Question

The answer should be simple, but I wanted to make sure.

Is sizeof() recursive? For instance,

struct foo
{
   DWORD a;
   DWORD b;
};

struct bar
{
   DWORD c;
   foo d;
};

would a sizeof(bar) include the size of foo, returning a full 12 bytes (assuming DWORD is 4 bytes)?

Answer 1

Yes… sizeof gives a total of all the members directly included in the type, including struct/class data members, non-virtual base classes, some implementation-defined links/counters tracking virtual bases, virtual dispatch table pointers, padding that helps align data members for CPU-safe or -efficient access, and theoretically anything else the implementation may feel like putting in there! (for example, something for run-time debugging / error detection, non-Standard support of garbage collection…)

Of course, it doesn’t include the size of pointed-to or referenced objects, but does include the size of those pointers and references.