lorentey  */
-        /* Reset single_kboard in case top-level set it while
-           evaluating an -f option, or we are stuck there for some
-           other reason.  */
-        any_kboard_state ();
-#endif
         internal_catch (Qtop_level, command_loop_2, Qnil);
         executing_kbd_macro = Qnil;
 
@@ -1265,8 +1254,7 @@ tracking_off (Lisp_Object old_value)
       if (!readable_events (READABLE_EVENTS_DO_TIMERS_NOW))
         {
           redisplay_preserve_echo_area (6);
-          get_input_pending (&input_pending,
-                             READABLE_EVENTS_DO_TIMERS_NOW);
+          get_input_pending (READABLE_EVENTS_DO_TIMERS_NOW);
         }
     }
   return Qnil;
@@ -1301,7 +1289,7 @@ usage: (track-mouse BODY...)  */)
 #if !defined HAVE_WINDOW_SYSTEM || defined USE_GTK || defined HAVE_NS
 static
 #endif
-int ignore_mouse_drag_p;
+bool ignore_mouse_drag_p;
 
 static FRAME_PTR
 some_mouse_moved (void)
@@ -1329,9 +1317,9 @@ some_mouse_moved (void)
    sans error-handling encapsulation.  */
 
 static int read_key_sequence (Lisp_Object *, int, Lisp_Object,
-                              int, int, int);
+                              bool, bool, bool);
 void safe_run_hooks (Lisp_Object);
-static void adjust_point_for_property (ptrdiff_t, int);
+static void adjust_point_for_property (ptrdiff_t, bool);
 
 /* Cancel hourglass from protect_unwind.
    ARG is not used.  */
@@ -1359,10 +1347,7 @@ command_loop_1 (void)
   int i;
   EMACS_INT prev_modiff = 0;
   struct buffer *prev_buffer = NULL;
-#if 0 /* This shouldn't be necessary anymore.  --lorentey  */
-  int was_locked = single_kboard;
-#endif
-  int already_adjusted = 0;
+  bool already_adjusted = 0;
 
   kset_prefix_arg (current_kboard, Qnil);
   kset_last_prefix_arg (current_kboard, Qnil);
@@ -1731,10 +1716,6 @@ command_loop_1 (void)
       if (!NILP (KVAR (current_kboard, defining_kbd_macro))
           && NILP (KVAR (current_kboard, Vprefix_arg)))
         finalize_kbd_macro_chars ();
-#if 0 /* This shouldn't be necessary anymore.  --lorentey  */
-      if (!was_locked)
-        any_kboard_state ();
-#endif
     }
 }
 
@@ -1744,7 +1725,7 @@ command_loop_1 (void)
    LAST_PT is the last position of point.  */
 
 static void
-adjust_point_for_property (ptrdiff_t last_pt, int modified)
+adjust_point_for_property (ptrdiff_t last_pt, bool modified)
 {
   ptrdiff_t beg, end;
   Lisp_Object val, overlay, tmp;
@@ -1752,7 +1733,7 @@ adjust_point_for_property (ptrdiff_t last_pt, int modified)
      suppress the point adjustment for automatic composition so that a
      user can keep inserting another character at point or keep
      deleting characters around point.  */
-  int check_composition = ! modified, check_display = 1, check_invisible = 1;
+  bool check_composition = ! modified, check_display = 1, check_invisible = 1;
   ptrdiff_t orig_pt = PT;
 
   /* FIXME: cycling is probably not necessary because these properties
@@ -1791,7 +1772,8 @@ adjust_point_for_property (ptrdiff_t last_pt, int modified)
       check_display = 0;
       if (check_invisible && PT > BEGV && PT < ZV)
         {
-          int inv, ellipsis = 0;
+          int inv;
+          bool ellipsis = 0;
           beg = end = PT;
 
           /* Find boundaries `beg' and `end' of the invisible area, if any.  */
@@ -1920,7 +1902,7 @@ safe_run_hooks_error (Lisp_Object error_data)
   if (SYMBOLP (hook))
     {
       Lisp_Object val;
-      int found = 0;
+      bool found = 0;
       Lisp_Object newval = Qnil;
       for (val = find_symbol_value (hook); CONSP (val); val = XCDR (val))
         if (EQ (fun, XCAR (val)))
@@ -2050,9 +2032,9 @@ start_polling (void)
 #endif
 }
 
-/* Nonzero if we are using polling to handle input asynchronously.  */
+/* True if we are using polling to handle input asynchronously.  */
 
-int
+bool
 input_polling_used (void)
 {
 #ifdef POLL_FOR_INPUT
@@ -2228,7 +2210,7 @@ show_help_echo (Lisp_Object help, Lisp_Object window, Lisp_Object object,
 
 /* Input of single characters from keyboard */
 
-static Lisp_Object kbd_buffer_get_event (KBOARD **kbp, int *used_mouse_menu,
+static Lisp_Object kbd_buffer_get_event (KBOARD **kbp, bool *used_mouse_menu,
                                          EMACS_TIME *end_time);
 static void record_char (Lisp_Object c);
 
@@ -2265,9 +2247,9 @@ do { if (polling_stopped_here) start_polling ();	\
    not to run input methods, but in other respects to act as if
    not reading a key sequence.
 
-   If USED_MOUSE_MENU is non-null, then we set *USED_MOUSE_MENU to 1
-   if we used a mouse menu to read the input, or zero otherwise.  If
-   USED_MOUSE_MENU is null, we don't dereference it.
+   If USED_MOUSE_MENU is non-null, then set *USED_MOUSE_MENU to true
+   if we used a mouse menu to read the input, or false otherwise.  If
+   USED_MOUSE_MENU is null, don't dereference it.
 
    Value is -2 when we find input on another keyboard.  A second call
    to read_char will read it.
@@ -2281,7 +2263,7 @@ do { if (polling_stopped_here) start_polling ();	\
 Lisp_Object
 read_char (int commandflag, ptrdiff_t nmaps, Lisp_Object *maps,
            Lisp_Object prev_event,
-           int *used_mouse_menu, EMACS_TIME *end_time)
+           bool *used_mouse_menu, EMACS_TIME *end_time)
 {
   Lisp_Object c;
   ptrdiff_t jmpcount;
@@ -2290,9 +2272,9 @@ read_char (int commandflag, ptrdiff_t nmaps, Lisp_Object *maps,
   Lisp_Object tem, save;
   volatile Lisp_Object previous_echo_area_message;
   volatile Lisp_Object also_record;
-  volatile int reread;
+  volatile bool reread;
   struct gcpro gcpro1, gcpro2;
-  int volatile polling_stopped_here = 0;
+  bool volatile polling_stopped_here = 0;
   struct kboard *orig_kboard = current_kboard;
 
   also_record = Qnil;
@@ -2328,7 +2310,7 @@ read_char (int commandflag, ptrdiff_t nmaps, Lisp_Object *maps,
 
   if (CONSP (Vunread_command_events))
     {
-      int was_disabled = 0;
+      bool was_disabled = 0;
 
       c = XCAR (Vunread_command_events);
       Vunread_command_events = XCDR (Vunread_command_events);
@@ -2430,7 +2412,7 @@ read_char (int commandflag, ptrdiff_t nmaps, Lisp_Object *maps,
   /* if redisplay was requested */
   if (commandflag >= 0)
     {
-      int echo_current = EQ (echo_message_buffer, echo_area_buffer[0]);
+      bool echo_current = EQ (echo_message_buffer, echo_area_buffer[0]);
 
         /* If there is pending input, process any events which are not
            user-visible, such as X selection_request events.  */
@@ -2862,12 +2844,6 @@ read_char (int commandflag, ptrdiff_t nmaps, Lisp_Object *maps,
   if (!NILP (tem))
     {
       struct buffer *prev_buffer = current_buffer;
-#if 0 /* This shouldn't be necessary anymore. --lorentey  */
-      int was_locked = single_kboard;
-      ptrdiff_t count = SPECPDL_INDEX ();
-      record_single_kboard_state ();
-#endif
-
       last_input_event = c;
       Fcommand_execute (tem, Qnil, Fvector (1, &last_input_event), Qt);
 
@@ -2878,13 +2854,6 @@ read_char (int commandflag, ptrdiff_t nmaps, Lisp_Object *maps,
            example banishing the mouse under mouse-avoidance-mode.  */
         timer_resume_idle ();
 
