--- a/src/signal.c	Fri Mar 08 13:33:14 2002 +0000
+++ b/src/signal.c	Wed Mar 13 08:54:06 2002 +0000
@@ -183,10 +183,14 @@
   int interval_id;
   int wakeup_id;
   Lisp_Object fun, arg;
+  /* Avoid any possibility of GC during QUIT */
+  int specco = begin_gc_forbidden ();
 
   /* No checks for Vinhibit_quit here or anywhere else in this file!!!
      Otherwise critical quit will not work right.
-     The only check for Vinhibit_quit is in QUIT itself. */
+     The only check for Vinhibit_quit is in QUIT itself.
+
+     (#### ???? I don't quite understand this comment.) */
   interval_id = pop_low_level_timeout (&async_timer_queue, 0);
 
   reset_interval_timer ();
@@ -213,6 +217,8 @@
 			   fun, arg);
 
   waiting_for_user_input_p = 0;
+
+  unbind_to (specco);
 }
 
 /* The following two functions are the external interface onto
@@ -410,17 +416,6 @@
     }
 }
 
-/* Cheesy but workable implementation of sleep() that doesn't
-   interfere with our periodic timers. */
-
-void
-emacs_sleep (int secs)
-{
-  stop_interrupts ();
-  sleep (secs);
-  start_interrupts ();
-}
-
 
 /**********************************************************************/
 /*                 The mechanism that drives it all                   */
@@ -432,6 +427,12 @@
 int
 check_what_happened (void)
 {
+  /* No GC can happen anywhere here.  handle_async_timeout_signal()
+     prevents GC (from asynch timeout handler), so does check_quit()
+     (from processing a message such as WM_INITMENU as a result of
+     draining the message queue).  establish_slow_interrupt_timer() is
+     too low-level to do anything that might invoke QUIT or call Lisp
+     code. */
   something_happened = 0;
   if (async_timeout_happened)
     {
@@ -638,13 +639,25 @@
   return Qnil;
 }
 
-void
+/* Defer all checking or processing of C-g.  You can do this, for example,
+   if you want to read C-g's as events. (In that case, you should set
+   Vquit_flag to Qnil just before you unbind, because it typically gets set
+   as a result of reading C-g.) */
+
+int
 begin_dont_check_for_quit (void)
 {
+  int depth = specpdl_depth ();
+  /* As an optimization in QUIT_FLAG_SAYS_SHOULD_QUIT, we bind inhibit-quit
+     to t -- it has to be checked anyway, and by doing this, we only need
+     to check dont_check_for_quit when quit-flag == `critical', which is
+     rare. */
   specbind (Qinhibit_quit, Qt);
   record_unwind_protect (restore_dont_check_for_quit,
 			 make_int (dont_check_for_quit));
   dont_check_for_quit = 1;
+
+  return depth;
 }
 
 /* The effect of this function is to set Vquit_flag if the user pressed
@@ -662,23 +675,168 @@
      as an event.  The normal check for quit will discard the C-g,
      which would be bad.
 
-     #### C-g is still often read as quit, e.g. if you type C-x C-g
-     (the C-g happens during the sit-for in maybe_echo_keys(); even
-     if we attempt to inhibit quit here, there is still a check
-     later on for QUIT.  To fix this properly requires a fairly
-     substantial overhaul of the quit-checking code, which is
-     probably not worth it.)
+     [[#### C-g is still often read as quit, e.g. if you type C-x C-g (the
+     C-g happens during the sit-for in maybe_echo_keys(); even if we
+     attempt to inhibit quit here, there is still a check later on for
+     QUIT.  To fix this properly requires a fairly substantial overhaul of
+     the quit-checking code, which is probably not worth it.)]] not true,
+     we just have to always do dont_check_for_quit around all code that
+     reads events.  my stderr-proc ws already does this.
 
      We should *not* conditionalize on Vinhibit_quit, or
      critical-quit (Control-Shift-G) won't work right. */
 
