Distinguishing ""=default"" from "{}" for Default Constructors and Destructors
While "=default" and "{}" can seem interchangeable for virtual destructors, they exhibit significant differences when used for default constructors and non-virtual destructors.
Default Constructors
For default constructors, "=default" explicitly directs the compiler to generate a default constructor. In contrast, "{}" results in a user-provided default constructor, altering the class's triviness. Trivial classes allow for efficient memory operations, but user-provided functions, including an empty "{}" default constructor, remove this classification.
Destructors
In the case of virtual destructors, "=default" and "{}" have minimal differences. However, for non-virtual destructors, "=default" signifies a compiler-generated destructor, while "{}" indicates a user-provided destructor. This distinction remains crucial in determining the class's triviness, as user-provided destructors prevent trivial classification.
Therefore, when choosing between "=default" and "{}", consider whether the class should be considered trivial or not. "=default" maintains triviness by delegating function generation to the compiler, whereas "{}" creates user-provided functions, impacting the class's triviness status.
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