-#if 0 /* This shouldn't be necessary anymore. --lorentey  */
-      /* Resume allowing input from any kboard, if that was true before.  */
-      if (!was_locked)
-        any_kboard_state ();
-      unbind_to (count, Qnil);
-#endif
-
       if (current_buffer != prev_buffer)
         {
           /* The command may have changed the keymaps.  Pretend there
@@ -2992,15 +2961,15 @@ read_char (int commandflag, ptrdiff_t nmaps, Lisp_Object *maps,
     {
       Lisp_Object keys;
       ptrdiff_t key_count;
-      int key_count_reset;
+      bool key_count_reset;
       struct gcpro gcpro1;
       ptrdiff_t count = SPECPDL_INDEX ();
 
       /* Save the echo status.  */
-      int saved_immediate_echo = current_kboard->immediate_echo;
+      bool saved_immediate_echo = current_kboard->immediate_echo;
       struct kboard *saved_ok_to_echo = ok_to_echo_at_next_pause;
       Lisp_Object saved_echo_string = KVAR (current_kboard, echo_string);
-      int saved_echo_after_prompt = current_kboard->echo_after_prompt;
+      ptrdiff_t saved_echo_after_prompt = current_kboard->echo_after_prompt;
 
 #if 0
       if (before_command_restore_flag)
@@ -3201,9 +3170,9 @@ record_menu_key (Lisp_Object c)
   num_input_events++;
 }
 
-/* Return 1 if should recognize C as "the help character".  */
+/* Return true if should recognize C as "the help character".  */
 
-static int
+static bool
 help_char_p (Lisp_Object c)
 {
   Lisp_Object tail;
@@ -3375,7 +3344,7 @@ restore_getcjmp (sys_jmp_buf temp)
 
 /* Return true if there are any events in the queue that read-char
    would return.  If this returns false, a read-char would block.  */
-static int
+static bool
 readable_events (int flags)
 {
   if (flags & READABLE_EVENTS_DO_TIMERS_NOW)
@@ -3714,15 +3683,14 @@ discard_mouse_events (void)
 }
 
 
-/* Return non-zero if there are any real events waiting in the event
+/* Return true if there are any real events waiting in the event
    buffer, not counting `NO_EVENT's.
 
-   If DISCARD is non-zero, discard NO_EVENT events at the front of
-   the input queue, possibly leaving the input queue empty if there
-   are no real input events.  */
+   Discard NO_EVENT events at the front of the input queue, possibly
+   leaving the input queue empty if there are no real input events.  */
 
-int
-kbd_buffer_events_waiting (int discard)
+bool
+kbd_buffer_events_waiting (void)
 {
   struct input_event *sp;
 
@@ -3734,9 +3702,7 @@ kbd_buffer_events_waiting (int discard)
         sp = kbd_buffer;
     }
 
-  if (discard)
-    kbd_fetch_ptr = sp;
-
+  kbd_fetch_ptr = sp;
   return sp != kbd_store_ptr && sp->kind != NO_EVENT;
 }
 
@@ -3758,7 +3724,7 @@ clear_event (struct input_event *event)
 
 static Lisp_Object
 kbd_buffer_get_event (KBOARD **kbp,
-                      int *used_mouse_menu,
+                      bool *used_mouse_menu,
                       EMACS_TIME *end_time)
 {
   Lisp_Object obj;
@@ -4203,14 +4169,14 @@ process_special_events (void)
    are ripe, and return, without reading any user-visible events.  */
 
 void
-swallow_events (int do_display)
+swallow_events (bool do_display)
 {
-  int old_timers_run;
+  unsigned old_timers_run;
 
   process_special_events ();
 
   old_timers_run = timers_run;
-  get_input_pending (&input_pending, READABLE_EVENTS_DO_TIMERS_NOW);
+  get_input_pending (READABLE_EVENTS_DO_TIMERS_NOW);
 
   if (timers_run != old_timers_run && do_display)
     redisplay_preserve_echo_area (7);
@@ -4337,7 +4303,7 @@ timer_check_2 (Lisp_Object timers, Lisp_Object idle_timers)
       EMACS_TIME difference;
       EMACS_TIME timer_difference = invalid_emacs_time ();
       EMACS_TIME idle_timer_difference = invalid_emacs_time ();
-      int ripe, timer_ripe = 0, idle_timer_ripe = 0;
+      bool ripe, timer_ripe = 0, idle_timer_ripe = 0;
 
       /* Set TIMER and TIMER_DIFFERENCE
          based on the next ordinary timer.
@@ -5441,7 +5407,7 @@ make_lispy_event (struct input_event *event)
 #endif
       {
         int button = event->code;
-        int is_double;
+        bool is_double;
         Lisp_Object position;
         Lisp_Object *start_pos_ptr;
         Lisp_Object start_pos;
@@ -5722,7 +5688,7 @@ make_lispy_event (struct input_event *event)
           struct frame *fr;
           int fuzz;
           int symbol_num;
-          int is_double;
+          bool is_double;
 
           if (WINDOWP (event->frame_or_window))
             fr = XFRAME (XWINDOW (event->frame_or_window)->frame);
@@ -6664,11 +6630,11 @@ parse_solitary_modifier (Lisp_Object symbol)
   return 0;
 }
 
-/* Return 1 if EVENT is a list whose elements are all integers or symbols.
+/* Return true if EVENT is a list whose elements are all integers or symbols.
    Such a list is not valid as an event,
    but it can be a Lucid-style event type list.  */
 
-int
+bool
 lucid_event_type_list_p (Lisp_Object object)
 {
   Lisp_Object tail;
@@ -6693,8 +6659,10 @@ lucid_event_type_list_p (Lisp_Object object)
   return NILP (tail);
 }
 
-/* Store into *addr a value nonzero if terminal input chars are available.
-   Serves the purpose of ioctl (0, FIONREAD, addr)
+/* Return true if terminal input chars are available.
+   Also, store the return value into INPUT_PENDING.
+
+   Serves the purpose of ioctl (0, FIONREAD, ...)
    but works even if FIONREAD does not exist.
    (In fact, this may actually read some input.)
 
@@ -6705,19 +6673,21 @@ lucid_event_type_list_p (Lisp_Object object)
    If READABLE_EVENTS_IGNORE_SQUEEZABLES is set in FLAGS, ignore mouse
    movements and toolkit scroll bar thumb drags.  */
 
-static void
-get_input_pending (int *addr, int flags)
+static bool
+get_input_pending (int flags)
 {
   /* First of all, have we already counted some input?  */
-  *addr = (!NILP (Vquit_flag) || readable_events (flags));
+  input_pending = (!NILP (Vquit_flag) || readable_events (flags));
 
   /* If input is being read as it arrives, and we have none, there is none.  */
-  if (*addr > 0 || (interrupt_input && ! interrupts_deferred))
-    return;
+  if (!input_pending && (!interrupt_input || interrupts_deferred))
+    {
+      /* Try to read some input and see how much we get.  */
+      gobble_input ();
+      input_pending = (!NILP (Vquit_flag) || readable_events (flags));
+    }
 
-  /* Try to read some input and see how much we get.  */
-  gobble_input ();
-  *addr = (!NILP (Vquit_flag) || readable_events (flags));
+  return input_pending;
 }
 
 /* Put a BUFFER_SWITCH_EVENT in the buffer
@@ -6767,7 +6737,7 @@ int
 gobble_input (void)
 {
   int nread = 0;
-  int err = 0;
+  bool err = 0;
   struct terminal *t;
 
   /* Store pending user signal events, if any.  */
@@ -7337,9 +7307,9 @@ static const char* separator_names[] = {
   0,
 };
 
-/* Return non-zero if LABEL specifies a separator.  */
+/* Return true if LABEL specifies a separator.  */
 
-int
+bool
 menu_separator_name_p (const char *label)
 {
   if (!label)
@@ -7514,6 +7484,7 @@ menu_bar_item (Lisp_Object key, Lisp_Object item, Lisp_Object dummy1, void *dumm
 {
   struct gcpro gcpro1;
   int i;
+  bool parsed;
   Lisp_Object tem;
 
   if (EQ (item, Qundefined))
@@ -7545,9 +7516,9 @@ menu_bar_item (Lisp_Object key, Lisp_Object item, Lisp_Object dummy1, void *dumm
      parse_menu_item, so that if it turns out it wasn't a menu item,
      it still correctly hides any further menu item.  */
   GCPRO1 (key);
-  i = parse_menu_item (item, 1);
+  parsed = parse_menu_item (item, 1);
   UNGCPRO;
-  if (!i)
+  if (!parsed)
     return;
 
   item = AREF (item_properties, ITEM_PROPERTY_DEF);
@@ -7623,7 +7594,7 @@ menu_item_eval_property (Lisp_Object sexpr)
    parse_menu_item returns true if the item is a menu item and false
    otherwise.  */
 
