Michel Fortin wrote:
On 2009-02-09 06:41:59 -0500, Ary Borenszweig <a...@esperanto.org.ar> said:How would you do this? X x; if(someCondition) { x = new SomeX(); } else { x = new SomeOtherX(); }Well, the declaration could be transformed to this: X x = new X;But since x is not used before being reassigned (for all code paths), the compiler could just leave it uninitialized until you do the assignement yourself. But then perhaps the "new X" should not be elided unless the constructor and and destructor are pure.
I don't trust that the compiler would do that.
Another question is what happens when X is an abstract class.
Or when X has no default constructor. Or when X's default constructor allocates non-memory resources. Or when X's default constructor depends on global variables that those conditionals set and segfaults or throws when those globals are not in a consistent state. Or when X is a really huge class or does a lot of computation in its constructor and allocating it takes an unreasonable amount of time.
Any case in which the default constructor has side effects or preconditions is a problem.
