Is returning void valid code?

Question

I found out that the following code gets accepted by Visual C++ 2008 and GCC 4.3 compilers:

void foo()
{

}

void bar()
{
  return foo();
}

Answer 1

Valid indeed. I use it often for input validation macros:

#define ASSERT_AND_RETURN_IF_NULL(p,r) if (!p) { assert(p && "#p must not be null"); return r; }

bool func1(void* p) {
  ASSERT_AND_RETURN_IF_NULL(p, false);
  ...
}

void func2(void* p) {
  ASSERT_AND_RETURN_IF_NULL(p, void());
  ...
}