-int
+bool
 parse_menu_item (Lisp_Object item, int inmenubar)
 {
   Lisp_Object def, tem, item_string, start;
@@ -7923,7 +7894,7 @@ static Lisp_Object QCrtl;
 
 static void init_tool_bar_items (Lisp_Object);
 static void process_tool_bar_item (Lisp_Object, Lisp_Object, Lisp_Object, void*);
-static int parse_tool_bar_item (Lisp_Object, Lisp_Object);
+static bool parse_tool_bar_item (Lisp_Object, Lisp_Object);
 static void append_tool_bar_item (void);
 
 
@@ -8056,7 +8027,7 @@ set_prop (ptrdiff_t idx, Lisp_Object val)
 
 
 /* Parse a tool bar item specification ITEM for key KEY and return the
-   result in tool_bar_item_properties.  Value is zero if ITEM is
+   result in tool_bar_item_properties.  Value is false if ITEM is
    invalid.
 
    ITEM is a list `(menu-item CAPTION BINDING PROPS...)'.
@@ -8101,12 +8072,13 @@ set_prop (ptrdiff_t idx, Lisp_Object val)
 
    A text label to show with the tool bar button if labels are enabled.  */
 
-static int
+static bool
 parse_tool_bar_item (Lisp_Object key, Lisp_Object item)
 {
   Lisp_Object filter = Qnil;
   Lisp_Object caption;
-  int i, have_label = 0;
+  int i;
+  bool have_label = 0;
 
   /* Definition looks like `(menu-item CAPTION BINDING PROPS...)'.
      Rule out items that aren't lists, don't start with
@@ -8363,9 +8335,9 @@ append_tool_bar_item (void)
    PREV_EVENT is the previous input event, or nil if we are reading
    the first event of a key sequence.
 
-   If USED_MOUSE_MENU is non-null, then we set *USED_MOUSE_MENU to 1
-   if we used a mouse menu to read the input, or zero otherwise.  If
-   USED_MOUSE_MENU is null, we don't dereference it.
+   If USED_MOUSE_MENU is non-null, set *USED_MOUSE_MENU to true
+   if we used a mouse menu to read the input, or false otherwise.  If
+   USED_MOUSE_MENU is null, don't dereference it.
 
    The prompting is done based on the prompt-string of the map
    and the strings associated with various map elements.
@@ -8378,7 +8350,7 @@ append_tool_bar_item (void)
 
 static Lisp_Object
 read_char_x_menu_prompt (ptrdiff_t nmaps, Lisp_Object *maps,
-                         Lisp_Object prev_event, int *used_mouse_menu)
+                         Lisp_Object prev_event, bool *used_mouse_menu)
 {
 #ifdef HAVE_MENUS
   ptrdiff_t mapno;
@@ -8472,7 +8444,7 @@ read_char_minibuf_menu_prompt (int commandflag,
   /* FIXME: Use the minibuffer's frame width.  */
   ptrdiff_t width = FRAME_COLS (SELECTED_FRAME ()) - 4;
   ptrdiff_t idx = -1;
-  int nobindings = 1;
+  bool nobindings = 1;
   Lisp_Object rest, vector;
   char *menu;
 
@@ -8520,7 +8492,7 @@ read_char_minibuf_menu_prompt (int commandflag,
   /* Present the documented bindings, a line at a time.  */
   while (1)
     {
-      int notfirst = 0;
+      bool notfirst = 0;
       ptrdiff_t i = nlength;
       Lisp_Object obj;
       Lisp_Object orig_defn_macro;
@@ -8576,8 +8548,8 @@ read_char_minibuf_menu_prompt (int commandflag,
               /* Ignore the element if it has no prompt string.  */
               if (INTEGERP (event) && parse_menu_item (elt, -1))
                 {
-                  /* 1 if the char to type matches the string.  */
-                  int char_matches;
+                  /* True if the char to type matches the string.  */
+                  bool char_matches;
                   Lisp_Object upcased_event, downcased_event;
                   Lisp_Object desc = Qnil;
                   Lisp_Object s
@@ -8629,7 +8601,7 @@ read_char_minibuf_menu_prompt (int commandflag,
                           i += 2;
                         }
                       notfirst = 1;
-                      nobindings = 0 ;
+                      nobindings = 0;
 
                       /* If the char to type doesn't match the string's
                          first char, explicitly show what char to type.  */
@@ -8763,14 +8735,14 @@ typedef struct keyremap
 
 /* Lookup KEY in MAP.
    MAP is a keymap mapping keys to key vectors or functions.
-   If the mapping is a function and DO_FUNCTION is non-zero, then
+   If the mapping is a function and DO_FUNCALL is true,
    the function is called with PROMPT as parameter and its return
    value is used as the return value of this function (after checking
    that it is indeed a vector).  */
 
 static Lisp_Object
 access_keymap_keyremap (Lisp_Object map, Lisp_Object key, Lisp_Object prompt,
-                        int do_funcall)
+                        bool do_funcall)
 {
   Lisp_Object next;
 
@@ -8809,15 +8781,15 @@ access_keymap_keyremap (Lisp_Object map, Lisp_Object key, Lisp_Object prompt,
    BUFSIZE is its maximum size.
    FKEY is a pointer to the keyremap structure to use.
    INPUT is the index of the last element in KEYBUF.
-   DOIT if non-zero says that the remapping can actually take place.
+   DOIT if true says that the remapping can actually take place.
    DIFF is used to return the number of keys added/removed by the remapping.
    PARENT is the root of the keymap.
    PROMPT is the prompt to use if the remapping happens through a function.
-   The return value is non-zero if the remapping actually took place.  */
+   Return true if the remapping actually took place.  */
 
-static int
+static bool
 keyremap_step (Lisp_Object *keybuf, int bufsize, volatile keyremap *fkey,
-               int input, int doit, int *diff, Lisp_Object prompt)
+               int input, bool doit, int *diff, Lisp_Object prompt)
 {
   Lisp_Object next, key;
 
@@ -8871,7 +8843,7 @@ keyremap_step (Lisp_Object *keybuf, int bufsize, volatile keyremap *fkey,
   return 0;
 }
 
-static int
+static bool
 test_undefined (Lisp_Object binding)
 {
   return (EQ (binding, Qundefined)
@@ -8913,13 +8885,13 @@ test_undefined (Lisp_Object binding)
    off the switch-frame event until later; the next call to
    read_char will return it.
 
-   If FIX_CURRENT_BUFFER is nonzero, we restore current_buffer
+   If FIX_CURRENT_BUFFER, we restore current_buffer
    from the selected window's buffer.  */
 
 static int
 read_key_sequence (Lisp_Object *keybuf, int bufsize, Lisp_Object prompt,
-                   int dont_downcase_last, int can_return_switch_frame,
-                   int fix_current_buffer)
+                   bool dont_downcase_last, bool can_return_switch_frame,
+                   bool fix_current_buffer)
 {
   Lisp_Object from_string;
   ptrdiff_t count = SPECPDL_INDEX ();
@@ -8952,7 +8924,7 @@ read_key_sequence (Lisp_Object *keybuf, int bufsize, Lisp_Object prompt,
      key sequence.  */
   Lisp_Object orig_keymap;
 
-  /* 1 if we have already considered switching to the local-map property
+  /* Positive if we have already considered switching to the local-map property
      of the place where a mouse click occurred.  */
   int localized_local_map = 0;
 
@@ -8992,10 +8964,10 @@ read_key_sequence (Lisp_Object *keybuf, int bufsize, Lisp_Object prompt,
   /* Likewise, for key_translation_map and input-decode-map.  */
   keyremap keytran, indec;
 
-  /* Non-zero if we are trying to map a key by changing an upper-case
+  /* True if we are trying to map a key by changing an upper-case
      letter to lower case, or a shifted function key to an unshifted
      one.  */
-  int shift_translated = 0;
+  bool shift_translated = 0;
 