+  /* WARNING: Even calling check_quit(), without actually dispatching
+     a quit signal, can result in arbitrary Lisp code getting executed
+     -- at least under Windows. (Not to mention obvious Lisp
+     invocations like asynchronous timer callbacks.) Here's a sample
+     stack trace to demonstrate:
+
+ NTDLL! DbgBreakPoint@0 address 0x77f9eea9
+assert_failed(const char * 0x012d036c, int 4596, const char * 0x012d0354) line 3478
+re_match_2_internal(re_pattern_buffer * 0x012d6780, const unsigned char * 0x00000000, int 0, const unsigned char * 0x022f9328, int 34, int 0, re_registers * 0x012d53d0 search_regs, int 34) line 4596 + 41 bytes
+re_search_2(re_pattern_buffer * 0x012d6780, const char * 0x00000000, int 0, const char * 0x022f9328, int 34, int 0, int 34, re_registers * 0x012d53d0 search_regs, int 34) line 4269 + 37 bytes
+re_search(re_pattern_buffer * 0x012d6780, const char * 0x022f9328, int 34, int 0, int 34, re_registers * 0x012d53d0 search_regs) line 4031 + 37 bytes
+string_match_1(long 31222628, long 30282164, long 28377092, buffer * 0x022fde00, int 0) line 413 + 69 bytes
+Fstring_match(long 31222628, long 30282164, long 28377092, long 28377092) line 436 + 34 bytes
+Ffuncall(int 3, long * 0x008297f8) line 3488 + 168 bytes
+execute_optimized_program(const unsigned char * 0x020ddc50, int 6, long * 0x020ddf50) line 744 + 16 bytes
+funcall_compiled_function(long 34407748, int 1, long * 0x00829aec) line 516 + 53 bytes
+Ffuncall(int 2, long * 0x00829ae8) line 3523 + 17 bytes
+execute_optimized_program(const unsigned char * 0x020ddc90, int 4, long * 0x020ddf90) line 744 + 16 bytes
+funcall_compiled_function(long 34407720, int 1, long * 0x00829e28) line 516 + 53 bytes
+Ffuncall(int 2, long * 0x00829e24) line 3523 + 17 bytes
+mapcar1(long 15, long * 0x00829e48, long 34447820, long 34187868) line 2929 + 11 bytes
+Fmapcar(long 34447820, long 34187868) line 3035 + 21 bytes
+Ffuncall(int 3, long * 0x00829f20) line 3488 + 93 bytes
+execute_optimized_program(const unsigned char * 0x020c2b70, int 7, long * 0x020dd010) line 744 + 16 bytes
+funcall_compiled_function(long 34407580, int 2, long * 0x0082a210) line 516 + 53 bytes
+Ffuncall(int 3, long * 0x0082a20c) line 3523 + 17 bytes
+execute_optimized_program(const unsigned char * 0x020cf810, int 6, long * 0x020cfb10) line 744 + 16 bytes
+funcall_compiled_function(long 34407524, int 0, long * 0x0082a580) line 516 + 53 bytes
+Ffuncall(int 1, long * 0x0082a57c) line 3523 + 17 bytes
+run_hook_with_args_in_buffer(buffer * 0x022fde00, int 1, long * 0x0082a57c, int 0) line 3980 + 13 bytes
+run_hook_with_args(int 1, long * 0x0082a57c, int 0) line 3993 + 23 bytes
+Frun_hooks(int 1, long * 0x0082a57c) line 3847 + 19 bytes
+run_hook(long 34447484) line 4094 + 11 bytes
+unsafe_handle_wm_initmenu_1(frame * 0x01dbb000) line 736 + 11 bytes
+unsafe_handle_wm_initmenu(long 28377092) line 807 + 11 bytes
+condition_case_1(long 28377116, long (long)* 0x0101c827 unsafe_handle_wm_initmenu(long), long 28377092, long (long, long)* 0x01005fa4 mswindows_modal_loop_error_handler(long, long), long 28377092) line 1692 + 7 bytes
+mswindows_protect_modal_loop(long (long)* 0x0101c827 unsafe_handle_wm_initmenu(long), long 28377092) line 1194 + 32 bytes
+mswindows_handle_wm_initmenu(HMENU__ * 0x00010199, frame * 0x01dbb000) line 826 + 17 bytes
+mswindows_wnd_proc(HWND__ * 0x000501da, unsigned int 278, unsigned int 65945, long 0) line 3089 + 31 bytes
+USER32! UserCallWinProc@20 + 24 bytes
+USER32! DispatchClientMessage@20 + 47 bytes
+USER32! __fnDWORD@4 + 34 bytes
+NTDLL! KiUserCallbackDispatcher@12 + 19 bytes
+USER32! DispatchClientMessage@20 address 0x77e163cc
+USER32! DefWindowProcW@16 + 34 bytes
+qxeDefWindowProc(HWND__ * 0x000501da, unsigned int 274, unsigned int 61696, long 98) line 1188 + 22 bytes
+mswindows_wnd_proc(HWND__ * 0x000501da, unsigned int 274, unsigned int 61696, long 98) line 3362 + 21 bytes
