[Rd] [R] can't load rJava in R 2.8.1 on Windows XP
murdoch at stats.uwo.ca
Mon Jan 26 14:13:57 CET 2009
On 1/26/2009 7:04 AM, Duncan Murdoch wrote:
> Dieter Menne wrote:
>> Duncan Murdoch <murdoch <at> stats.uwo.ca> writes:
>>> I don't know what's going wrong on your system. I added a browser()
>>> call to the .onLoad function in R/windows/FirstLib.R on my system, and I
>>> see it successfully gets JAVA_HOME from the registry. It gets a number
>>> of other files, then adds these paths to my PATH variable. I've used
>>> strsplit() to separate them for viewing.
>>>  "C:\\Program Files\\Java\\jre1.6.0_07\\bin\\client"
>>>  "C:\\Program Files\\Java\\jre1.6.0_07/bin"
>>>  "C:\\Program Files\\Java\\jre1.6.0_07/bin/client"
>>>  "C:\\Program Files\\Java\\jre1.6.0_07/jre/bin/client"
>>> I believe LoadLibrary needs paths to be specified with backslashes, so
>>> you might be able to fix things on your system by changing the file.path
>>> calls in that function to use fsep="\\" instead of the default "/".
>> Thanks for your help.
>> I think I tracked it down. It has nothing to do with rJava, but
>> rather with Sys.getenv(). Looks like this function truncates around 1024
>> characters, and my path is very long due to Visual Studio + Delphi
>> + SQL Server.
>> See the printout below. Note that the last entry should read \\Delphi,
>> and that more entries are coming in my system path.
>> This also explains why only some people have the problem.
>> No workaround found yet. I keep this message here for other people who
>> have the problem, but possibly this is more for R-devel to be continued.
> Yes, I've moved this to R-devel.
> If this is an R problem, it's in Sys.setenv: putting a very long string
> and then starting a shell shows the truncated string, but within the
> shell it's possible to set a much longer one.
> However, I don't see a fixed buffer size in the internal R code, so this
> looks like a problem in the run-time. The docs on MSDN say that the
> system maintains separate user environment variables and system
> environment variables, and the system ones are limited to 1024
> characters: so this could be our problem. Our _wputenv call may be
> trying to set a system environment variable, and having it truncated.
> (There's also an overall limit of 32767 chars for all environment
> variables, but I'd guess you're hitting the 1024 byte limit.)
> The docs also say there's a SetEnvironmentVariable API function as of
> Win2k, which is our minimal platform these days, so maybe switching to
> that would solve the problem. I'll give it a try, but probably not today.
One more followup: This article
says that this is a problem in Windows XP SP2 and Windows Server 2003,
and provides a fix for those systems.
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