C++ new int[0] — will it allocate memory?

Question

A simple test app:

cout << new int[0] << endl;

outputs:

0x876c0b8

So it looks like it works.

Answer 1

I guarantee you that new int[0] costs you extra space since I have tested it.

For example, the memory usage of

int **arr = new int*[1000000000];

is significantly smaller than

int **arr = new int*[1000000000];
for(int i =0; i < 1000000000; i++) {
    arr[i]=new int[0];
}

The memory usage of the second code snippet minus that of the first code snippet is the memory used for the numerous new int[0].