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

Question

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

You don\'t pass the array\'s boundaries to delete[]. But where is that information stor

Answer 1

It is not standardized. In Microsoft's runtime the new operator uses malloc() and the delete operator uses free(). So, in this setting your question is equivalent to the following: How does free() know the size of the block?

There is some bookkeeping going on behind the scenes, i.e. in the C runtime.