EVOLUTION-MANAGER

Edit File: external_pointer.r

#!/usr/bin/r # # Copyright (C) 2009 - 2010 Romain Francois # # This file is part of Rcpp. # # Rcpp is free software: you can redistribute it and/or modify it # under the terms of the GNU General Public License as published by # the Free Software Foundation, either version 2 of the License, or # (at your option) any later version. # # Rcpp is distributed in the hope that it will be useful, but # WITHOUT ANY WARRANTY; without even the implied warranty of # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the # GNU General Public License for more details. # # You should have received a copy of the GNU General Public License # along with Rcpp. If not, see <http://www.gnu.org/licenses/>. require(Rcpp) require(inline) ## NOTE: This is the old way to compile Rcpp code inline. ## The code here has left as a historical artifact and tribute to the old way. ## Please use the code under the "new" inline compilation section. funx_old <- cxxfunction(signature(), ' /* creating a pointer to a vector<int> */ std::vector<int>* v = new std::vector<int> ; v->push_back( 1 ) ; v->push_back( 2 ) ; /* wrap the pointer as an external pointer */ /* this automatically protected the external pointer from R garbage collection until p goes out of scope. */ Rcpp::XPtr< std::vector<int> > p(v) ; /* return it back to R, since p goes out of scope after the return the external pointer is no more protected by p, but it gets protected by being on the R side */ return( p ) ; ', plugin = "Rcpp" ) xp <- funx_old() stopifnot( identical( typeof( xp ), "externalptr" ) ) # passing the pointer back to C++ funx_old <- cxxfunction(signature(x = "externalptr" ), ' /* wrapping x as smart external pointer */ /* The SEXP based constructor does not protect the SEXP from garbage collection automatically, it is already protected because it comes from the R side, however if you want to keep the Rcpp::XPtr object on the C(++) side and return something else to R, you need to protect the external pointer, by using the protect member function */ Rcpp::XPtr< std::vector<int> > p(x) ; /* just return the front of the vector as a SEXP */ return( Rcpp::wrap( p->front() ) ) ; ', plugin = "Rcpp" ) front <- funx_old(xp) stopifnot( identical( front, 1L ) ) ## NOTE: Within this section, the new way to compile Rcpp code inline has been ## written. Please use the code next as a template for your own project. ## Use of the cppFunction() gives the ability to immediately compile embedded ## C++ directly within R without having to worry about header specification or ## Rcpp attributes. cppFunction(' Rcpp::XPtr< std::vector<int> > funx(){ /* creating a pointer to a vector<int> */ std::vector<int>* v = new std::vector<int> ; v->push_back( 1 ) ; v->push_back( 2 ) ; /* wrap the pointer as an external pointer */ /* this automatically protected the external pointer from R garbage * collection until p goes out of scope. */ Rcpp::XPtr< std::vector<int> > p(v) ; /* return it back to R, since p goes out of scope after the return * the external pointer is no more protected by p, but it gets * protected by being on the R side */ return( p ) ; }') xp <- funx() stopifnot( identical( typeof( xp ), "externalptr" ) ) # passing the pointer back to C++ cppFunction(' SEXP funx_pt(Rcpp::XPtr< std::vector<int> > p){ /* Wrapping x as smart external pointer */ /* The SEXP based constructor does not protect the SEXP from * garbage collection automatically, it is already protected * because it comes from the R side, however if you want to keep * the Rcpp::XPtr object on the C(++) side * and return something else to R, you need to protect the external * pointer, by using the protect member function */ /* Just return the front of the vector as a SEXP */ return Rcpp::wrap(p->front()); }') front <- funx_pt(xp) stopifnot( identical( front, 1L ) )