I posted this on StackOverflow yesterday, but maybe of more interest to
people here:
How to set g++ compiler flags using Rcpp and inline?
http://stackoverflow.com/q/7063265/841830
In lieu of an answer I created ~/.R/Makevars with this single line:
CXXFLAGS = -std=c++0x
That works, but then I realized that ifelse is behaving differently today!
This simple example I posted yesterday:
using namespace Rcpp;
NumericMatrix x(x_);
return wrap(ifelse(x<5,x*x,x));
returned this before:
1 4 9 16 5 6 7 8 9 10 11 12
but in c++0x mode (g++ 3.4) it returns:
0 0 0 0 5 6 7 8 9 10 11 12
Then, Christopher's reply [1] works with normal g++, but crashes with
c++0x mode (see [2] for the error). As I played around with the code I
sometimes got garbage values in the returned matrix instead of a crash.
(-std=gnu++0x behaves the same.)
I took a look at the Rcpp source and the only thing that came to mind is
that exception specifications have been deprecated but the Rcpp code is
using them everywhere. I don't see how that could explain the observed
behaviour though, so I think it must be something more obscure?
Does everyone see the problem with different C++0x compilers, and/or
later versions of g++?
Darren
[1]:
using namespace Rcpp;
NumericMatrix x(x_);
NumericVector y=ifelse(x<5,x*x,x);
y.attr("dim")=Dimension(x.nrow(),x.ncol());
return y;
[2]:
*** caught segfault ***
address 0x300000000, cause 'memory not mapped'
Traceback:
1: .Primitive(".Call")(<pointer: 0x7f36acb327e6>, x_)
2: fun(x)
3: print(fun(x))
4: eval.with.vis(expr, envir, enclos)
5: eval.with.vis(ei, envir)
6: source("test4.R")
--
Darren Cook, Software Researcher/Developer
http://dcook.org/work/ (About me and my work)
http://dcook.org/blogs.html (My blogs and articles)
_______________________________________________
Rcpp-devel mailing list
Rcpp-devel@lists.r-forge.r-project.org
https://lists.r-forge.r-project.org/cgi-bin/mailman/listinfo/rcpp-devel
