force-mode-line-update [Re: Is this correct?]

[Uday S Reddy]

[Following up on a discussion in the gnu.emacs.help newsgroup.]

On 2/26/2011 4:59 PM, Eli Zaretskii wrote:

> > You are saying that it works fine otherwise?
>
> I'm asking _you_ if it does.

Right, I suppose I asked for it :-(

I tested similar code to force-mode-line-update by using a different 
buffer than "other-buffer".

         (when (and vm-user-interaction-buffer
                    (buffer-live-p vm-user-interaction-buffer))
           (with-current-buffer vm-user-interaction-buffer))
         (set-buffer-modified-p (buffer-modified-p))

vm-user-interaction-buffer is the active buffer where the user issued a 
command to change the menubar.  And, the buffer where this code got 
executed is an invisible Folder buffer.

It didn't work, i.e., the menubar didn't get updated.  I needed to click 
for a second time somewhere in the menubar for it to get updated.  And, 
after trying it a few times Emacs crashed with the message

  The instruction at "0x7c911766" referenced memory at "0x0084fffd". 
The memory could not be read.

This is using the current pretest, Sean Sieger's build.  The DrMinGW 
backtrace is below.

I could not reproduce this crash on Emacs 23.2.1.  However, doing this 
seems to have put it in an unstable state.  Doing something else 
afterwards crashed it.  I am also attaching the report from DrMinGW for 
that crash.

Cheers,
Uday
-----------
Crash backtrace for 23.2.94

emacs.exe caused an Access Violation at location 7c911766 in module 
ntdll.dll Reading from location 00690070.

Registers:
eax=00850190 ebx=00850000 ecx=7ffde000 edx=00850608 esi=0069006b 
edi=00000003
eip=7c911766 esp=0082e408 ebp=0082e628 iopl=0         nv up ei pl nz ac 
pe nc
cs=001b  ss=0023  ds=0023  es=0023  fs=003b  gs=0000 
efl=00000212

Call stack:
7C911766  ntdll.dll:7C911766  RtlInitializeCriticalSection
011CDFAE  emacs.exe:011CDFAE  add_menu_item  w32menu.c:1494