   /* If we receive a `switch-frame' or `select-window' event in the middle of
      a key sequence, we put it off for later.
@@ -9011,7 +8983,7 @@ read_key_sequence (Lisp_Object *keybuf, int bufsize, Lisp_Object prompt,
   int original_uppercase_position = -1;
 
   /* Gets around Microsoft compiler limitations.  */
-  int dummyflag = 0;
+  bool dummyflag = 0;
 
   struct buffer *starting_buffer;
 
@@ -9173,7 +9145,7 @@ read_key_sequence (Lisp_Object *keybuf, int bufsize, Lisp_Object prompt,
          : (/* indec.start < t || fkey.start < t || */ keytran.start < t))
     {
       Lisp_Object key;
-      int used_mouse_menu = 0;
+      bool used_mouse_menu = 0;
 
       /* Where the last real key started.  If we need to throw away a
          key that has expanded into more than one element of keybuf
@@ -9267,7 +9239,7 @@ read_key_sequence (Lisp_Object *keybuf, int bufsize, Lisp_Object prompt,
                    return.  Any better way to fix this? -- cyd  */
                 || (interrupted_kboard != current_kboard))
               {
-                int found = 0;
+                bool found = 0;
                 struct kboard *k;
 
                 for (k = all_kboards; k; k = k->next_kboard)
@@ -9821,7 +9793,8 @@ read_key_sequence (Lisp_Object *keybuf, int bufsize, Lisp_Object prompt,
       while (indec.end < t)
         {
           struct gcpro gcpro1, gcpro2, gcpro3, gcpro4;
-          int done, diff;
+          bool done;
+          int diff;
 
           GCPRO4 (indec.map, fkey.map, keytran.map, delayed_switch_frame);
           done = keyremap_step (keybuf, bufsize, &indec, max (t, mock_input),
@@ -9855,7 +9828,8 @@ read_key_sequence (Lisp_Object *keybuf, int bufsize, Lisp_Object prompt,
         while (fkey.end < indec.start)
           {
             struct gcpro gcpro1, gcpro2, gcpro3, gcpro4;
-            int done, diff;
+            bool done;
+            int diff;
 
             GCPRO4 (indec.map, fkey.map, keytran.map, delayed_switch_frame);
             done = keyremap_step (keybuf, bufsize, &fkey,
@@ -9884,7 +9858,8 @@ read_key_sequence (Lisp_Object *keybuf, int bufsize, Lisp_Object prompt,
       while (keytran.end < fkey.start)
         {
           struct gcpro gcpro1, gcpro2, gcpro3, gcpro4;
-          int done, diff;
+          bool done;
+          int diff;
 
           GCPRO4 (indec.map, fkey.map, keytran.map, delayed_switch_frame);
           done = keyremap_step (keybuf, bufsize, &keytran, max (t, mock_input),
@@ -10270,38 +10245,32 @@ a special event, so ignore the prefix argument and don't clear it.  */)
 
 
 
-/* Return nonzero if input events are pending.  */
+/* Return true if input events are pending.  */
 
-int
+bool
 detect_input_pending (void)
 {
-  if (!input_pending)
-    get_input_pending (&input_pending, 0);
-
-  return input_pending;
+  return input_pending || get_input_pending (0);
 }
 
-/* Return nonzero if input events other than mouse movements are
+/* Return true if input events other than mouse movements are
    pending.  */
 
-int
+bool
 detect_input_pending_ignore_squeezables (void)
 {
-  if (!input_pending)
-    get_input_pending (&input_pending, READABLE_EVENTS_IGNORE_SQUEEZABLES);
-
-  return input_pending;
+  return input_pending || get_input_pending (READABLE_EVENTS_IGNORE_SQUEEZABLES);
 }
 
-/* Return nonzero if input events are pending, and run any pending timers.  */
+/* Return true if input events are pending, and run any pending timers.  */
 
-int
-detect_input_pending_run_timers (int do_display)
+bool
+detect_input_pending_run_timers (bool do_display)
 {
-  int old_timers_run = timers_run;
+  unsigned old_timers_run = timers_run;
 
   if (!input_pending)
-    get_input_pending (&input_pending, READABLE_EVENTS_DO_TIMERS_NOW);
+    get_input_pending (READABLE_EVENTS_DO_TIMERS_NOW);
 
   if (old_timers_run != timers_run && do_display)
     {
@@ -10332,13 +10301,13 @@ clear_input_pending (void)
   input_pending = 0;
 }
 
-/* Return nonzero if there are pending requeued events.
+/* Return true if there are pending requeued events.
    This isn't used yet.  The hope is to make wait_reading_process_output
    call it, and return if it runs Lisp code that unreads something.
    The problem is, kbd_buffer_get_event needs to be fixed to know what
    to do in that case.  It isn't trivial.  */
 
-int
+bool
 requeued_events_pending_p (void)
 {
   return (!NILP (Vunread_command_events));
@@ -10359,10 +10328,9 @@ if there is a doubt, the value is t.  */)
   /* Process non-user-visible events (Bug#10195).  */
   process_special_events ();
 
-  get_input_pending (&input_pending,
-                     READABLE_EVENTS_DO_TIMERS_NOW
-                     | READABLE_EVENTS_FILTER_EVENTS);
-  return input_pending > 0 ? Qt : Qnil;
+  return (get_input_pending (READABLE_EVENTS_DO_TIMERS_NOW
+                             | READABLE_EVENTS_FILTER_EVENTS)
+          ? Qt : Qnil);
 }
 
 DEFUN ("recent-keys", Frecent_keys, Srecent_keys, 0, 0, 0,
@@ -10868,7 +10836,7 @@ handle_interrupt (bool in_signal_handler)
 /* Handle a C-g by making read_char return C-g.  */
 
 static void
-quit_throw_to_read_char (int from_signal)
+quit_throw_to_read_char (bool from_signal)
 {
   /* When not called from a signal handler it is safe to call
      Lisp.  */
@@ -10898,7 +10866,7 @@ otherwise Emacs uses CBREAK mode.
 See also `current-input-mode'.  */)
   (Lisp_Object interrupt)
 {
-  int new_interrupt_input;
+  bool new_interrupt_input;
 #ifdef USABLE_SIGIO
 #ifdef HAVE_X_WINDOWS
   if (x_display_list != NULL)
diff --git a/src/keyboard.h b/src/keyboard.h
index d78c27fbf9b..e57c8cc7193 100644
--- a/src/keyboard.h
+++ b/src/keyboard.h
@@ -169,12 +169,12 @@ struct kboard
        reading from this KBOARD again until more input arrives.  */
     char kbd_queue_has_data;
 
-    /* Nonzero means echo each character as typed.  */
-    char immediate_echo;
+    /* True means echo each character as typed.  */
+    unsigned immediate_echo : 1;
 
     /* If we have echoed a prompt string specified by the user,
        this is its length in characters.  Otherwise this is -1.  */
-    char echo_after_prompt;
+    ptrdiff_t echo_after_prompt;
   };
 
 KEYBOARD_INLINE void
@@ -463,14 +463,14 @@ extern Lisp_Object Qhelp_echo;
 extern Lisp_Object Qmode_line, Qvertical_line, Qheader_line;
 
 /* True while doing kbd input.  */
-extern int waiting_for_input;
+extern bool waiting_for_input;
 
 /* Address (if not 0) of EMACS_TIME to zero out if a SIGIO interrupt
    happens.  */
 extern EMACS_TIME *input_available_clear_time;
 
 #if defined HAVE_WINDOW_SYSTEM && !defined USE_GTK && !defined HAVE_NS
-extern int ignore_mouse_drag_p;
+extern bool ignore_mouse_drag_p;
 #endif
 
 /* The primary selection.  */
@@ -482,7 +482,7 @@ struct input_event;
 extern Lisp_Object parse_modifiers (Lisp_Object);
 extern Lisp_Object reorder_modifiers (Lisp_Object);
 extern Lisp_Object read_char (int, ptrdiff_t, Lisp_Object *, Lisp_Object,
-                              int *, EMACS_TIME *);
+                              bool *, EMACS_TIME *);
 extern int parse_solitary_modifier (Lisp_Object symbol);
 
 
@@ -506,10 +506,10 @@ extern Time last_event_timestamp;
 
 extern int quit_char;
 
-extern int timers_run;
+extern unsigned int timers_run;
 
