[Rcpp-devel] Extract a function from a list and create a call

[Romain Francois]

Le 22/03/10 14:30, Dirk Eddelbuettel a écrit :
>
> On 22 March 2010 at 08:14, Douglas Bates wrote:
> |>  And when I run the code on OSX (gcc 4.2), I get :
> |>
> |>    *** caught segfault ***
> |>  address 0x0, cause 'memory not mapped'
> |>
> |>  Traceback:
> |>    1: .Call("file10d63af1", PACKAGE = f, l)
> |>    2: fx(binomial())
> |>  aborting ...
> |>  Segmentation fault
> |>
> |>  which is not good either.
> |
> | It's likely the segfault occurs when trying to create the std::string
> | from fpt.  A simpler test is
> |
> | suppressWarnings(require(inline))
> | suppressWarnings(require(Rcpp))
> |
> | fx<- cfunction( signature( l = "list" ), '
> |     List ll(l);
> |     CharacterVector fam = ll["family"];
> |     Rprintf("Assigned fam of length %d\\n", fam.size());
> |     if (!fam.size()) return R_NilValue;
> |     char *fpt = fam[0];
> |     Rprintf("(char*)fam[0] points to \\"%s\\"\\n", fpt);
> |     std::string fstr(fpt);
> |     Rprintf("std::string fstr points to \\"%s\\"\\n", fstr.c_str());
> |     return R_NilValue;
> | ', Rcpp = TRUE, includes = "using namespace Rcpp;" )
> |
> | fx(binomial())
> |
> | I think the problem under Linux is extracting fam[0].  The error
>
> Agreed. I tried a few quick variants as well last night without success.
> However, no segfaults on my end.
>
> Dirk

Hello,

I'm confused now because I cannot reproduce the original problem (with 
the script Doug first posted) on fc12 (64 bits) with:

[romain at serifos tmp]$ gcc --version
gcc (GCC) 4.4.3 20100127 (Red Hat 4.4.3-4)

 > version$version.string
R version 2.11.0 Under development (unstable) (2010-03-17 r51295)


.. and the second script also works (prints what I expect).

Romain

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