Specialization of Notype template of type enum- error: template argument is invalid

Question

I have code like this:

  enum GeneratorType
  {
    FILE_LIST, DEVICE
  };

  template<typename SceneT, int TYPE>
  class ODFrameGenerator
  {
  //... some APIS
  };

  template<typename SceneT>
  class ODFrameGenerator<SceneT, GeneratorType::DEVICE>
  {
  //...specialization: ERROR: template argument 2 is invalid
  };

  template<typename SceneT>
  class ODFrameGenerator<SceneT, 1>
  {
  //...specialization: compiles fine!!
  };

I have tried changing template<typename SceneT, int TYPE> in the defination to template<typename SceneT, GeneratorType TYPE> but ist still gives the exact same error. Any idea what is wrong and how to avoid this?

Note: This got compiled with c++11 (with -std=c++11 flag); but is failing otherwise. I am using gcc 4.9.2.

EDIT: The exact error I get is the following:

/home/sarkar/opendetection/common/utils/ODFrameGenerator.h:80:61: error: template argument 2 is invalid
   class ODFrameGenerator<ODSceneImage, GeneratorType::DEVICE>
                                                             ^
/home/sarkar/opendetection/common/utils/ODFrameGenerator.h:100:46: error: wrong number of template arguments (1, should be 2)
   class ODFrameGenerator<ODScenePointCloud<> >, GeneratorType::DEVICE>
                                              ^
/home/sarkar/opendetection/common/utils/ODFrameGenerator.h:28:9: error: provided for ‘template<class SceneT, int TYPE> class od::ODFrameGenerator’
   class ODFrameGenerator
         ^
/home/sarkar/opendetection/examples/objectdetector/od_image_camera.cpp: In function ‘int main(int, char**)’:
/home/sarkar/opendetection/examples/objectdetector/od_image_camera.cpp:28:67: error: template argument 2 is invalid
   od::ODFrameGenerator<od::ODSceneImage, od::GeneratorType::DEVICE> frameGenerator("0");
                                                                   ^
/home/sarkar/opendetection/examples/objectdetector/od_image_camera.cpp:28:83: error: invalid type in declaration before ‘(’ token
   od::ODFrameGenerator<od::ODSceneImage, od::GeneratorType::DEVICE> frameGenerator("0");

Answer 1

You are mixing a few things: if you want to use the enum as not type template parameter you need to specify it in template declaration, like this:

template<typename SceneT, GeneratorType TYPE>
class ODFrameGenerator
{
  //... some APIS
};

Now things can work provided you use Device and not GeneratorType::Device. To use the latter form you need to declare GeneratorType as enum class

enum class GeneratorType
{
    FILE_LIST, DEVICE
};