011CE25B  emacs.exe:011CE25B  fill_in_menu  w32menu.c:1592

011CE20B  emacs.exe:011CE20B  fill_in_menu  w32menu.c:1583

011CCD03  emacs.exe:011CCD03  set_frame_menubar  w32menu.c:626

011CC397  emacs.exe:011CC397  x_activate_menubar  w32menu.c:285

0100B56D  emacs.exe:0100B56D  kbd_buffer_get_event  keyboard.c:4419

010094BA  emacs.exe:010094BA  read_char  keyboard.c:3081

0101292D  emacs.exe:0101292D  read_key_sequence  keyboard.c:9567

010065C5  emacs.exe:010065C5  command_loop_1  keyboard.c:1645

01020614  emacs.exe:01020614  internal_condition_case  eval.c:1492

01005FE3  emacs.exe:01005FE3  command_loop_2  keyboard.c:1362

01020165  emacs.exe:01020165  internal_catch  eval.c:1228

01005F49  emacs.exe:01005F49  command_loop  keyboard.c:1327

0100588E  emacs.exe:0100588E  recursive_edit_1  keyboard.c:956

010EC664  emacs.exe:010EC664  read_minibuf  minibuf.c:744

010EE2C6  emacs.exe:010EE2C6  Fcompleting_read  minibuf.c:1827

01014F1E  emacs.exe:01014F1E  Fexecute_extended_command  keyboard.c:10622

01022AE3  emacs.exe:01022AE3  Ffuncall  eval.c:3031

0111932A  emacs.exe:0111932A  Fcall_interactively  callint.c:869

01022B2E  emacs.exe:01022B2E  Ffuncall  eval.c:3037

010226CC  emacs.exe:010226CC  call3  eval.c:2857

01014D52  emacs.exe:01014D52  Fcommand_execute  keyboard.c:10562

010076E0  emacs.exe:010076E0  command_loop_1  keyboard.c:1914

01020614  emacs.exe:01020614  internal_condition_case  eval.c:1492

01005FE3  emacs.exe:01005FE3  command_loop_2  keyboard.c:1362

01020165  emacs.exe:01020165  internal_catch  eval.c:1228

01005F9C  emacs.exe:01005F9C  command_loop  keyboard.c:1342

0100588E  emacs.exe:0100588E  recursive_edit_1  keyboard.c:956

010059F7  emacs.exe:010059F7  Frecursive_edit  keyboard.c:1019

010028F5  emacs.exe:010028F5  main  emacs.c:1835

010010DB  emacs.exe:010010DB
01001178  emacs.exe:01001178
010036D0  emacs.exe:010036D0  _start  unexw32.c:131

7C817077  kernel32.dll:7C817077  RegisterWaitForInputIdle

-----------

Crash report for Emacs 23.2.1

emacs.exe caused an Access Violation at location 71b225b9 in module 
MPR.DLL Reading from location 5a287ce4.

Registers:
eax=00000000 ebx=00000001 ecx=5a287cb0 edx=00000000 esi=00000000 
edi=0082d80c
eip=71b225b9 esp=0082d7e8 ebp=0082d7f4 iopl=0         nv up ei pl nz na 
pe nc
cs=001b  ss=0023  ds=0023  es=0023  fs=003b  gs=0000 
efl=00000202

Call stack:
71B225B9  MPR.DLL:71B225B9  WNetGetConnectionW
71B223FB  MPR.DLL:71B223FB  WNetGetConnectionW
71B2431D  MPR.DLL:71B2431D  WNetCloseEnum
71B22348  MPR.DLL:71B22348  WNetGetConnectionW
71B222FD  MPR.DLL:71B222FD  WNetGetConnectionW
71B24505  MPR.DLL:71B24505  WNetUseConnectionW
71B24B51  MPR.DLL:71B24B51  WNetUseConnectionA
71B24AE0  MPR.DLL:71B24AE0  WNetAddConnection2A
01094A38  emacs.exe:01094A38
01095E76  emacs.exe:01095E76
0107349C  emacs.exe:0107349C
010734FE  emacs.exe:010734FE
010234B3  emacs.exe:010234B3
0116966B  emacs.exe:0116966B
010225E2  emacs.exe:010225E2
01020ECA  emacs.exe:01020ECA
0116A003  emacs.exe:0116A003
01023BF1  emacs.exe:01023BF1
010236D0  emacs.exe:010236D0
0116966B  emacs.exe:0116966B
01023BF1  emacs.exe:01023BF1
010236D0  emacs.exe:010236D0
0116966B  emacs.exe:0116966B
01023BF1  emacs.exe:01023BF1
010236D0  emacs.exe:010236D0
0116966B  emacs.exe:0116966B
01023BF1  emacs.exe:01023BF1
010236D0  emacs.exe:010236D0
0116966B  emacs.exe:0116966B
01023BF1  emacs.exe:01023BF1
010238DC  emacs.exe:010238DC
010227AE  emacs.exe:010227AE
0101F7D3  emacs.exe:0101F7D3
010223B2  emacs.exe:010223B2
0101F665  emacs.exe:0101F665
010223B2  emacs.exe:010223B2
0101F665  emacs.exe:0101F665
0102076E  emacs.exe:0102076E
010223B2  emacs.exe:010223B2
0101F665  emacs.exe:0101F665
01023BA5  emacs.exe:01023BA5
01023767  emacs.exe:01023767
01022F93  emacs.exe:01022F93
011672D7  emacs.exe:011672D7
01023507  emacs.exe:01023507
0102309F  emacs.exe:0102309F
01014F3A  emacs.exe:01014F3A
0100787F  emacs.exe:0100787F
01020FD4  emacs.exe:01020FD4
01005F66  emacs.exe:01005F66
01020AC5  emacs.exe:01020AC5
01005F1C  emacs.exe:01005F1C
0100580E  emacs.exe:0100580E
01005972  emacs.exe:01005972
010027C6  emacs.exe:010027C6
010010B6  emacs.exe:010010B6
01001148  emacs.exe:01001148
010036EB  emacs.exe:010036EB
7C817077  kernel32.dll:7C817077  RegisterWaitForInputIdle