[R-SIG-Mac] building 32-bit version of R 3.x

[Simon Urbanek]

On Mar 3, 2014, at 12:25 AM, Alexy Khrabrov <deliverable at gmail.com> wrote:

> On Tue, Feb 25, 2014 at 3:11 AM, Prof Brian Ripley
> <ripley at stats.ox.ac.uk> wrote:
> 
>>> Looking at the sources, there's no obvious way to switch to 32-bit.  The
>>> gfortran.pkg (4.2.3) seems obsolete; I've configured the default setup
>> 
>> So?  At least it includes a 32-bit compiler (by default if I understand the
>> version you are using).
>> 
> 
> Correct -- but with the current Apple gcc and -arch i386, that old gfortran and C++ disagree on integer and double sizes in configure.
> 

I don't think so - those two the same even between 32-bit and 64-bit. I suspect you're misinterpreting the output (which you didn't provide) and if there is indeed some other error you have likely not set the correct flags. I can confirm that

CC='gcc -arch i386' CXX='g++ -arch i386' F77='gfortran -arch i386' FC='gfortran -arch i386' OBJC='gcc -arch i386'

works just fine (assuming your system has both 32-bit and 64-bit libraries).


>> You need to specify a 32-bit compiler.  AFAIK -arch is specific to Apple
>> front-ends, and the value is i386, not x686.
>> 
>> If you build multilib GCC from the sources, the flag needed is -m32.
>> 
>> This *is* all in the relevant manual.
> 
> The manual seems rather general there.  I'd like to know whether
> someone has done this recently and what the exact steps are to
> 
> -- build the gcc and gfortran with both i386 and x86_64 standard libraries
> -- compile latest R with it
> -- how to install and manage the setup for invoking one or the other,
> and linking to one's or the other's .dylib
> 

You cannot link one another's dylibs since they are two entirely different, incompatible architectures.

Building R with the default compilers (Apple + gfortran from CRAN) works out of the box for both in 32-bit and 64-bit. For any other setup, you're entirely on your own. If you want a multi-arch installation of R, you can set r_arch=i386 for the 32-bit build and r_arch=x86_64 for the 64-bin build to build separate architectures. The default install will then create a merged universal framework - see instructions for 2.x series of R that used multi-arch install on OS X. 


>>>        [[alternative HTML version deleted]]
> 
> I'll dare to object to your signature objection here -- the times
> moved on, and most web-based email services, such as gmail, use HTML
> mail by default.  Even those who used to run mutt and the like are on
> gmail, and not always do they bother to set plain text mode.  So I'd
> be OK with the line above, but I will set plain text mode to honor the
> tradition.
> 

As David pointed out you can object all you want, but those are the rules you were asked to abide by. Whether you like them or not is relevant - HTML cause unnecessary problems in e-mails. Unfortunately, bad defaults are ubiquitous (just look at Outlook to see how you can end up with e-mails that have content that doesn't communicate anything - not even the intended message). 

Cheers,
Simon