How to INSTANTIATE_CLASS and REGISTER_LAYER_CLASS

[TingLee91]

I'm new to Caffe and I have met a big problem about how add my own layer. According to the development wiki I should instantiate and register my layer in my cpp file with the macro provided in layer_factory.hpp with "INSTANTIATE_CLASS(MyAwesomeLayer); REGISTER_LAYER_CLASS(MyAwesome);". I don't quite understand this step. Could anybody explain it in a very explicit way or give me an example. Tks.

[shelhamer]

Most layer development questions can be answered by referring to the source of current layers, such as the instantiation and registration of InnerProductLayer: https://github.com/BVLC/caffe/blob/master/src/caffe/layers/inner_product_layer.cpp#L126-L127

[haohao900618]

I have registered new layer VideoDataLayer:
INSTANTIATE_CLASS(VideoDataLayer);
REGISTER_LAYER_CLASS(VideoData);
but got a error when make all as:
src/caffe/layers/video_data_layer.cpp: In function ‘boost::shared_ptrcaffe::Layer caffe::Creator_VideoDataLayer(const caffe::LayerParameter&) [with Dtype = float]’:
src/caffe/layers/video_data_layer.cpp:490: instantiated from here
src/caffe/layers/video_data_layer.cpp:490: error: cannot allocate an object of abstract type ‘caffe::VideoDataLayer’
./include/caffe/video_data_layer.hpp:41: note: because the following virtual functions are pure within ‘caffe::VideoDataLayer’:
./include/caffe/layer.hpp:100: note: void caffe::Layer::Reshape(const std::vectorcaffe::Blob<Dtype_, std::allocatorcaffe::Blob<Dtype_> >&, const std::vectorcaffe::Blob<Dtype_, std::allocatorcaffe::Blob<Dtype_> >&) [with Dtype = float]
./include/caffe/layer.hpp:304: note: void caffe::Layer::Forward_cpu(const std::vectorcaffe::Blob<Dtype_, std::allocatorcaffe::Blob<Dtype_> >&, const std::vectorcaffe::Blob<Dtype_, std::allocatorcaffe::Blob<Dtype_> >&) [with Dtype = float]
./include/caffe/layer.hpp:320: note: void caffe::Layer::Backward_cpu(const std::vectorcaffe::Blob<Dtype_, std::allocatorcaffe::Blob<Dtype_> >&, const std::vector<bool, std::allocator >&, const std::vectorcaffe::Blob<Dtype_, std::allocatorcaffe::Blob<Dtype_> >&) [with Dtype = float]

Anyone knows what's wrong with the error?