Unable to include LogStream with CasAdi

[Giulero]

Describe the bug

If I include

#include <casadi/casadi.hpp>
#include <yarp/os/LogStream.h>

the following error occurs while compiles:

In file included from /home/giuseppe/robotology-superbuild/build/install/include/yarp/os/all.h:26,
                 from /home/giuseppe/Desktop/IronCub/element_transition-maneouvers/modules/point_mass_opt_test/pointMassOptimizer/include/Solver.h:13,
                 from /home/giuseppe/Desktop/IronCub/element_transition-maneouvers/modules/point_mass_opt_test/pointMassOptimizer/src/Solver.cpp:9:
/home/giuseppe/robotology-superbuild/build/install/include/yarp/os/LogStream.h:238:22: error: redefinition of ‘template<class T> std::ostream& std::operator<<(std::ostream&, const std::vector<T>&)’
  238 | inline std::ostream& std::operator<<(std::ostream& os, const std::vector<T>& t)
      |                      ^~~
In file included from /home/giuseppe/git_repos/casadi/build/install/include/casadi/core/matrix_fwd.hpp:29,
                 from /home/giuseppe/git_repos/casadi/build/install/include/casadi/core/sx_elem.hpp:33,
                 from /home/giuseppe/git_repos/casadi/build/install/include/casadi/core/core.hpp:30,
                 from /home/giuseppe/git_repos/casadi/build/install/include/casadi/casadi.hpp:29,
                 from /home/giuseppe/Desktop/IronCub/element_transition-maneouvers/modules/point_mass_opt_test/pointMassOptimizer/include/Solver.h:12,
                 from /home/giuseppe/Desktop/IronCub/element_transition-maneouvers/modules/point_mass_opt_test/pointMassOptimizer/src/Solver.cpp:9:
/home/giuseppe/git_repos/casadi/build/install/include/casadi/core/casadi_misc.hpp:430:12: note: ‘template<class T> std::ostream& std::operator<<(std::ostream&, const std::vector<T>&)’ previously declared here
  430 |   ostream& operator<<(ostream& stream, const vector<T>& v) {
      |            ^~~~~~~~
make[2]: *** [modules/point_mass_opt_test/pointMassOptimizer/CMakeFiles/TrajOptSolver.dir/build.make:83: modules/point_mass_opt_test/pointMassOptimizer/CMakeFiles/TrajOptSolver.dir/src/Solver.cpp.o] Error 1
make[1]: *** [CMakeFiles/Makefile2:361: modules/point_mass_opt_test/pointMassOptimizer/CMakeFiles/TrajOptSolver.dir/all] Error 2
make: *** [Makefile:150: all] Error 2

Configuration (please complete the following information):

• OS: Ubuntu 20.04
• yarp version: 3.4
• compiler: gcc version 9.3.0

[GiulioRomualdi]

Unfortunately, both yarp and casadi expand std namespace

casadi

https://github.com/casadi/casadi/blob/fadc86444f3c7ab824dc3f2d91d4c0cfe7f9dad5/casadi/core/casadi_misc.hpp#L428-L433

yarp

yarp/src/libYARP_os/src/yarp/os/LogStream.h

Lines 28 to 31 in 13d2bc8

	namespace std {
	template <typename T>
	std::ostream& operator<<(std::ostream& os, const std::vector<T>& t);
	}

Probably the fastest solution avoids using LogStream in your application

cc @traversaro

[traversaro]

Thanks for opening the issue! We had a similar discussion in #2067 .

[drdanz]

That's the same bug, I'm closing this in favour of #2067