Re: [eigen] Possible Bug ?

I came up with an extreme simple failure case which does not make use of Eigen. I'll report it to GCC's team:

----- func.h -----

#ifndef FUNC_H

#define FUNC_H

namespace Bar {

enum { RowMajor };

template<int Size, int Options = ((Size==1) ? RowMajor : 0)>

class Matrix { };

}

template <int N> void foo(Bar::Matrix<N> &m);

template <> void foo<2>(Bar::Matrix<2> &m);

#endif

---- func.cpp -----

#include "func.h"

template <> void foo<2>(Bar::Matrix<2> &m) {}

---- main.cpp -----

// the namespace is optional

namespace riri { enum { fifi = sizeof(int) }; }

#include "func.h"

int main() {

Bar::Matrix<2> B;

foo<2>(B);

}

$ g++ func.cpp main.cpp

cheers,

Gael

On Tue, Jul 15, 2014 at 1:23 PM, Matthieu Brucher <matthieu.brucher@xxxxxxxxx> wrote:

Hi,

Did you try by changing the order of vector/Eigen headers?

2014-07-15 12:20 GMT+01:00 Helmut Jarausch <jarausch@xxxxxxxxxxxxxxxxxxx>:

> On 07/15/2014 01:02:29 PM, Gael Guennebaud wrote:
>>
>> I found the one line triggering the issue. Using the stackoverflow
>> example,the following main.cpp file is sufficient to trigger the issue:
>>
>>
>> namespace riri { // the namespace is optional
>> enum { fifi = sizeof(int) };
>> }
>>
>> #include "func.h"
>>
>> int main() {
>> std::vector<Eigen::Matrix<double, 2, 2> > m;
>> f<2>(m);
>> }
>>
>>
>> that is, adding the declaration:
>>
>> enum { fifi = sizeof(int) };
>>
>> *before* including Eigen makes gcc's linker nuts.
>>
>> I'm clueless.
>>
>> gael
>>
>
> Probably, I haven't understood the issue.
>
> The following cases compile and link fine with gcc-4.9.0
>
> Case I) gcc Bug1.C
>
> Bug1.C :
>
> #include <Eigen/Dense>
> #include <vector>
>
> template <int N>
> void f(std::vector<Eigen::Matrix<double, N, N> >& m);
>
>
> template <>
> void f<2>(std::vector<Eigen::Matrix<double, 2, 2> >& m) {}
>
> enum { fifi = sizeof(int) };
>
>
> int main() {
> std::vector<Eigen::Matrix<double, 2, 2> > m;
> f<2>(m);
> }
>
>
> Case II) gcc Bug2.C func.C where
>
> Bug2.C :
> #include <Eigen/Dense>
> #include <vector>
>
> template <int N>
> void f(std::vector<Eigen::Matrix<double, N, N> >& m);
>
> enum { fifi = sizeof(int) };
>
>
> int main() {
> std::vector<Eigen::Matrix<double, 2, 2> > m;
> f<2>(m);
> }
>
> func.C :
> #include <Eigen/Dense>
> #include <vector>
> template <int N>
> void f(std::vector<Eigen::Matrix<double, N, N> >& m);
>
> template <>
> void f<2>(std::vector<Eigen::Matrix<double, 2, 2> >& m) {}
>
>
> Helmut
>
>
>

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