-extern int menu_separator_name_p (const char *);
-extern int parse_menu_item (Lisp_Object, int);
+extern bool menu_separator_name_p (const char *);
+extern bool parse_menu_item (Lisp_Object, int);
 
 extern void init_kboard (KBOARD *);
 extern void delete_kboard (KBOARD *);
@@ -524,15 +524,15 @@ extern void start_polling (void);
 extern void stop_polling (void);
 extern void set_poll_suppress_count (int);
 extern int gobble_input (void);
-extern int input_polling_used (void);
+extern bool input_polling_used (void);
 extern void clear_input_pending (void);
-extern int requeued_events_pending_p (void);
+extern bool requeued_events_pending_p (void);
 extern void bind_polling_period (int);
 extern int make_ctrl_char (int) ATTRIBUTE_CONST;
 extern void stuff_buffered_input (Lisp_Object);
 extern void clear_waiting_for_input (void);
-extern void swallow_events (int);
-extern int lucid_event_type_list_p (Lisp_Object);
+extern void swallow_events (bool);
+extern bool lucid_event_type_list_p (Lisp_Object);
 extern void kbd_buffer_store_event (struct input_event *);
 extern void kbd_buffer_store_event_hold (struct input_event *,
                                          struct input_event *);
@@ -544,7 +544,7 @@ extern void gen_help_event (Lisp_Object, Lisp_Object, Lisp_Object,
                             Lisp_Object, ptrdiff_t);
 extern void kbd_buffer_store_help_event (Lisp_Object, Lisp_Object);
 extern Lisp_Object menu_item_eval_property (Lisp_Object);
-extern int  kbd_buffer_events_waiting (int);
+extern bool kbd_buffer_events_waiting (void);
 extern void add_user_signal (int, const char *);
 
 extern int tty_read_avail_input (struct terminal *, struct input_event *);
diff --git a/src/keymap.c b/src/keymap.c
index 6ea142651bf..fbdd31e0de3 100644
--- a/src/keymap.c
+++ b/src/keymap.c
@@ -99,12 +99,12 @@ static void describe_command (Lisp_Object, Lisp_Object);
 static void describe_translation (Lisp_Object, Lisp_Object);
 static void describe_map (Lisp_Object, Lisp_Object,
                           void (*) (Lisp_Object, Lisp_Object),
-                          int, Lisp_Object, Lisp_Object*, int, int);
+                          bool, Lisp_Object, Lisp_Object*, bool, bool);
 static void describe_vector (Lisp_Object, Lisp_Object, Lisp_Object,
-                             void (*) (Lisp_Object, Lisp_Object), int,
-                             Lisp_Object, Lisp_Object, int, int);
+                             void (*) (Lisp_Object, Lisp_Object), bool,
+                             Lisp_Object, Lisp_Object, bool, bool);
 static void silly_event_symbol_error (Lisp_Object);
-static Lisp_Object get_keyelt (Lisp_Object, int);
+static Lisp_Object get_keyelt (Lisp_Object, bool);
 
 /* Keymap object support - constructors and predicates.                 */
 
@@ -207,15 +207,12 @@ when reading a key-sequence to be looked-up in this keymap.  */)
 /* Check that OBJECT is a keymap (after dereferencing through any
    symbols).  If it is, return it.
 
-   If AUTOLOAD is non-zero and OBJECT is a symbol whose function value
+   If AUTOLOAD and if OBJECT is a symbol whose function value
    is an autoload form, do the autoload and try again.
-   If AUTOLOAD is nonzero, callers must assume GC is possible.
-
-   If the map needs to be autoloaded, but AUTOLOAD is zero (and ERROR
-   is zero as well), return Qt.
+   If AUTOLOAD, callers must assume GC is possible.
 
    ERROR_IF_NOT_KEYMAP controls how we respond if OBJECT isn't a keymap.
-   If ERROR_IF_NOT_KEYMAP is non-zero, signal an error; otherwise,
+   If ERROR_IF_NOT_KEYMAP, signal an error; otherwise,
    just return Qnil.
 
    Note that most of the time, we don't want to pursue autoloads.
@@ -224,11 +221,11 @@ when reading a key-sequence to be looked-up in this keymap.  */)
    but it seems to me that only read_key_sequence, Flookup_key, and
    Fdefine_key should cause keymaps to be autoloaded.
 
-   This function can GC when AUTOLOAD is non-zero, because it calls
+   This function can GC when AUTOLOAD is true, because it calls
    Fautoload_do_load which can GC.  */
 
 Lisp_Object
-get_keymap (Lisp_Object object, int error_if_not_keymap, int autoload)
+get_keymap (Lisp_Object object, bool error_if_not_keymap, bool autoload)
 {
   Lisp_Object tem;
 
@@ -280,7 +277,7 @@ get_keymap (Lisp_Object object, int error_if_not_keymap, int autoload)
    We assume that KEYMAP is a valid keymap.  */
 
 static Lisp_Object
-keymap_parent (Lisp_Object keymap, int autoload)
+keymap_parent (Lisp_Object keymap, bool autoload)
 {
   Lisp_Object list;
 
@@ -307,7 +304,7 @@ If KEYMAP has no parent, return nil.  */)
 }
 
 /* Check whether MAP is one of MAPS parents.  */
-static int
+static bool
 keymap_memberp (Lisp_Object map, Lisp_Object maps)
 {
   if (NILP (map)) return 0;
@@ -365,19 +362,20 @@ Return PARENT.  PARENT should be nil or another keymap.  */)
 
    MAP must be a keymap or a list of keymaps.
 
-   If T_OK is non-zero, bindings for Qt are treated as default
+   If T_OK, bindings for Qt are treated as default
    bindings; any key left unmentioned by other tables and bindings is
    given the binding of Qt.
 
-   If T_OK is zero, bindings for Qt are not treated specially.
+   If not T_OK, bindings for Qt are not treated specially.
 
    If NOINHERIT, don't accept a subkeymap found in an inherited keymap.
 
-   Returns Qunbound if no binding was found (and returns Qnil if a nil
+   Return Qunbound if no binding was found (and return Qnil if a nil
    binding was found).  */
 
 static Lisp_Object
-access_keymap_1 (Lisp_Object map, Lisp_Object idx, int t_ok, int noinherit, int autoload)
+access_keymap_1 (Lisp_Object map, Lisp_Object idx,
+                 bool t_ok, bool noinherit, bool autoload)
 {
   /* If idx is a list (some sort of mouse click, perhaps?),
      the index we want to use is the car of the list, which
@@ -547,7 +545,7 @@ access_keymap_1 (Lisp_Object map, Lisp_Object idx, int t_ok, int noinherit, int
 
 Lisp_Object
 access_keymap (Lisp_Object map, Lisp_Object idx,
-               int t_ok, int noinherit, int autoload)
+               bool t_ok, bool noinherit, bool autoload)
 {
   Lisp_Object val = access_keymap_1 (map, idx, t_ok, noinherit, autoload);
   return EQ (val, Qunbound) ? Qnil : val;
@@ -630,9 +628,10 @@ map_keymap_call (Lisp_Object key, Lisp_Object val, Lisp_Object fun, void *dummy)
 }
 
 /* Same as map_keymap_internal, but traverses parent keymaps as well.
-   A non-zero AUTOLOAD indicates that autoloaded keymaps should be loaded.  */
+   AUTOLOAD indicates that autoloaded keymaps should be loaded.  */
 void
-map_keymap (Lisp_Object map, map_keymap_function_t fun, Lisp_Object args, void *data, int autoload)
+map_keymap (Lisp_Object map, map_keymap_function_t fun, Lisp_Object args,
+            void *data, bool autoload)
 {
   struct gcpro gcpro1;
   GCPRO1 (args);
@@ -711,13 +710,13 @@ usage: (map-keymap FUNCTION KEYMAP)  */)
    Also if OBJECT has a menu string as the first element,
    remove that.  Also remove a menu help string as second element.
 
-   If AUTOLOAD is nonzero, load autoloadable keymaps
+   If AUTOLOAD, load autoloadable keymaps
    that are referred to with indirection.
 
