C ++：如何获取浮点指针的地址并将其转换为void **

Question

In C++ programming, I often need to acquire the address of a pointer and convert it to void ** . For example, typically when using CUDA:

int main() {
    float *data;
    size_t size = sizeof(float) * 1024;

    CUDA_CHECK(cudaMalloc((void **)&data, size));   // question about this line
    ...
    CUDA_CHECK(cudaFree(static_cast<void *>(data)));

    return 0;
}

My problem is that the cast of a float ** to void ** using C-style type cast irks me, as I don't want to use that in C++ programming.

So far, I've been using reinterpret_cast<void **>(&data) instead, but I'm not happy with it. For some reason I don't think this is the proper way to do it.

I tried doing &static_cast<void *>(data) once very stupidly, as this obviously fails for trying to get the address from a rvalue.

I've done some search on Google and Stack Overflow, but I'm having a hard time finding good keywords for the query.

I've also been learning the concept of rvalue reference, but I don't think it was designed for this problem.

So my question is, what is the proper C++ way to cast from float ** to void ** in this context? Also, is there a way to static_cast to void * and still get the address from the returned value, like rvalue reference? (PS: I still don't quite understand rvalue reference, so forgive me if this is a rookie mistake)

Edit --------------

Sorry I didn't make myself clear. I don't want to declare a void * here. I just want to somehow doing a 'proper' C++ cast to get this done, preferably in just one line.

More Edit ----------

I do understand that using a void * the proper way, as @MM pointed out below (in fact, that's precisely what I've been doing for some time now). I'm just curious if there is any proper way that avoids using void * .

Answer 1

I'd do it this way:

void *newdata;
CUDA_CHECK(cudaMalloc(&newdata, size));
float *data = static_cast<float *>(newdata);

CUDA_CHECK(cudaFree(data)); // or pass newdata, doesn't matter

And obviously I'd wrap those chunks up into a smart pointer with RAII.