[R-pkg-devel] Problem (with complex.h?) under Microsoft Windows

[Duncan Murdoch]

On 13/11/2015 11:24 AM, Pierre Lafaye de Micheaux wrote:
> Dear all,
>
> I created a new version of the package IndependenceTests where I call
> some C and Fortran functions (using the .C() or .Fortran() interface).
> It works perfectly under Linux, with gcc. No problem with R CMD check. I
> would like to upload this package on the CRAN.
>
> But when I first tried to use winbuilder, I got an error with the
> following message:
>
> * installing *source* package 'IndependenceTests' ...
> ** libs
>
> *** arch - i386
> g++  -I"D:/RCompile/recent/R/include" -DNDEBUG
> -I"d:/RCompile/r-compiling/local/local320/include"     -O2 -Wall
> -mtune=core2 -c Cnhat.cpp -o Cnhat.o
> Cnhat.cpp:9:89: error: 'complex' has not been declared
> Cnhat.cpp:9:105: error: two or more data types in declaration of 'res'
> ....
> .....
> etc.
>
>
> I think I understand that there is a problem (only under Windows though)
> with the complex type.
> The beginning of my file Cnhat.cpp is as follows:
>
> 1. #include <R.h>
> 2. #include "Rmath.h"
> 3. #include <complex.h>
> 4. #include <iostream>
> 5. using namespace std;
> 6.
> 7. extern"C" {
> 8.
> 9.   void CnhatC(double *vecs, double *vect, double *X, int *n, int *q,
> int *p, int *vecd, complex double *res) {
> 10.
> 11.    void phinhatReturn(double *vect1, double *vect2, double *vect3,
> double *X, int *q, int *n, double _Complex *res1, double _Complex *res2,
> double _Complex *res3);
> 12.    double _Complex tmp2, prod1 = 1.0 + 0.0*_Complex_I, prod2 = 1.0 +
> 0.0*_Complex_I, somme = 0.0 + 0.0*_Complex_I;
> 13.    int indbeginblocl, l, i, *vecdl, k, j;
> 14.    double *vecsl, *mvectl, *diffvecsvectl, *Xl;
> 15.    double _Complex *res1, *res2, *res3;
> 16.    vecdl = new int[1];
> 17.    res1 =  new _Complex double[1];
> ....
> .....
> etc.
>
> As you can see, there seem to be some problem (on line 9.) with: complex
> double *res
>
> Could you please point me to something (e.g., another package) that
> might help me solve the problem? If possible, I would like to avoid
> invest too much time using the new .Call() interface because I am quite
> familiar
> with the old .C(). And also I am not even sure if it would help solving
> the problem.

You should be using Rcomplex in the type declaration. (See Writing R 
Extensions for a discussion of this.)  It is defined as

typedef struct {
	double r;
	double i;
} Rcomplex;

which is likely compatible with your "complex double" on those other 
systems (which are using newer gcc versions), but it's not guaranteed to 
be, even there.

Duncan Murdoch