[Rcpp-devel] RcppEigen-related compilation error for Windows i386

[Dirk Eddelbuettel]

Hi Evan,

On 19 September 2020 at 10:14, Evan Biederstedt wrote:
| I'm in the process uploading an R package to CRAN, which is a relatively
| simple interface to a C++ library: https://github.com/kharchenkolab/N2R
| 
| The windows binaries just became available for RcppSpdLog, so I wanted to
| check how it installed on windows before CRAN submission.
| 
| The package currently installs on Linux and Mac OS, but when I check with
| `devtools::check_win_devel()`, I'm getting a Windows-related error.
| 
| The error appears to be related to RcppEigen, not the C++ library---this
| feels like something easily fixable, but I'm a bit nonplussed how to fix
| this:
| 
| """
| 
| d:/RCompile/CRANpkg/lib/4.1/RcppEigen/include/Eigen/src/Core/DenseCoeffsBase.h:650:34:
| warning: ignoring attributes on template argument
| 'Eigen::internal::packet_traits<int>::type' {aka '__vector(2) long
| long int'} [-Wignored-attributes]
|
|    return internal::first_aligned<int(unpacket_traits<DefaultPacketType>::alignment),Derived>(m);
| 
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
| make: *** [D:/RCompile/recent/R/etc/i386/Makeconf:244: n2knn.o] Error 1
| ERROR: compilation failed for package 'N2R'
| * removing 'd:/RCompile/CRANguest/R-devel/lib/N2R'
| * restoring previous 'd:/RCompile/CRANguest/R-devel/lib/N2R'
| 
| """
| 
| "'Eigen::internal::packet_traits<int>::type' {aka '__vector(2) long long
| int'} [-Wignored-attributes]" appears to be a somewhat standard warning,

Right. Eigen is very verbose. For my local compilations I often set something
like this in ~/.R/Makevars (uncommented, of course, and later in the file
used in CXX*FLAGS):

  #PEDANTIC=-pedantic -DBOOST_NO_AUTO_PTR -Wno-ignored-attributes
  #PEDANTIC= -DBOOST_NO_AUTO_PTR -Wno-sign-compare -Wno-parentheses -Wno-maybe-uninitialized


| but I'm not sure how to resolve
| "internal::first_aligned<int(unpacket_traits<DefaultPacketType>::alignment),Derived>(m);"
| which is causing the compilation error.

That is worse. It seems to rely on 64bit layout. Yet is uses 'int' as opposed
to 'int64_t' which would hardwire the size.

Is the 'int' under your control?  Can you make that an int64_t?

I don't have any other suggestions. :-/

Dirk

| I've tried with C++11 and C++14; same result. I've seen some discussion
| elsewhere that this could be related to the -fopenmp flags here:
| https://github.com/kharchenkolab/N2R/blob/master/src/n2/Makefile
| Perhaps there's something here which clashes with RcppEigen on windows?
| 
| Any help is appreciated. Here is the CRAN builds:
| https://win-builder.r-project.org/D98h1Y2Rr004/
| 
| Best, Evan
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-- 
https://dirk.eddelbuettel.com | @eddelbuettel | edd at debian.org