[Rd] cpu usage high with windows change dir / winDialogString (PR#11045)

[seanpor at acm.org]

Good afternoon,

This is possibly a windows only bug, definitely of comparatively low
importance - but for the sake of completeness here we go.  I've
searched http://bugs.R-project.org/ etc., but can find no mention.

For RGui.exe, the CPU usage goes to 100% for certain dialog boxes for
the duration that the dialog box is visible, e.g.

* check CPU usage is low
* On the RGui.exe menu chose File / Change dir...
* the CPU usage goes to 100%
* hit OK
* the CPU usage goes back down again

This also occurs when I incant Help / Apropos or Help / Search help...
or at the "command prompt"

> winDialogString("hello", "nonsense")

Note the latter also applies to R.exe inside a cmd window.

I've checked this with a few windows machines for 2.6.2 & 2.6.1 -
including with --vanilla.  This machine here has the following...
> sessionInfo()
R version 2.6.2 (2008-02-08)
i386-pc-mingw32

locale:
LC_COLLATE=English_Ireland.1252;LC_CTYPE=English_Ireland.1252;LC_MONETARY=English_Ireland.1252;LC_NUMERIC=C;LC_TIME=English_Ireland.1252

attached base packages:
[1] stats     graphics  grDevices utils     datasets  methods   base
> version
               _
platform       i386-pc-mingw32
arch           i386
os             mingw32
system         i386, mingw32
status
major          2
minor          6.2
year           2008
month          02
day            08
svn rev        44383
language       R
version.string R version 2.6.2 (2008-02-08)

I am not familiar with the R sources, so the following should be taken
with a large grain of salt... to my uninitiated eyes it appears to be
something to do with askstring() in src\extra\graphapp\dialogs.c
or possibly handle_message_dialog() - I'm afraid I have never
programmed windows at a low level so I'm not sure what's going on
here...

I am of course available to help pin this down - but unfortunately I
don't have a development environment here.

Best Regards,
Sean O'Riordain
Dublin, Ireland
not affiliated...
seanpor A T acm D ot org