What gets returned?
We don’t know. According to the standard, the behavior is undefined.
ยง6.6.3/2 The return statement
[stmt.return]:
(emphasis mine)
Flowing off the end of a constructor, a destructor, or a function with a cv
void
return type is equivalent to areturn
with no operand. Otherwise, flowing off the end of a function other thanmain
(basic.start.main) results in undefined behavior.
In fact most compilers would give a warning for it, like Clang:
warning: control reaches end of non-void function [-Wreturn-type]