On Mon, 13 Mar 2006 [EMAIL PROTECTED] wrote:
> 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
>
> [[alternative HTML version deleted]]
>
> ______________________________________________
> R-devel@r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-devel
>
--
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: [EMAIL PROTECTED]
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