Conflict between Boost, OpenCV and Eigen libraries?

Question

my question is somewhat related to Static linking of Boost and OpenCV libs with Eclipse CDR. errors, whereas I\'m trying to do a bit more than described here: How to create

Answer 1

Using the boost::filesystem namespace before including Eigen causes the compiler to fail:

#include 
using namespace boost::filesystem;
#include 

fails, but

#include 
#include 
using namespace boost::filesystem;

works.

The reason is that if boost::filesystem is added to the global namespace, it pollutes it, and causes some code (here: eigen) that depends on unpolluted namespace to cause errors during compilation. There's nothing strange about it. Normally you should never put "using" lines before your includes are finished.