[R-SIG-Mac] OpenMP in R 2.13.1

[Simon Urbanek]

Michael,

On Sep 30, 2011, at 4:04 PM, Michael Spiegel wrote:

> I apologize for cross-posting from R-SIG-hpc, but I realized this
> group is likely to have more mac users than the other group. Can
> someone with a Mac go ahead and check in
> /Library/Frameworks/R.framework/Resources/etc/x86_64/Makeconf and
> confirm that the value for SHLIB_OPENMP_CFLAGS is empty when running R
> 2.13.1 and set to “-fopenmp” when running R 2.13.0? I this is bug, but
> I just want independent confirmation before I report this behavior.
> 

It's not a bug -- the gomp used by Apple's gcc is buggy and crashes when other threads are involved, so it is disabled in the R distribution (this was discovered after the 2.13.0 release). This is just one of many problems in the gomp on OS X, so if you need OpenMP for a particular package, you may be better off testing that it will work in your case and enable it for your build of the package in question using PKG_xx flags.

Cheers,
Simon