    This can GC because menu_item_eval_property calls Feval.  */
 
 static Lisp_Object
-get_keyelt (Lisp_Object object, int autoload)
+get_keyelt (Lisp_Object object, bool autoload)
 {
   while (1)
     {
@@ -1114,10 +1113,10 @@ binding is altered.  If there is no binding for KEY, the new pair
 binding KEY to DEF is added at the front of KEYMAP.  */)
   (Lisp_Object keymap, Lisp_Object key, Lisp_Object def)
 {
-  register ptrdiff_t idx;
-  register Lisp_Object c;
-  register Lisp_Object cmd;
-  int metized = 0;
+  ptrdiff_t idx;
+  Lisp_Object c;
+  Lisp_Object cmd;
+  bool metized = 0;
   int meta_bit;
   ptrdiff_t length;
   struct gcpro gcpro1, gcpro2, gcpro3;
@@ -1271,11 +1270,11 @@ third optional argument ACCEPT-DEFAULT is non-nil, `lookup-key' will
 recognize the default bindings, just as `read-key-sequence' does.  */)
   (Lisp_Object keymap, Lisp_Object key, Lisp_Object accept_default)
 {
-  register ptrdiff_t idx;
-  register Lisp_Object cmd;
-  register Lisp_Object c;
+  ptrdiff_t idx;
+  Lisp_Object cmd;
+  Lisp_Object c;
   ptrdiff_t length;
-  int t_ok = !NILP (accept_default);
+  bool t_ok = !NILP (accept_default);
   struct gcpro gcpro1, gcpro2;
 
   GCPRO2 (keymap, key);
@@ -1887,7 +1886,7 @@ DEFUN ("current-minor-mode-maps", Fcurrent_minor_mode_maps, Scurrent_minor_mode_
 struct accessible_keymaps_data {
   Lisp_Object maps, tail, thisseq;
   /* Does the current sequence end in the meta-prefix-char?  */
-  int is_metized;
+  bool is_metized;
 };
 
 static void
@@ -1898,7 +1897,7 @@ accessible_keymaps_1 (Lisp_Object key, Lisp_Object cmd, Lisp_Object args, void *
   Lisp_Object maps = d->maps;
   Lisp_Object tail = d->tail;
   Lisp_Object thisseq = d->thisseq;
-  int is_metized = d->is_metized && INTEGERP (key);
+  bool is_metized = d->is_metized && INTEGERP (key);
   Lisp_Object tem;
 
   cmd = get_keymap (get_keyelt (cmd, 0), 0, 0);
@@ -2060,7 +2059,7 @@ The `kbd' macro is an approximate inverse of this.  */)
   Lisp_Object sep = build_string (" ");
   Lisp_Object key;
   Lisp_Object result;
-  int add_meta = 0;
+  bool add_meta = 0;
   USE_SAFE_ALLOCA;
 
   if (!NILP (prefix))
@@ -2155,9 +2154,10 @@ The `kbd' macro is an approximate inverse of this.  */)
 
 
 char *
-push_key_description (EMACS_INT ch, char *p, int force_multibyte)
+push_key_description (EMACS_INT ch, char *p)
 {
-  int c, c2, tab_as_ci;
+  int c, c2;
+  bool tab_as_ci;
 
   /* Clear all the meaningless bits above the meta bit.  */
   c = ch & (meta_modifier | ~ - meta_modifier);
@@ -2256,21 +2256,12 @@ push_key_description (EMACS_INT ch, char *p, int force_multibyte)
       *p++ = 'P';
       *p++ = 'C';
     }
-  else if (c < 128
-           || (NILP (BVAR (current_buffer, enable_multibyte_characters))
-               && SINGLE_BYTE_CHAR_P (c)
-               && !force_multibyte))
-    {
-      *p++ = c;
-    }
+  else if (c < 128)
+    *p++ = c;
   else
     {
       /* Now we are sure that C is a valid character code.  */
-      if (NILP (BVAR (current_buffer, enable_multibyte_characters))
-          && ! force_multibyte)
-        *p++ = multibyte_char_to_unibyte (c);
-      else
-        p += CHAR_STRING (c, (unsigned char *) p);
+      p += CHAR_STRING (c, (unsigned char *) p);
     }
 
   return p;
@@ -2299,9 +2290,8 @@ around function keys and event symbols.  */)
 
   if (INTEGERP (key))           /* Normal character.  */
     {
-      char tem[KEY_DESCRIPTION_SIZE], *p;
-
-      p = push_key_description (XINT (key), tem, 1);
+      char tem[KEY_DESCRIPTION_SIZE];
+      char *p = push_key_description (XINT (key), tem);
       *p = 0;
       return make_specified_string (tem, -1, p - tem, 1);
     }
@@ -2429,7 +2419,7 @@ static void where_is_internal_1 (Lisp_Object key, Lisp_Object binding,
 
 static Lisp_Object
 shadow_lookup (Lisp_Object shadow, Lisp_Object key, Lisp_Object flag,
-               int remap)
+               bool remap)
 {
   Lisp_Object tail, value;
 
@@ -2461,7 +2451,7 @@ static Lisp_Object Vmouse_events;
 
 struct where_is_internal_data {
   Lisp_Object definition, this, last;
-  int last_is_meta, noindirect;
+  bool last_is_meta, noindirect;
   Lisp_Object sequences;
 };
 
@@ -2474,7 +2464,7 @@ struct where_is_internal_data {
 
 static Lisp_Object
 where_is_internal (Lisp_Object definition, Lisp_Object keymaps,
-                   int noindirect, int nomenus)
+                   bool noindirect, bool nomenus)
 {
   Lisp_Object maps = Qnil;
   Lisp_Object found;
@@ -2523,7 +2513,7 @@ where_is_internal (Lisp_Object definition, Lisp_Object keymaps,
          [M-CHAR] sequences, check if last character of the sequence
          is the meta-prefix char.  */
       Lisp_Object last;
-      int last_is_meta;
+      bool last_is_meta;
 
       this = Fcar (XCAR (maps));
       map  = Fcdr (XCAR (maps));
@@ -2606,7 +2596,7 @@ The optional 5th arg NO-REMAP alters how command remapping is handled:
     /* Actually relevant bindings.  */
   Lisp_Object found = Qnil;
   /* 1 means ignore all menu bindings entirely.  */
-  int nomenus = !NILP (firstonly) && !EQ (firstonly, Qnon_ascii);
+  bool nomenus = !NILP (firstonly) && !EQ (firstonly, Qnon_ascii);
   struct gcpro gcpro1, gcpro2, gcpro3, gcpro4, gcpro5, gcpro6;
   /* List of sequences found via remapping.  Keep them in a separate
      variable, so as to push them later, since we prefer
@@ -2615,7 +2605,7 @@ The optional 5th arg NO-REMAP alters how command remapping is handled:
   /* Whether or not we're handling remapped sequences.  This is needed
      because remapping is not done recursively by Fcommand_remapping: you
      can't remap a remapped command.  */
-  int remapped = 0;
+  bool remapped = 0;
   Lisp_Object tem = Qnil;
 
   /* Refresh the C version of the modifier preference.  */
@@ -2767,10 +2757,10 @@ where_is_internal_1 (Lisp_Object key, Lisp_Object binding, Lisp_Object args, voi
 {
   struct where_is_internal_data *d = data; /* Cast! */
   Lisp_Object definition = d->definition;
-  int noindirect = d->noindirect;
+  bool noindirect = d->noindirect;
   Lisp_Object this = d->this;
   Lisp_Object last = d->last;
-  int last_is_meta = d->last_is_meta;
+  bool last_is_meta = d->last_is_meta;
   Lisp_Object sequence;
 
   /* Search through indirections unless that's not wanted.  */
@@ -2821,8 +2811,8 @@ The optional argument MENUS, if non-nil, says to mention menu bindings.
   (Lisp_Object buffer, Lisp_Object prefix, Lisp_Object menus)
 {
   Lisp_Object outbuf, shadow;
-  int nomenu = NILP (menus);
-  register Lisp_Object start1;
+  bool nomenu = NILP (menus);
+  Lisp_Object start1;
   struct gcpro gcpro1;
 
   const char *alternate_heading
@@ -2857,10 +2847,10 @@ You type        Translation\n\
                 alternate_heading = 0;
               }
 
-            bufend = push_key_description (translate[c], buf, 1);
+            bufend = push_key_description (translate[c], buf);
             insert (buf, bufend - buf);
             Findent_to (make_number (16), make_number (1));
-            bufend = push_key_description (c, buf, 1);
+            bufend = push_key_description (c, buf);
             insert (buf, bufend - buf);
 
             insert ("\n", 1);
@@ -2977,34 +2967,34 @@ You type        Translation\n\
 
 /* Insert a description of the key bindings in STARTMAP,
     followed by those of all maps reachable through STARTMAP.
-   If PARTIAL is nonzero, omit certain "uninteresting" commands
+   If PARTIAL, omit certain "uninteresting" commands
     (such as `undefined').
    If SHADOW is non-nil, it is a list of maps;
     don't mention keys which would be shadowed by any of them.
    PREFIX, if non-nil, says mention only keys that start with PREFIX.
    TITLE, if not 0, is a string to insert at the beginning.
    TITLE should not end with a colon or a newline; we supply that.
-   If NOMENU is not 0, then omit menu-bar commands.
+   If NOMENU, then omit menu-bar commands.
 
