Rcpp C++11 .Call issues under Windows - regex

Question

I'm experiencing .Call issues when running functions built with Rcpp on Windows, if my c++ code uses C++11 std::regex and I have found no way out so far.
Unlike prior questions on similar issues, I have had neither building nor linking issues. The Rcpp package builds and links fine using the C++11 plugin, making usable packages on my platform. constexpr and C++11-specific functions like std::stoi cause no issue when std::regex is not used.
Using Windows boost libs, I experienced linking issues, even when specifying PKG_LIBS="-L/path/to/boost/libs -lboost_regex", so I'd rather stick to std::regex.
The same packages build, install and run fine under linux, using vanilla std::regex or boost::regex.
I unfortunately found no solution in the fine Rcpp gallery examples.
Windows platform is :
R version 3.2.3 (2015-12-10)
x86_64-w64-mingw32/x64 (64-bit)
Running under:
Windows >= 8 x64 (build 9200)
Rcpp_0.12.3
Rtools 3.3.0.1959 running g++ 4.9.3 (x86_64-posix-seh,
built by MinGW-W64 project), normally C++11-compatible.
PKG_CXXFLAGS="-std=c++11"
The linux platform is similar except for g++ (version 5.3).
Below is a simplified code chunk for duplication.
#include <Rcpp.h>
#if defined(__linux__) && ! defined(FORCE_STL_BUILD)
#include <boost/regex.hpp>
#define reglib boost
#else
#include <regex>
#define reglib std
#endif
#include <string>
using namespace Rcpp;
// [[Rcpp::plugins(cpp11)]]
constexpr int a[3]= {2, 10, 15};
// [[Rcpp::export]]
int my_test(int prop, const std::string& index)
{
#ifndef NO_REG
static const reglib::regex test {"H.*A", reglib::regex::icase};
#endif
int index_int = std::stoi(index) + a[1] + prop;
return index_int;
}
This code runs OK when built using -DNO_REG. Otherwise invoking test::my_test(1, "1000") returns:
`Error in .Call("test_my_test", PACKAGE = "test", prop, index) :
"test_my_test" not available for .Call() for package "test"`
EDIT:
1. The question focuses on std::regex. Boost issues are only incidental comments.
2. Issues only arise after packaging, not using Rcpp::source("cppfile")
3. Packaging code:
R console:
Rcpp::Rcpp.package.skeleton("test", attributes=TRUE, example_code=FALSE, cpp_files="test.cpp")
Rcpp::compileAttributes("test")
CMD console:
REM paths to R/bin/x64 and Rtools/bin, Rtools/mingw_64/bin added to PATH
set PKG_CXXFLAGS=-std=c++11
R CMD build test
R CMD INSTALL test_1.0.tar.gz
ADDITIONAL EDIT:
.Call issues arise as soon as a regex is declared in the C++ code. Using it or no (as in std::regex_match) makes no change.

Answer 1

Can you try disentangling this some more? You are mixing a lot of things here.
Try maybe 'just' C++ from R first, with the newer g++ 4.9.3 compiler and see if that lets you use Boost as you hope. Your use case there is local and non-standard, so you have to work this out. We generally just recommend using BH without linking.
I don't actually see an Rcpp issue here. You are simply pushing the (working, tested, trusted) Rcpp setup into a corner it has not been used in yet. So you may need to work some things out yourself.
Also note that g++ 4.9.3 for R is not really released yet.