Question

In the C++ code below, am I guaranteed that the ~obj() destructor will be called after the // More code executes? Or is the compiler allowed to destruct the obj object earlier if it detects that it’s not used?

{
  SomeObject obj;
  ... // More code
}

I’d like to use this technique to save me having to remember to reset a flag at the end of the block, but I need the flag to remain set for the whole block.

Answer 1

You are OK with this – it’s a very commonly used pattern in C++ programming. From the C++ Standard section 12.4/10, referring to when a destructor is called:

for a constructed object with
automatic storage duration
when the block in which the object is
created exits