[Rd] a plead to package developers regarding GCC

[Liaw, Andy]

Dear DevelopeRs,

I'd like to ask those who develop R packages with compiled code to please
try avoiding dependency on GCC (gcc/g77/gfortran/g++) specific features in
the code, for the simple reason that there are non-GCC compilers out there
that might choke on such features.

I found this out back when I was trying to build R-2.3.0-to-be on our dual
Opteron based Scyld cluster.  Because the GCC that shipped with the current
Scyld is too old for building R properly on that architecture, we ended up
using the Portland Group compilers (PGI 6.1).  After some update in the R
source, I got R to build and pass make check-all.  However, when installing
contributed packages on CRAN, quite a few failed.  I manually checked a
handful, and found that some of the code defined some basic math functions
that conflicts with intrinsics.  Removal of such code enable me to build and
run package checks on them successfully.  I believe many of such cases stem
from the fact that the code were originally from the output of g2c.

I can try to post a more concrete example if needed.  I think resolving this
will facilitate wider use of these packages.

Thanks for your consideration.

Best,
Andy

Andy Liaw, PhD
Biometrics Research    PO Box 2000 RY33-300
Merck Research Labs        Rahway, NJ 07065
andy_liaw(a)merck.com          732-594-0820