Cannot convert (*)[] to **

Question

If I create a file:

test.cpp:

void f(double **a) {

}

int main() {
    double var[4][2];
    f(var);
}

And then run: g++ test.cpp -o t

Answer 1

The problem is that a double** is a pointer to a pointer. Your 'f' function wants to be passed the address of a pointer to a double. If you call f(var), well, where exactly do you think that pointer is? It doesn't exist.

This will work:

double *tmp = (double *) var;
f (&tmp);

Also, it would work to change the definition of f:

void f (double a[4][2]) { }

Now f takes a pointer to the kind of array you have. That will work.