-   If TRANSL is nonzero, the definitions are actually key translations
+   If TRANSL, the definitions are actually key translations
    so print strings and vectors differently.
 
-   If ALWAYS_TITLE is nonzero, print the title even if there are no maps
+   If ALWAYS_TITLE, print the title even if there are no maps
    to look through.
 
-   If MENTION_SHADOW is nonzero, then when something is shadowed by SHADOW,
+   If MENTION_SHADOW, then when something is shadowed by SHADOW,
    don't omit it; instead, mention it but say it is shadowed.
 
    Any inserted text ends in two newlines (used by `help-make-xrefs').  */
 
 void
-describe_map_tree (Lisp_Object startmap, int partial, Lisp_Object shadow,
-                   Lisp_Object prefix, const char *title, int nomenu, int transl,
-                   int always_title, int mention_shadow)
+describe_map_tree (Lisp_Object startmap, bool partial, Lisp_Object shadow,
+                   Lisp_Object prefix, const char *title, bool nomenu,
+                   bool transl, bool always_title, bool mention_shadow)
 {
   Lisp_Object maps, orig_maps, seen, sub_shadows;
   struct gcpro gcpro1, gcpro2, gcpro3;
-  int something = 0;
+  bool something = 0;
   const char *key_heading
     = "\
 key             binding\n\
@@ -3179,7 +3169,12 @@ describe_translation (Lisp_Object definition, Lisp_Object args)
    into an array of `struct describe_map_elt',
    then sorts them by the events.  */
 
-struct describe_map_elt { Lisp_Object event; Lisp_Object definition; int shadowed; };
+struct describe_map_elt
+{
+  Lisp_Object event;
+  Lisp_Object definition;
+  bool shadowed;
+};
 
 /* qsort comparison function for sorting `struct describe_map_elt' by
    the event field.  */
@@ -3209,14 +3204,14 @@ describe_map_compare (const void *aa, const void *bb)
 static void
 describe_map (Lisp_Object map, Lisp_Object prefix,
               void (*elt_describer) (Lisp_Object, Lisp_Object),
-              int partial, Lisp_Object shadow,
-              Lisp_Object *seen, int nomenu, int mention_shadow)
+              bool partial, Lisp_Object shadow,
+              Lisp_Object *seen, bool nomenu, bool mention_shadow)
 {
   Lisp_Object tail, definition, event;
   Lisp_Object tem;
   Lisp_Object suppress;
   Lisp_Object kludge;
-  int first = 1;
+  bool first = 1;
   struct gcpro gcpro1, gcpro2, gcpro3;
 
   /* These accumulate the values from sparse keymap bindings,
@@ -3258,7 +3253,7 @@ describe_map (Lisp_Object map, Lisp_Object prefix,
                          1, mention_shadow);
       else if (CONSP (XCAR (tail)))
         {
-          int this_shadowed = 0;
+          bool this_shadowed = 0;
 
           event = XCAR (XCAR (tail));
 
@@ -3428,7 +3423,7 @@ DESCRIBER is the output function used; nil means use `princ'.  */)
    of bytes that lead to the character set or portion of a character
    set described by this chartable.
 
-   If PARTIAL is nonzero, it means do not mention suppressed commands
+   If PARTIAL, it means do not mention suppressed commands
    (that assumes the vector is in a keymap).
 
    SHADOW is a list of keymaps that shadow this map.
@@ -3448,8 +3443,8 @@ DESCRIBER is the output function used; nil means use `princ'.  */)
 static void
 describe_vector (Lisp_Object vector, Lisp_Object prefix, Lisp_Object args,
                  void (*elt_describer) (Lisp_Object, Lisp_Object),
-                 int partial, Lisp_Object shadow, Lisp_Object entire_map,
-                 int keymap_p, int mention_shadow)
+                 bool partial, Lisp_Object shadow, Lisp_Object entire_map,
+                 bool keymap_p, bool mention_shadow)
 {
   Lisp_Object definition;
   Lisp_Object tem2;
@@ -3457,7 +3452,7 @@ describe_vector (Lisp_Object vector, Lisp_Object prefix, Lisp_Object args,
   int i;
   Lisp_Object suppress;
   Lisp_Object kludge;
-  int first = 1;
+  bool first = 1;
   struct gcpro gcpro1, gcpro2, gcpro3, gcpro4;
   /* Range of elements to be handled.  */
   int from, to, stop;
@@ -3497,7 +3492,7 @@ describe_vector (Lisp_Object vector, Lisp_Object prefix, Lisp_Object args,
 
   for (i = from; ; i++)
     {
-      int this_shadowed = 0;
+      bool this_shadowed = 0;
       int range_beg, range_end;
       Lisp_Object val;
 
diff --git a/src/keymap.h b/src/keymap.h
index 5ed70c67b85..c704ee0b050 100644
--- a/src/keymap.h
+++ b/src/keymap.h
@@ -34,11 +34,11 @@ extern Lisp_Object Qkeymap, Qmenu_bar;
 extern Lisp_Object Qremap;
 extern Lisp_Object Qmenu_item;
 extern Lisp_Object current_global_map;
-extern char *push_key_description (EMACS_INT, char *, int);
-extern Lisp_Object access_keymap (Lisp_Object, Lisp_Object, int, int, int);
-extern Lisp_Object get_keymap (Lisp_Object, int, int);
-extern void describe_map_tree (Lisp_Object, int, Lisp_Object, Lisp_Object,
-                              const char *, int, int, int, int);
+extern char *push_key_description (EMACS_INT, char *);
+extern Lisp_Object access_keymap (Lisp_Object, Lisp_Object, bool, bool, bool);
+extern Lisp_Object get_keymap (Lisp_Object, bool, bool);
+extern void describe_map_tree (Lisp_Object, bool, Lisp_Object, Lisp_Object,
+                               const char *, bool, bool, bool, bool);
 extern ptrdiff_t current_minor_maps (Lisp_Object **, Lisp_Object **);
 extern void initial_define_key (Lisp_Object, int, const char *);
 extern void initial_define_lispy_key (Lisp_Object, const char *, const char *);
@@ -47,7 +47,8 @@ extern void keys_of_keymap (void);
 
 typedef void (*map_keymap_function_t)
      (Lisp_Object key, Lisp_Object val, Lisp_Object args, void* data);
-extern void map_keymap (Lisp_Object map, map_keymap_function_t fun, Lisp_Object largs, void* cargs, int autoload);
+extern void map_keymap (Lisp_Object, map_keymap_function_t, Lisp_Object,
+                        void *, bool);
 extern void map_keymap_canonical (Lisp_Object map,
                                   map_keymap_function_t fun,
                                   Lisp_Object args, void *data);
diff --git a/src/lisp.h b/src/lisp.h
index 71e542cc769..1de9ec74d9f 100644
--- a/src/lisp.h
+++ b/src/lisp.h
@@ -3198,9 +3198,9 @@ extern ptrdiff_t fast_string_match_ignore_case (Lisp_Object, Lisp_Object);
 extern ptrdiff_t fast_looking_at (Lisp_Object, ptrdiff_t, ptrdiff_t,
                                   ptrdiff_t, ptrdiff_t, Lisp_Object);
 extern ptrdiff_t scan_buffer (int, ptrdiff_t, ptrdiff_t, ptrdiff_t,
-                              ptrdiff_t *, int);
+                              ptrdiff_t *, bool);
 extern EMACS_INT scan_newline (ptrdiff_t, ptrdiff_t, ptrdiff_t, ptrdiff_t,
-                               EMACS_INT, int);
+                               EMACS_INT, bool);
 extern ptrdiff_t find_next_newline (ptrdiff_t, int);
 extern ptrdiff_t find_next_newline_no_quit (ptrdiff_t, ptrdiff_t);
 extern ptrdiff_t find_before_next_newline (ptrdiff_t, ptrdiff_t, ptrdiff_t);
@@ -3243,7 +3243,7 @@ extern Lisp_Object Qdisabled, QCfilter;
 extern Lisp_Object Qup, Qdown, Qbottom;
 extern Lisp_Object Qtop;
 extern Lisp_Object last_undo_boundary;
-extern int input_pending;
+extern bool input_pending;
 extern Lisp_Object menu_bar_items (Lisp_Object);
 extern Lisp_Object tool_bar_items (Lisp_Object, int *);
 extern void discard_mouse_events (void);
@@ -3251,9 +3251,9 @@ extern void discard_mouse_events (void);
 void handle_input_available_signal (int);
 #endif
 extern Lisp_Object pending_funcalls;
-extern int detect_input_pending (void);
-extern int detect_input_pending_ignore_squeezables (void);
-extern int detect_input_pending_run_timers (int);
+extern bool detect_input_pending (void);
+extern bool detect_input_pending_ignore_squeezables (void);
+extern bool detect_input_pending_run_timers (bool);
 extern void safe_run_hooks (Lisp_Object);
 extern void cmd_error_internal (Lisp_Object, const char *);
 extern Lisp_Object command_loop_1 (void);
@@ -3332,7 +3332,7 @@ extern bool running_asynch_code;
 extern Lisp_Object QCtype, Qlocal;
 extern Lisp_Object Qprocessp;
 extern void kill_buffer_processes (Lisp_Object);
-extern int wait_reading_process_output (intmax_t, int, int, int,
+extern int wait_reading_process_output (intmax_t, int, int, bool,
                                         Lisp_Object,
                                         struct Lisp_Process *,
                                         int);
@@ -3559,7 +3559,8 @@ extern char *emacs_root_dir (void);
    Used during startup to detect startup of dumped Emacs.  */
 extern bool initialized;
 
