No newlines in SPARC

[Enchufa2]

I got my hands on a SPARC machine and I've detected that a std::endl issued with Rcpp::Rcout is not printed. I've done the following:

1. Create a test package with Rcpp::Rcpp.package.skeleton("test").
2. Modify src/rcpp_hello_world.cpp as follows:

#include <Rcpp.h>
using namespace Rcpp;

// [[Rcpp::export]]
void rcpp_hello_world() {
  Rcpp::Rcout << "hello world!" << std::endl;
  Rcpp::Rcout << "another hello world!" << std::endl;
}

3. Build the package with R CMD build test.
4. And in the SPARC station...

-bash-3.2$ R CMD INSTALL test_1.0.tar.gz 
* installing to library '/export/home/***/R/sparc-sun-solaris2.10-library/3.3'
* installing *source* package 'test' ...
** libs
/opt/csw/bin/g++-5.2 -I/opt/csw/lib/R/include -DNDEBUG  -I/opt/csw/include -I"/export/home/***/R/sparc-sun-solaris2.10-library/3.3/Rcpp/include"   -fPIC  -O2 -pipe -fno-omit-frame-pointer -mcpu=v9 -Wa,-xarch=v8plus  -c RcppExports.cpp -o RcppExports.o
/opt/csw/bin/g++-5.2 -I/opt/csw/lib/R/include -DNDEBUG  -I/opt/csw/include -I"/export/home/***/R/sparc-sun-solaris2.10-library/3.3/Rcpp/include"   -fPIC  -O2 -pipe -fno-omit-frame-pointer -mcpu=v9 -Wa,-xarch=v8plus  -c rcpp_hello_world.cpp -o rcpp_hello_world.o
/opt/csw/bin/g++-5.2 -shared -mcpu=v9 -Wa,-xarch=v8plus -L/opt/csw/lib -o test.so RcppExports.o rcpp_hello_world.o
installing to /export/home/***/R/sparc-sun-solaris2.10-library/3.3/test/libs
** R
** preparing package for lazy loading
** help
*** installing help indices
** building package indices
** testing if installed package can be loaded
* DONE (test)
-bash-3.2$ Rscript -e "test::rcpp_hello_world()"
hello world!another hello world!-bash-3.2$

No newlines! (I've verified that a simple C++ program using std::cout prints the newlines).

[kevinushey]

Here's the bits of Rcpp's stream buffer implementation that are probably relevant here:

Rcpp/inst/include/Rcpp/iostream/Rstreambuf.h

Lines 60 to 67 in d38a304

	template <> inline std::streamsize Rstreambuf<true>::xsputn(const char *s, std::streamsize num ) {
	Rprintf( "%.*s", num, s ) ;
	return num ;
	}
	template <> inline std::streamsize Rstreambuf<false>::xsputn(const char *s, std::streamsize num ) {
	REprintf( "%.*s", num, s ) ;
	return num ;
	}

Perhaps something funky is going on with how that stream buffer is receiving input? Do you see the same issue with Rcpp::Rcerr?

[Enchufa2]

Same issue with Rcpp::Rcerr, yes. However, I've just tried the following and it's working well:

void rcpp_hello_world() {
  std::ostringstream end;
  end << "\n";
  Rcpp::Rcout << "hello world!" << end.str();
  Rcpp::Rcout << "another hello world!" << end.str();
}

And so does this:

void rcpp_hello_world() {
  Rcpp::Rcout << "hello world!\n";
  Rcpp::Rcout << "another hello world!\n";
}

So maybe the bug is upstream in std::endl?

EDIT: But std::endl works well in a standalone program, outside Rcpp!

[Enchufa2]

Another test I made:

void rcpp_hello_world() {
  Rcpp::Rcout << "hello world!" << std::endl << "X";
  Rcpp::Rcout << "another hello world!" << std::endl << "X";
}

prints

-bash-3.2$ Rscript -e "test::rcpp_hello_world()"
hello world!Xanother hello world!X-bash-3.2$

Which means that std::endl is not being inserted at all. Any idea?

[kevinushey]

Unfortunately no -- since none of us have access to a SPARC machine, it's unlikely that we'll be able to help debug further.

My only suggestion would be for you to copy the streambuf implementation we have in:

https://github.com/RcppCore/Rcpp/blob/d38a304dbc4a6c5d7e7cf4012c63ffe3a364090b/inst/include/Rcpp/iostream/Rstreambuf.h

and try playing around with that until you get the expected output.