CUDA and Classes

Question

I\'ve searched all over for some insight on how exactly to use classes with CUDA, and while there is a general consensus that it can be done and apparently is being done by

Answer 1

Define the class in a header that you #include, just like in C++.

Any method that must be called from device code should be defined with both __device__ and __host__ declspecs, including the constructor and destructor if you plan to use new/delete on the device (note new/delete require CUDA 4.0 and a compute capability 2.0 or higher GPU).

You probably want to define a macro like

#ifdef __CUDACC__
#define CUDA_CALLABLE_MEMBER __host__ __device__
#else
#define CUDA_CALLABLE_MEMBER
#endif 

Then use this macro on your member functions

class Foo {
public:
    CUDA_CALLABLE_MEMBER Foo() {}
    CUDA_CALLABLE_MEMBER ~Foo() {}
    CUDA_CALLABLE_MEMBER void aMethod() {}
};

The reason for this is that only the CUDA compiler knows __device__ and __host__ -- your host C++ compiler will raise an error.

Edit: Note __CUDACC__ is defined by NVCC when it is compiling CUDA files. This can be either when compiling a .cu file with NVCC or when compiling any file with the command line option -x cu.