pub type PFN_cusparseSpMV = unsafe extern "C" fn(handle: cusparseHandle_t, op: cusparseOperation_t, alpha: *const c_void, mat_a: cusparseSpMatDescr_t, vec_x: cusparseDnVecDescr_t, beta: *const c_void, vec_y: cusparseDnVecDescr_t, compute_type: cudaDataType, alg: cusparseSpMVAlg_t, external_buffer: *mut c_void) -> cusparseStatus_t;