On 11/06/2012 03:43, Simon Urbanek wrote:
> On Jun 10, 2012, at 9:24 PM, Dirk Eddelbuettel wrote:
>
>> On 8 June 2012 at 12:27, Renaud Gaujoux wrote:
>> | PS: Dirk do you want me to post this on the Rcpp list for record?
>>
>> Yes, that generally is where Rcpp questions / comments / hints should go.
>>
>> As for multi-arch builds, I am not sure we even thought about supporting this so if
>> it breaks your use of Rcpp and related packages, you get to keep the pieces.
>> That said, I'd be interested in supporting it eventually but I guess I want
>> to first understand better how/if it is supported (on Linux) by R itself.
>>
> R itself of course supports it and essentially all packages (including Rcpp ;)) have to because we require it on Windows and OS X since all binaries there are multi-lib.
 From what I understood fro R-Writing extensions, multi-arch support 
would generally be about following the following recommendation:

"If you want to run R code inMakevars, e.g. to find configuration 
information, please do ensure that you use the correct copy 
of|R|or|Rscript|: there might not be one in the path at all, or it might 
be the wrong version or architecture. The correct way to do this is/via/

      "$(R_HOME)/bin$(R_ARCH_BIN)/Rscript"filename
      "$(R_HOME)/bin$(R_ARCH_BIN)/Rscript" -e 'R expression'

where|$(R_ARCH_BIN)|is only needed currently on Windows."


So unless different external libraries are required for the different 
types build (32 or 64 bits), there should be nothing special to do to 
ensure support of multi-arch.
In particular, on Linux, "$(R_HOME)/bin/Rscript" -e 'R expression'" 
should work in both single and multi-arch setup, correct?

> As far as R is concerned it works equally well on Linux - the problem there is more on the side of distributions, because it is more unusual to have multi-lib Linux (originally it was used on Linux only to get 3rd party [mostly proprietary] 32-bit binaries working on 64-bit systems and that is now less of an issue). As I said in the original post it works reasonably well on Debian (not for all libraries since only a subset is available, but all the basic ones) -- there were shakeups in Ubuntu which were messing with the multilib support, so I don't know the current status but I can check at work tomorrow (probably not for something as ancient as natty, though).
I think you are right Simon: the issue likely comes from my Linux 
distrib, which I effectively should upgrade. This gives me one more 
reason to do it asap.
If you have some -- even untested -- clues on how to get things working 
on Natty I am happy to test them though, as upgrades always have hidden 
issues and time black holes...
Thank you.

Bests,
Renaud

>
> Cheers,
> Simon
>
>
>> -- 
>> Dirk Eddelbuettel | edd@debian.org | http://dirk.eddelbuettel.com
>>
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