+USER32! UserCallWinProc@20 + 24 bytes
+USER32! DispatchClientMessage@20 + 47 bytes
+USER32! __fnDWORD@4 + 34 bytes
+NTDLL! KiUserCallbackDispatcher@12 + 19 bytes
+USER32! DispatchClientMessage@20 address 0x77e163cc
+USER32! DefWindowProcW@16 + 34 bytes
+qxeDefWindowProc(HWND__ * 0x000501da, unsigned int 262, unsigned int 98, long 540016641) line 1188 + 22 bytes
+mswindows_wnd_proc(HWND__ * 0x000501da, unsigned int 262, unsigned int 98, long 540016641) line 3362 + 21 bytes
+USER32! UserCallWinProc@20 + 24 bytes
+USER32! DispatchMessageWorker@8 + 244 bytes
+USER32! DispatchMessageW@4 + 11 bytes
+qxeDispatchMessage(const tagMSG * 0x0082c684 {msg=0x00000106 wp=0x00000062 lp=0x20300001}) line 989 + 10 bytes
+mswindows_drain_windows_queue() line 1345 + 9 bytes
+emacs_mswindows_quit_p() line 3947
+event_stream_quit_p() line 666
+check_quit() line 686
+check_what_happened() line 437
+re_match_2_internal(re_pattern_buffer * 0x012d5a18, const unsigned char * 0x00000000, int 0, const unsigned char * 0x02235000, int 23486, int 14645, re_registers * 0x012d53d0 search_regs, int 23486) line 4717 + 14 bytes
+re_search_2(re_pattern_buffer * 0x012d5a18, const char * 0x02235000, int 23486, const char * 0x0223b38e, int 0, int 14645, int 8841, re_registers * 0x012d53d0 search_regs, int 23486) line 4269 + 37 bytes
+search_buffer(buffer * 0x022fde00, long 29077572, long 13789, long 23487, long 1, int 1, long 28377092, long 28377092, int 0) line 1224 + 89 bytes
+search_command(long 29077572, long 46975, long 28377116, long 28377092, long 28377092, int 1, int 1, int 0) line 1054 + 151 bytes
+Fre_search_forward(long 29077572, long 46975, long 28377116, long 28377092, long 28377092) line 2147 + 31 bytes
+Ffuncall(int 4, long * 0x0082ceb0) line 3488 + 216 bytes
+execute_optimized_program(const unsigned char * 0x02047810, int 13, long * 0x02080c10) line 744 + 16 bytes
+funcall_compiled_function(long 34187208, int 3, long * 0x0082d1b8) line 516 + 53 bytes
+Ffuncall(int 4, long * 0x0082d1b4) line 3523 + 17 bytes
+execute_optimized_program(const unsigned char * 0x01e96a10, int 6, long * 0x020ae510) line 744 + 16 bytes
+funcall_compiled_function(long 34186676, int 3, long * 0x0082d4a0) line 516 + 53 bytes
+Ffuncall(int 4, long * 0x0082d49c) line 3523 + 17 bytes
+execute_optimized_program(const unsigned char * 0x02156b50, int 4, long * 0x020c2db0) line 744 + 16 bytes
+funcall_compiled_function(long 34186564, int 2, long * 0x0082d780) line 516 + 53 bytes
+Ffuncall(int 3, long * 0x0082d77c) line 3523 + 17 bytes
+execute_optimized_program(const unsigned char * 0x0082d964, int 3, long * 0x020c2d70) line 744 + 16 bytes
+Fbyte_code(long 29405156, long 34352480, long 7) line 2392 + 38 bytes
+Feval(long 34354440) line 3290 + 187 bytes
+condition_case_1(long 34354572, long (long)* 0x01087232 Feval(long), long 34354440, long (long, long)* 0x01084764 run_condition_case_handlers(long, long), long 28377092) line 1692 + 7 bytes
+condition_case_3(long 34354440, long 28377092, long 34354572) line 1779 + 27 bytes
+execute_rare_opcode(long * 0x0082dc7c, const unsigned char * 0x01b090af, int 143) line 1269 + 19 bytes
+execute_optimized_program(const unsigned char * 0x01b09090, int 6, long * 0x020ae590) line 654 + 17 bytes
+funcall_compiled_function(long 34186620, int 0, long * 0x0082df68) line 516 + 53 bytes
+Ffuncall(int 1, long * 0x0082df64) line 3523 + 17 bytes
+execute_optimized_program(const unsigned char * 0x02195470, int 1, long * 0x020c2df0) line 744 + 16 bytes
+funcall_compiled_function(long 34186508, int 0, long * 0x0082e23c) line 516 + 53 bytes
+Ffuncall(int 1, long * 0x0082e238) line 3523 + 17 bytes
+execute_optimized_program(const unsigned char * 0x01e5d410, int 6, long * 0x0207d410) line 744 + 16 bytes
+funcall_compiled_function(long 34186312, int 1, long * 0x0082e524) line 516 + 53 bytes
