Hi Dirk, thanks for the quick response, there are some clarifications below.
Hi Alexey, > On 12 May 2012 at 19:03, Alexey Stukalov wrote: > |* Dear Rcpp developers, > *| > * *|* ATM to define the Rcpp::Rostream I have to fix the > iostream/Rostream.h header > *|* directly and add > *| > * *|* #include "Rstreambuf.h" > *| > * *|* before its declarations. > *| > * *|* Including "Rstreambuf.h" in my source file before "Rstreambuf.h" > doesn't help, > *|* it seems the headers are processed in a way that Rostream declaration > comes > *|* before Rstreambuf > *|* (due to RcppCommon.h that is included by Rstreambuf.h and not by > Rostream.h). > *| > * *|* Is it possible to fix Rostream.h in the mainline or there's another > proper way > *|* to include it? > * Can you restate your problem a little differently? I don't quite > understand > what you are trying to do, and what is not working. > What do you mean by "define the Rcpp::Rostream" ? You would not have to > include that explicitly as our header structure already does it. See the > example blog post from a few months ago: > http://dirk.eddelbuettel.com/blog/2012/02/18#rcout_armadillo_example > That works the same way with Rcpp alone: > R> library(inline) > R> > R> fun <- cxxfunction(signature(), plugin="Rcpp", body=' > + Rcpp::Rcout << "Hello, world" << std::endl; > + ') > R> > R> cat("Before Rcpp-created function\n") > Before Rcpp-created function > R> fun() > Hello, world > NULL > R> cat("After Rcpp-created function\n") > After Rcpp-created function > R> > R> > That doesn't work so impressively with inline etc as we come back to the > prompt anyway, but by using Rcpp::Rcout all your stdout access from C++ is > passed through the output stream controlled by R thanks to the work Jelmer > did. > Or did I misunderstand and you wanted to do something different ? > I'm trying to use Rcpp::Rostream from my C++ library, not from the inline code, so I have to deal with the headers inclusion on my own :) Basically, I want to use Rostream as a log sink for boost::log (this library not in the mainline boost yet). Because of boost-log API I have to create new Rostream object, using Rcpp::Rcout is not an option. The minimal code that directs log to R console once the library is loaded looks like this: #include <Rcpp/iostream/Rostream.h> #include <boost/log/trivial.hpp> #include <boost/log/sinks.hpp> #include <boost/log/core.hpp> // Called when the library is loaded and before dlopen() returns void __attribute__ ((constructor)) test_load() { // initialize boost-log // Construct the R sink typedef boost::log::sinks::synchronous_sink<boost::log::sinks::text_ostream_backend> text_sink; boost::shared_ptr< text_sink > pRSink = boost::make_shared< text_sink >(); // Add a stream to write log to pRSink->locked_backend()->add_stream( boost::make_shared<Rcpp::Rostream>() ); // Register the sink in the logging core boost::log::core::get()->add_sink(pRSink); BOOST_LOG_TRIVIAL(info) << "R test library loaded"; } // Called when the library is unloaded and before dlclose() returns void __attribute__ ((destructor)) test_unload() { } To make this code work I had to add #include "Rstreambuf.h" into <Rostream.h> for the reasons described above. I hope now it's more clear. > Dirk WBR, Alexey
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