Как установить boost:: необязательный возврат в неинициализированное состояние?

Как я могу "reset" / "unset" a boost::optional?

optional<int> x;

if( x )
{
  // We won't hit this since x is uninitialized
}
x = 3;
if( x )
{
  // Now we will hit this since x has been initialized
}
// What should I do here to bring x back to uninitialized state?
if( x )
{
  // I don't want to hit this
}

Ответы

x = boost::none;

x = optional<int>(); //reset to default

x.reset();