Is a C++ destructor guaranteed not to be called until the end of the block?

c++ raii
J Francis picture J Francis · Jan 18, 2010 · Viewed 8.2k times · Source

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

anon picture anon · Jan 18, 2010

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

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