FAQ 20.04 What is C s destructor discipline?

FAQ 20.04 What is C++'s destructor discipline?

If the class of an object has a destructor, C++ guarantees that the destructor is called when the object dies. A local (auto) object dies at the close of the block ({...}) in which it was created (that is, when it is conceptually popped from the runtime stack). An unbound temporary object dies at the end of the outermost expression in which the temporary was generated (often this is at the next ;). A member object dies when its containing object dies. An array element dies when its array dies. An object allocated via new (dynamically) dies when the object is deleted. With a static object, death occurs sometime after main() finishes.

Everything but dynamically allocated objects (that is, local objects, temporary objects, member objects, static objects, and array elements) are destructed in the reverse order of construction: first constructed is last destructed. In the following example, b's destructor is executed first, then a's destructor.

 void sample() throw() {   Fred a;   Fred b;   // ... } 

Warning: Do not use longjmp with C++ because it subverts the guarantee that destructors will be called.