R --debug crashes R on Windows

I really meant crash and left my report short thinking others would be
able to reproduce this immediately.  Details:

* Launching 'Rterm --debug' from the Windows Command prompt gives me a
"R for Windows terminal front-end has stopped working: A problem
caused the ... [Close program]" dialog without any kind of output from
R itself.
* It happens with both 'i386\Rterm.exe --debug' and 'x64\Rterm.exe --debug'
* When doing 'Rgui.exe --debug', there is no message (nor an error
message/dialog) and it exits immediately.
(* Trying random non-existing command line options (with R, Rterm and
Rgui) are properly ignored and gives a warning, e.g. WARNING: unknown
option '--dror' when launching R.)
* It happens with R v2.10.0, R v2.14.2, R v2.15.0patched, and R devel
(binaries from CRAN).   On R v2.13.0, it *hangs* (!=exit) without the
dialog and it responds to Ctrl-C.
* Trying to use WinDbg, I get the following from the core dump:

Microsoft (R) Windows Debugger Version 6.12.0002.633 AMD64
Copyright (c) Microsoft Corporation. All rights reserved.

Loading Dump File [C:\Users\hb\AppData\Local\CrashDumps\Rterm.exe.6212.dmp]
User Mini Dump File: Only registers, stack and portions of memory are available

Symbol search path is:
SRV*C:\SymCache*http://msdl.microsoft.com/download/symbols
Executable search path is:
Windows 7 Version 7601 (Service Pack 1) MP (4 procs) Free x64
Product: WinNt, suite: SingleUserTS
Machine Name:
Debug session time: Tue Apr 17 11:50:48.000 2012 (UTC - 7:00)
System Uptime: not available
Process Uptime: 0 days 0:00:16.000
............................
This dump file has a breakpoint exception stored in it.
The stored exception information can be accessed via .ecxr.
ntdll!ZwWaitForMultipleObjects+0xa:
00000000`77a618ca c3              ret

I don't find this particularly important, but wanted to share in case
there is some deprecated.obsolete code in there for option '--debug'.

From your reply it sounds as if --debug is intended, so ok with me.

/Henrik

On Tue, Apr 17, 2012 at 3:43 AM, Duncan Murdoch
<murdoch.duncan at gmail.com>  wrote:

On 12-04-17 2:19 AM, Henrik Bengtsson wrote:

'R --debug' and 'Rterm --debug' crash R on Windows.  Indeed, --debug
is not a documented command line option, but it still causes a crash.

This occurs with R v2.15.0 patched and R devel - both from 2012-04-09
(r58947).

What do you mean by "crash"?  For me, they do nothing, i.e. both commands
just exit immediately.  What the source shows they are trying to do is break
to a debugger upon startup, but if there's no debugger there, it might look
like a crash.

Duncan Murdoch