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Asked: 2026-06-14T10:24:43+00:00

I’ve found an odd inconsistency between Rcpp which compiled with and without -std=c++0x. Consider

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I’ve found an odd inconsistency between Rcpp which compiled with and without -std=c++0x.

Consider the expression

Function data_frame("data.frame");

GenericVector a;
a.push_back("17");

return data_frame(a, _["stringsAsFactors"]=0);

(ed. note: coercion to DataFrame in Rcpp actually thunks down to the R function, but doesn’t allow the user to set that flag.)

In “old” C++ (w/o -std=c++0x set) this code works. In modern C++ (w/ -std=c++0x set), this fails, saying “cannot coerce class “pairlist” into a data.frame”.

Obviously, this isn’t the end of the world: I just don’t use any newer features. However, I confess to being totally at a loss as to what causes this difference, and how to work around it without throwing C++11 away. Any ideas, anyone?

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1 Answer

  1. Editorial Team

    We love C++11 and cannot wait to use it. But we cannot use it in uploads to CRAN (as per a decree of the CRAN maintainers who consider C++11 “non portable” at this point — please complain to them, not us, of that irks you).

    Consequently it is currently “barred”. There is a bit of detection in RcppCommon.h and we define HAS_CXX0X. But we haven’t really written code for this, as we can’t (yet) per the previous paragraph.

    So if you found a bug, please do us the favor and report it where request follow-ups to be sent: the rcpp-devel list. Reproducible is good, patches even better 🙂

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