[Rcpp-devel] Error in Module

[Romain François]

Hello, 

Just sourceCpp the .cpp file and use the functions verbatim: 

> sourceCpp( "/tmp/mod.cpp" )
> bar(2L)
[1] 4 

If you really want to use the module as an object, you have to pick it up from the right spot: 

> yada <- Module("yada", where = tail(getLoadedDLLs(), 1)[[1]] )
> yada$hello()
[1] "hello"

Romain

Le 8 avr. 2014 à 09:00, Brötje David <d.broetje at tu-braunschweig.de> a écrit :

> Hello,
> 
> 
> I want to expose a C++ class to R through Rcpp. For that I want to try out a few examples from the note "Exposing C++ functions and classes with Rcpp modules" and the book "Seamless R and C++ Integration with Rpp". But I can't manage to get them work. It ends up with an error. So this is what I'm doing.
> 
> First I create a cpp file with the c++ code from the example. The full content of the cpp file is below.
> 
> ------------------------------------------------------------------------------------
> #include "Rcpp.h"
> using namespace Rcpp;
> 
> 
> std::string hello() { return "hello"; }
> 
> int bar( int x) { return x*2; }
> 
> double foo( int x, double y) { return x*y; }
> 
> void bla( ) { Rprintf( "hello\\n" ); }
> 
> void bla1( int x) {
> Rprintf( "hello (x = %d)\\n", x );
> }
> void bla2( int x, double y) {
> Rprintf( "hello (x = %d, y = %5.2f)\\n", x, y );
> }
> 
> 
> RCPP_MODULE(yada) {
> using namespace Rcpp;
> function( "hello" , &hello );
> function( "bar" , &bar );
> function( "foo" , &foo );
> function( "bla" , &bla );
> function( "bla1" , &bla1 );
> function( "bla2" , &bla2 );
> }
> ------------------------------------------------------------------------------------
> 
> 
> Then I run this command:
> 
> 
> PKG_CXXFLAGS=`Rscript -e 'Rcpp:::CxxFlags()'` PKG_LIBS=`Rscript -e 'Rcpp:::LdFlags()'`  R CMD SHLIB test.cpp
> 
> 
> Afterwards I start R and run these commands in R:
> 
> 
> ------------------------------------------------------------------------------------
> require(Rcpp)
> yada <- Module("yada")
> 
> 
> yada$bar( 2L )
> yada$foo( 2L, 10.0 )
> yada$hello()
> yada$bla()
> yada$bla1( 2L)
> yada$bla2( 2L, 5.0 )
> ------------------------------------------------------------------------------------
> 
> 
> And it ends up with this error:
> 
> 
> ------------------------------------------------------------------------------------
> Error in Module(module, mustStart = TRUE) :
>  Failed to initialize module pointer: Error in FUN("_rcpp_module_boot_yada"[[1L]], ...): no such symbol _rcpp_module_boot_yada in package .GlobalEnv
> ------------------------------------------------------------------------------------
> 
> 
> This happens all the time with modules. Did I overlook something or what am I doing wrong?
> 
> 
> David
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