[Rcpp-devel] Resolving NativeSymbolInfos from Rcpp (revisited)

[Iñaki Úcar]

2017-07-29 15:02 GMT+02:00 Sokol Serguei <serguei.sokol at gmail.com>:
> Jj Allaire has written at  Sat, 29 Jul 2017 07:58:13 -0400
>
> The best you can do is to get the pointer to the function (not sure if that
> does what you are hoping for):
>
> func <- Rcpp::cppFunction("int foo() { return 1; }")
>
>> body(func)
> .Primitive(".Call")(<pointer: 0x103bf0f40>)
>
> And to narrow even more:
>> Rcpp::cppFunction("int foo() { return 1; }")
>> as.list(body(foo))[[2]]
> <pointer: 0x7f01d493fae0>
> attr(,"class")
> [1] "NativeSymbol"

Oh, I went that far, but I didn't realise that it is already an
externalptr, even if it says "NativeSymbol", isn't it? Thanks, JJ and
Serguei for pointing this out!

2017-07-29 15:22 GMT+02:00 Dirk Eddelbuettel <edd at debian.org>:
>
> Are you aware of what we can do with Rcpp::XPtr and what e.g. the RcppDE
> package does to pass __user-supplied C++ functions__ down to the core of the
> optimization to avoid touching R code?   There is also a Rcpp Gallery piece
> on this: http://gallery.rcpp.org/articles/passing-cpp-function-pointers/

Yes, I am, and I think that my use case is slightly different. My
understanding is, correct me if I'm wrong, that RcppDE implements some
C++ functions and the user is able to choose which one the backend
should use via its name. In my case, the user is the one that would
implement a C++ function for which the backend is unaware: it doesn't
know the name and it's located in another dynamic library.

Iñaki