How does delete[] "know" the size of the operand array?

Foo* set = new Foo[100];
// ...
delete [] set;

You don't pass the array's boundaries to delete[]. But where is that information stored? Is it standardised?

When you allocate memory on the heap, your allocator will keep track of how much memory you have allocated. This is usually stored in a "head" segment just before the memory that you get allocated. That way when it's time to free the memory, the de-allocator knows exactly how much memory to free.

Stack Overflow Q#197675, score: 234