-extern int immediate_quit;          /* Nonzero means ^G can quit instantly.  */
+/* True means ^G can quit instantly.  */
+extern bool immediate_quit;
 
 extern void *xmalloc (size_t);
 extern void *xzalloc (size_t);
diff --git a/src/menu.c b/src/menu.c
index 835267b2f0c..6e052dc65a9 100644
--- a/src/menu.c
+++ b/src/menu.c
@@ -331,7 +331,7 @@ single_menu_item (Lisp_Object key, Lisp_Object item, Lisp_Object dummy, void *sk
 {
   Lisp_Object map, item_string, enabled;
   struct gcpro gcpro1, gcpro2;
-  int res;
+  bool res;
   struct skp *skp = skp_v;
 
   /* Parse the menu item and leave the result in item_properties.  */
diff --git a/src/nsmenu.m b/src/nsmenu.m
index 9af732c6c45..df8b3ea3e54 100644
--- a/src/nsmenu.m
+++ b/src/nsmenu.m
@@ -129,7 +129,7 @@ ns_update_menubar (struct frame *f, bool deep_p, EmacsMenu *submenu)
   BOOL needsSet = NO;
   const char *submenuTitle = [[submenu title] UTF8String];
   extern int waiting_for_input;
-  int owfi;
+  bool owfi;
   Lisp_Object items;
   widget_value *wv, *first_wv, *prev_wv = 0;
   int i;
diff --git a/src/process.c b/src/process.c
index c941a196539..2cbce9d28ea 100644
--- a/src/process.c
+++ b/src/process.c
@@ -4302,7 +4302,7 @@ wait_reading_process_output_1 (void)
      -1 meaning caller will actually read the input, so don't throw to
        the quit handler, or
 
-   DO_DISPLAY != 0 means redisplay should be done to show subprocess
+   DO_DISPLAY means redisplay should be done to show subprocess
      output that arrives.
 
    If WAIT_FOR_CELL is a cons cell, wait until its car is non-nil
@@ -4322,7 +4322,7 @@ wait_reading_process_output_1 (void)
 
 int
 wait_reading_process_output (intmax_t time_limit, int nsecs, int read_kbd,
-                             int do_display,
+                             bool do_display,
                              Lisp_Object wait_for_cell,
                              struct Lisp_Process *wait_proc, int just_wait_proc)
 {
@@ -4419,7 +4419,7 @@ wait_reading_process_output (intmax_t time_limit, int nsecs, int read_kbd,
 
           do
             {
-              int old_timers_run = timers_run;
+              unsigned old_timers_run = timers_run;
               struct buffer *old_buffer = current_buffer;
               Lisp_Object old_window = selected_window;
 
@@ -4753,7 +4753,7 @@ wait_reading_process_output (intmax_t time_limit, int nsecs, int read_kbd,
 
       if (read_kbd != 0)
         {
-          int old_timers_run = timers_run;
+          unsigned old_timers_run = timers_run;
           struct buffer *old_buffer = current_buffer;
           Lisp_Object old_window = selected_window;
           int leave = 0;
@@ -6821,14 +6821,14 @@ extern int sys_select (int, SELECT_TYPE *, SELECT_TYPE *, SELECT_TYPE *,
    see full version for other parameters. We know that wait_proc will
      always be NULL, since `subprocesses' isn't defined.
 
-   DO_DISPLAY != 0 means redisplay should be done to show subprocess
+   DO_DISPLAY means redisplay should be done to show subprocess
    output that arrives.
 
    Return true if we received input from any process.  */
 
 int
 wait_reading_process_output (intmax_t time_limit, int nsecs, int read_kbd,
-                             int do_display,
+                             bool do_display,
                              Lisp_Object wait_for_cell,
                              struct Lisp_Process *wait_proc, int just_wait_proc)
 {
@@ -6904,7 +6904,7 @@ wait_reading_process_output (intmax_t time_limit, int nsecs, int read_kbd,
 
           do
             {
-              int old_timers_run = timers_run;
+              unsigned old_timers_run = timers_run;
               timer_delay = timer_check ();
               if (timers_run != old_timers_run && do_display)
                 /* We must retry, since a timer may have requeued itself
diff --git a/src/search.c b/src/search.c
index 7c084c62e28..aacdbe33eef 100644
--- a/src/search.c
+++ b/src/search.c
@@ -636,12 +636,12 @@ newline_cache_on_off (struct buffer *buf)
    If we don't find COUNT instances before reaching END, set *SHORTAGE
    to the number of TARGETs left unfound, and return END.
 
-   If ALLOW_QUIT is non-zero, set immediate_quit.  That's good to do
+   If ALLOW_QUIT, set immediate_quit.  That's good to do
    except when inside redisplay.  */
 
 ptrdiff_t
-scan_buffer (register int target, ptrdiff_t start, ptrdiff_t end,
-             ptrdiff_t count, ptrdiff_t *shortage, int allow_quit)
+scan_buffer (int target, ptrdiff_t start, ptrdiff_t end,
+             ptrdiff_t count, ptrdiff_t *shortage, bool allow_quit)
 {
   struct region_cache *newline_cache;
   int direction;
@@ -837,23 +837,23 @@ scan_buffer (register int target, ptrdiff_t start, ptrdiff_t end,
    the number of line boundaries left unfound, and position at
    the limit we bumped up against.
 
-   If ALLOW_QUIT is non-zero, set immediate_quit.  That's good to do
+   If ALLOW_QUIT, set immediate_quit.  That's good to do
    except in special cases.  */
 
 EMACS_INT
 scan_newline (ptrdiff_t start, ptrdiff_t start_byte,
               ptrdiff_t limit, ptrdiff_t limit_byte,
-              register EMACS_INT count, int allow_quit)
+              EMACS_INT count, bool allow_quit)
 {
   int direction = ((count > 0) ? 1 : -1);
 
-  register unsigned char *cursor;
+  unsigned char *cursor;
   unsigned char *base;
 
   ptrdiff_t ceiling;
-  register unsigned char *ceiling_addr;
+  unsigned char *ceiling_addr;
 
-  int old_immediate_quit = immediate_quit;
+  bool old_immediate_quit = immediate_quit;
 
   /* The code that follows is like scan_buffer
      but checks for either newline or carriage return.  */
diff --git a/src/termopts.h b/src/termopts.h
index 49588ef0cbd..05fa0a52eee 100644
--- a/src/termopts.h
+++ b/src/termopts.h
@@ -18,7 +18,7 @@ along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.  */
 
 
 /* Nonzero means use interrupt-driven input.  */
-extern int interrupt_input;
+extern bool interrupt_input;
 
 /* Nonzero while interrupts are temporarily deferred during redisplay.  */
-extern int interrupts_deferred;
+extern bool interrupts_deferred;