Should Nested Exceptions Be Used to Handle Exceptions Thrown from Destructors in C ?

Throwing Exceptions from Destructors: The Dilemma of Nested Exceptions

In C , throwing exceptions from destructors poses a particular challenge. When a destructor is invoked, it's possible that another exception is already active. This ambiguity raises the question of how to handle such situations.

Traditionally, C has relied on calling std::terminate or std::terminate_handler when exceptions are thrown from destructors. This approach ensures that any active exceptions are terminated decisively.

However, C 11 introduced std::nested_exception, a feature that enables nesting of exceptions. It was initially considered as a potential solution for handling exceptions from destructors. By nesting the new exception within the active exception, the issue of exception precedence could be resolved.

Despite its potential, this idea was not adopted in C 11 or C 14. The decision was made to maintain the original behavior of calling std::terminate.

Pros and Cons of Nested Exceptions

While nesting exceptions offers the advantage of preserving information from both exceptions, it also comes with potential downsides. For instance, it could introduce unexpected side effects or interfere with the expected behavior of std::terminate.

Alternative Solutions

Currently, there are no plans to revisit the use of nested exceptions for handling exceptions from destructors in C 17. Instead, alternative approaches are recommended, such as:

• Using std::terminate_handler to customize the behavior of std::terminate and potentially recover from the situation.
• Employing techniques like RAII (Resource Acquisition Is Initialization) to ensure that resources are properly released, minimizing the need for exceptions from destructors.

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