Hi,

our project uses libeigen for some linear algebra stuff. Generally we use g++ for compilation but clang++ would be fine too. When we compile with clang++ we get tons of compiler warnings inside of libeigen code. I will give some examples here:

Code: Select all

In file included from /usr/include/eigen3/Eigen/Core:334:
/usr/include/eigen3/Eigen/src/Core/products/GeneralBlockPanelKernel.h:105:5: warning: explicitly assigning a variable of type 'std::ptrdiff_t' (aka 'long') to
      itself [-Wself-assign]
  n = n;
  ~ ^ ~

In file included from /usr/include/eigen3/Eigen/Core:346:
/usr/include/eigen3/Eigen/src/Core/BandMatrix.h:283:86: warning: unused parameter 'cols' [-Wunused-parameter]
    inline BandMatrixWrapper(const CoefficientsType& coeffs, Index rows=_Rows, Index cols=_Cols, Index supers=_Supers, Index subs=_Subs)

So is there a way to silence those warnings related to libeigen code while beeing verbose at our code? How do you handle such situations? Thanks for any suggestions and recommendations.

n=n is probably to avoid 'unused' warnings.
Qt for example avoids these warnings by using this macro:

Code: Select all

    #define Q_UNUSED(arg) (void)arg;

so you can use

Code: Select all

Q_UNUSED(n);

Maybe this is a good approach also for Eigen?

As there are many diffrent warnings, not only related to self assignments, I thought there would be a better way to disable all warnings related to a certain lib...

I also used clang++. My way of processing this is:

clang++ -isystem <the_eigen_path> .....

instead of

clang++ -I<the_eigen_path>

By using -isystem, the compiler will suppress all warnings arising from inside the files in the eigen directory. (The same trick also applies to g++)

Great with CMake and this http://stackoverflow.com/questions/3371 ... with-cmake I got it running and now can focus only our code. Thanks for this hint.

It would also be a good idea to upgrade Eigen. I think that the issues you are referring to were fixed in Eigen 3.0.2, released in August last year. The latest (stable) release is Eigen 3.0.5.