I tracked this down to const-ness: bar <- cxxfunction(signature(xs_="character"), plugin='Rcpp', body=' const CharacterVector xs(xs_); const std::string x(xs(0)); Rcout << x << std::endl;')
fails with the compile error mentioned in my last message, while foo <- cxxfunction(signature(xs_="character"), plugin='Rcpp', body=' CharacterVector xs(xs_); std::string x(xs(0)); Rcout << x << std::endl;') foo(month.abb) works fine. I'll be happy to add a unit test to the package if the devs want it. And to go back to my initial qustion: I'm still not sure why "as<std::string>" doesn't work: baz <- cxxfunction(signature(xs_="character"), plugin='Rcpp', body=' CharacterVector xs(xs_); std::string x = as<std::string>(xs(0)); Rcout << x << std::endl;') baz(month.abb) will throw "expecting a string". Davor On 2013-02-07, at 10:27 AM, Davor Cubranic wrote: > On 2013-02-07, at 10:15 AM, Kevin Ushey wrote: > >> One trick to get around this is to 'as' the entire CharacterVector into a >> std::vector< std::string >, and then index based off of that. >> >> My guess is though, elements of CharacterVectors are 'const char*' s, so to >> convert them to strings you might want to just use std::string constructor, >> eg. std::string( xs(0) ). > > That used to work with 0.10.0, but when I upgraded this morning to 0.10.2, > gives me the following compile error: > > rcppdb.cpp:131: error: no matching function for call to > 'std::basic_string<char, std::char_traits<char>, std::allocator<char> > >::basic_string(SEXPREC* const&)' > /usr/include/c++/4.2.1/bits/basic_string.tcc:233: note: candidates are: > std::basic_string<_CharT, _Traits, _Alloc>::basic_string(typename > _Alloc::rebind<_CharT>::other::size_type, _CharT, const _Alloc&) [with _CharT > = char, _Traits = std::char_traits<char>, _Alloc = std::allocator<char>] > /usr/include/c++/4.2.1/bits/basic_string.tcc:226: note: > std::basic_string<_CharT, _Traits, _Alloc>::basic_string(const _CharT*, const > _Alloc&) [with _CharT = char, _Traits = std::char_traits<char>, _Alloc = > std::allocator<char>] > /usr/include/c++/4.2.1/bits/basic_string.tcc:219: note: > std::basic_string<_CharT, _Traits, _Alloc>::basic_string(const _CharT*, > typename _Alloc::rebind<_CharT>::other::size_type, const _Alloc&) [with > _CharT = char, _Traits = std::char_traits<char>, _Alloc = > std::allocator<char>] > /usr/include/c++/4.2.1/bits/basic_string.tcc:208: note: > std::basic_string<_CharT, _Traits, _Alloc>::basic_string(const > std::basic_string<_CharT, _Traits, _Alloc>&, typename > _Alloc::rebind<_CharT>::other::size_type, typename > _Alloc::rebind<_CharT>::other::size_type, const _Alloc&) [with _CharT = char, > _Traits = std::char_traits<char>, _Alloc = std::allocator<char>] > /usr/include/c++/4.2.1/bits/basic_string.tcc:197: note: > std::basic_string<_CharT, _Traits, _Alloc>::basic_string(const > std::basic_string<_CharT, _Traits, _Alloc>&, typename > _Alloc::rebind<_CharT>::other::size_type, typename > _Alloc::rebind<_CharT>::other::size_type) [with _CharT = char, _Traits = > std::char_traits<char>, _Alloc = std::allocator<char>] > /usr/include/c++/4.2.1/bits/basic_string.tcc:183: note: > std::basic_string<_CharT, _Traits, _Alloc>::basic_string(const > std::basic_string<_CharT, _Traits, _Alloc>&) [with _CharT = char, _Traits = > std::char_traits<char>, _Alloc = std::allocator<char>] > /usr/include/c++/4.2.1/bits/basic_string.tcc:191: note: > std::basic_string<_CharT, _Traits, _Alloc>::basic_string(const _Alloc&) [with > _CharT = char, _Traits = std::char_traits<char>, _Alloc = > std::allocator<char>] > /usr/include/c++/4.2.1/bits/basic_string.h:2065: note: > std::basic_string<_CharT, _Traits, _Alloc>::basic_string() [with _CharT = > char, _Traits = std::char_traits<char>, _Alloc = std::allocator<char>] > make: *** [rcppdb.o] Error 1 > > Perhaps this is caused by the same bug, introduced somewhere post-0.10.0. > > Davor > _______________________________________________ > 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
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