Help on interfacing C++ with R

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Hi, I am trying to set up a C++ library for my R code. I followed the 
R-extension manual but found out that the example of "X.cpp, X_main.cpp" 
is somewhat too simple. Here is my code:
Simpler is easier, all this std stuff gets in the way. The problem is that 
R is passing pointers (probably) to doubles, not simple integers. As far 
as I can see, you need to change the 

.C("testIntDivision", 4, 2);

to make sure your numbers are integers (as.integer()) is OK), and the 
function itself (provided that it is visible, and I've no idea if this is 
the case, to pointer arguments:

int testIntDivision(int&, int&); // untried

then pick out the integer values at those addresses. It'll be one or both 
of these problems (I am not fluent in C++, but the same principles apply 
to C). 

I would be concerned about exporting any competing main to load 
dynamically into R too, could you compile the code in two files, one the 
code to load into R, the other with main calling your code, and *only* 
load what needs to be inside R?
 //lib4R.h testing for interfacing C++ with R -- using C++ library in R
#include <iostream>
using namespace std;

class lib4R {
public:
        lib4R();
        ~lib4R();

        int testIntDivision(int, int);
        double testDoubleMultiplication(double, double);

        int getID();
        void setID(int);
private:
        int ID;
};

// lib4R.cpp : Defines the entry points for the library.
#include "lib4R.h"

lib4R::lib4R() {
        cout << "Constructor lib4R()" << endl;
}

lib4R::~lib4R() {
        cout << "Destructor ~lib4R()" << endl;
}

extern "C" {

int lib4R::testIntDivision(int a, int b) {
      return a/b;
}

double lib4R::testDoubleMultiplication(double a, double b) {
        return a*b;
}

int lib4R::getID() {
        return this->ID;
}

void lib4R::setID(int ID) {
        this->ID = ID;
}

int main(int argc, char* argv[])
{
        cout << "Entering main()" << endl;
        lib4R lib1;

        cout << "testIntDivision(4,2) = " << lib1.testIntDivision(4,2) << 
endl;

        return 0;
}

} // extern C

I am working on Windows. I use these to compile the dll with Visual C++:

cl /MT /c lib4R.cpp
link /dll /out:lib4R.dll /export:testIntDivision /export:main lib4R.obj

So when I start rterm.exe:

dyn.load("../lib4R.dll");
.C("main");
Entering main()
Constructor lib4R()
testIntDivision(4,2) = 2
Destructor ~lib4$()
list()

The output is correct, but if I
.C("testIntDivision", 4, 2);
it generated the dialog box claiming "R has encountered a problem and 
needs to be closed.......Please tell Microsoft about this problem....", 
sigh.

So what's wrong with my code, how do I use individual methods/functions of 
C++ in R?

Thanks in advance for any help you can offer!

Bing

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Roger Bivand
Economic Geography Section, Department of Economics, Norwegian School of
Economics and Business Administration, Helleveien 30, N-5045 Bergen,
Norway. voice: +47 55 95 93 55; fax +47 55 95 95 43
e-mail: Roger.Bivand at nhh.no