[Rcpp-devel] RcppArmadillo build failures

[Dirk Eddelbuettel]

On 27 October 2017 at 08:11, Dirk Eddelbuettel wrote:
| 
| We have two recent build failures reports at GitHub:
| 
| https://github.com/RcppCore/RcppArmadillo/issues/177
| https://github.com/RcppCore/RcppArmadillo/issues/185
| 
| I don't understand what is going on as this just builds fine on my systems.
| We test for a sufficient compiler, use C++11 and expect OpenMP to work.  Yet
| it doesn't.  I don't really know what is missing, and the respective OP
| aren't forthcoming (yet, maybe) with pertinent info.
| 
| Anybody have an idea?

Turns out it was Conrad's code making use of new #Pragma syntax for OpenMP
which remains borked up until g++-5.4, and hence clearly for the still
popular-in-many-places g++-4.9.   For what it is worth many of us now have
g++-6, with g++-7 in Debian and g++-8 just added to the 'experimental'
branch.

But for those with older compilers we now test and accomodate by turning
OpenMP off.  You can use the updated RcppArmadillo via either

  drat::addRepo("RcppCore")             # RcppCore drat repo known for session
  install.packages("RcppArmadillo")

or

  install.packages("RcppArmadillo", repos="https://RcppCore.github.io/drat")

Hope this helps, and thanks to everybody who contributed in sorting this out.

Dirk


-- 
http://dirk.eddelbuettel.com | @eddelbuettel | edd at debian.org