[Rd] Rgui.exe plot device "Save as" crash (PR#9237)

mwtoews at sfu.ca mwtoews at sfu.ca
Tue Sep 19 20:16:26 CEST 2006

I was guessing that this bug would be difficult to trace, I just wanted 
to document its presence. It is not critical, and can be easily be 
avoided by:
- Saving in Jpeg format; or
- Not saving to the Desktop (unless navigated from C:\Documents and 

I'm not convinced that this bug is related to Adobe (as mentioned in 
Followup 1) .. my example uses PDF, but the same bug occurs when using 
Png, and others (except Jpeg!?).
> I really don't know where to go to start looking for this.  It would be
> nice if we had something like valgrind for Windows, but we don't.
Regarding valgrind (or other memory debuggers): I'm not a Windows 
programmer, but would WinDbg be helpful for debugging this? I tried this 
(free download from MS), and it shows plenty of debugging info, such as 
values of registers, and the sequences of assembly operators on the CPU, 
etc. When I open Rgui.exe, it shows all sorts of modules loading when 
the "Save as" dialog appears, and when Tooltips are triggered; such as: 
PDFShell.dll (from Acrobat 7.0), esriShellExt.dll (from ArcGIS), and 
various *.so files from TortoiseSVN\iconv. The crash occurs, and WinDbg 

(934.ba8): Access violation - code c0000005 (first chance)
First chance exceptions are reported before any exception handling.
This exception may be expected and handled.
eax=049c2038 ebx=00000000 ecx=0486f1d4 edx=0486f1cc esi=0486f3e0 
eip=7ca5158e esp=0486f134 ebp=0486f37c iopl=0         nv up ei pl zr na 
pe nc
cs=001b  ss=0023  ds=0023  es=0023  fs=003b  gs=0000             
*** ERROR: Symbol file could not be found.  Defaulted to export symbols 
for C:\WINDOWS\system32\SHELL32.dll -
7ca5158e 8b08            mov     ecx,dword ptr [eax]  

and when I press "Go" in WinDbg, the instruction/error repeats ad 
nauseam (with the 'efl' register flipping between 00000246 and 00010246; 
hence the infinite loop).

I didn't load the "symbols file" (I'm not sure what this is -- WinDbg is 
new territory for me today), but I would guess this could make the 
debugging output more meaningful. My first impression of WinDbg is that 
it can be useful for this situation (and others).

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