using C function from other package in Rcpp

I'm trying to call a C routine from the cubature package in a c++ function to perform multidimensional integration.

The basic R example I'm trying to reproduce is

library(cubature)
integrand <- function(x) sin(x)
adaptIntegrate(integrand, 0, pi)

I could just call this R function from Rcpp following this recipe from the gallery, but there would be some performance penalty in switching back and forth from c/c++ to R. It seems more sensible to directly call the C function from C++.

The C routine adapt_integrate is exported from cubature with

 // R_RegisterCCallable("cubature", "adapt_integrate", (DL_FUNC) adapt_integrate);

I don't understand how to call it from c++, however. Here's my lame attempt,

sourceCpp(code = '
#include <Rcpp.h>
using namespace Rcpp;

// [[Rcpp::export]]
double integrand(double x){
 return(sin(x));
}

// [[Rcpp::depends(cubature)]]
// [[Rcpp::export]]
Rcpp::List integratecpp(double llim, double ulim)
{
  Rcpp::Function p_cubature = R_GetCCallable("cubature", "adapt_integrate");

  Rcpp::List result = p_cubature(integrand, llim, ulim);
  return(result);
}
'
)

integratecpp(0, pi)

This fails to compile; clearly I'm doing something very silly and missing some important steps to convert the output of R_GetCCallable into an Rcpp::Function (or call it directly?). I've read several related posts dealing with function pointers, but haven't seen an example using an external C function.