+Ffuncall(int 2, long * 0x0082e520) line 3523 + 17 bytes
+execute_optimized_program(const unsigned char * 0x02108fb0, int 2, long * 0x020c2e30) line 744 + 16 bytes
+funcall_compiled_function(long 34186340, int 0, long * 0x0082e7fc) line 516 + 53 bytes
+Ffuncall(int 1, long * 0x0082e7f8) line 3523 + 17 bytes
+execute_optimized_program(const unsigned char * 0x020fe150, int 2, long * 0x01e6f510) line 744 + 16 bytes
+funcall_compiled_function(long 31008124, int 0, long * 0x0082ebd8) line 516 + 53 bytes
+Ffuncall(int 1, long * 0x0082ebd4) line 3523 + 17 bytes
+run_hook_with_args_in_buffer(buffer * 0x022fde00, int 1, long * 0x0082ebd4, int 0) line 3980 + 13 bytes
+run_hook_with_args(int 1, long * 0x0082ebd4, int 0) line 3993 + 23 bytes
+Frun_hooks(int 1, long * 0x0082ebd4) line 3847 + 19 bytes
+Ffuncall(int 2, long * 0x0082ebd0) line 3509 + 14 bytes
+execute_optimized_program(const unsigned char * 0x01ef2210, int 5, long * 0x01da8e10) line 744 + 16 bytes
+funcall_compiled_function(long 31020440, int 2, long * 0x0082eeb8) line 516 + 53 bytes
+Ffuncall(int 3, long * 0x0082eeb4) line 3523 + 17 bytes
+execute_optimized_program(const unsigned char * 0x0082f09c, int 3, long * 0x01d89390) line 744 + 16 bytes
+Fbyte_code(long 31102388, long 30970752, long 7) line 2392 + 38 bytes
+Feval(long 31087568) line 3290 + 187 bytes
+condition_case_1(long 30961240, long (long)* 0x01087232 Feval(long), long 31087568, long (long, long)* 0x01084764 run_condition_case_handlers(long, long), long 28510180) line 1692 + 7 bytes
+condition_case_3(long 31087568, long 28510180, long 30961240) line 1779 + 27 bytes
+execute_rare_opcode(long * 0x0082f450, const unsigned char * 0x01ef23ec, int 143) line 1269 + 19 bytes
+execute_optimized_program(const unsigned char * 0x01ef2310, int 6, long * 0x01da8f10) line 654 + 17 bytes
+funcall_compiled_function(long 31020412, int 1, long * 0x0082f740) line 516 + 53 bytes
+Ffuncall(int 2, long * 0x0082f73c) line 3523 + 17 bytes
+execute_optimized_program(const unsigned char * 0x020fe650, int 3, long * 0x01d8c490) line 744 + 16 bytes
+funcall_compiled_function(long 31020020, int 2, long * 0x0082fa14) line 516 + 53 bytes
+Ffuncall(int 3, long * 0x0082fa10) line 3523 + 17 bytes
+Fcall_interactively(long 29685180, long 28377092, long 28377092) line 1008 + 22 bytes
+Fcommand_execute(long 29685180, long 28377092, long 28377092) line 2929 + 17 bytes
+execute_command_event(command_builder * 0x01be1900, long 36626492) line 4048 + 25 bytes
+Fdispatch_event(long 36626492) line 4341 + 70 bytes
+Fcommand_loop_1() line 582 + 9 bytes
+command_loop_1(long 28377092) line 495
+condition_case_1(long 28377188, long (long)* 0x01064fb9 command_loop_1(long), long 28377092, long (long, long)* 0x010649d0 cmd_error(long, long), long 28377092) line 1692 + 7 bytes
+command_loop_3() line 256 + 35 bytes
+command_loop_2(long 28377092) line 269
+internal_catch(long 28457612, long (long)* 0x01064b20 command_loop_2(long), long 28377092, int * volatile 0x00000000) line 1317 + 7 bytes
+initial_command_loop(long 28377092) line 305 + 25 bytes
+STACK_TRACE_EYE_CATCHER(int 1, char * * 0x01b63ff0, char * * 0x01ca5300, int 0) line 2501
+main(int 1, char * * 0x01b63ff0, char * * 0x01ca5300) line 2938
+XEMACS! mainCRTStartup + 180 bytes
+_start() line 171
+KERNEL32! BaseProcessStart@4 + 115547 bytes
+
+*/
+
   if (dont_check_for_quit)
     return 0;
 
   if (quit_check_signal_happened)
     {
+      /* Since arbitrary Lisp code may be executed, GC might happen,
+         which would majorly fuck a lot of things, e.g. re_match()
+         [string gets relocated] and lots of other code that's not
+         prepared to handle GC in QUIT. */
+      int specdepth = begin_gc_forbidden ();
       quit_check_signal_happened = 0;
       event_stream_quit_p ();
+      unbind_to (specdepth);
       return 1;
     }
   else