Reusing exception handling code in C++

Question

I have these two functions, with duplicated exception treatment, which has the sole purpose of displaying an error message:

void func1() noexcept {
  try {
    do_task();
    do_another_task();
  } catch (const std::out_of_range& e) {
    show_msg("Out of range error", e.what());
  } catch (const std::logic_error& e) {
    show_msg("Logic error", e.what());
  } catch (const std::system_error& e) {
    show_msg("System error", e.what());
  } catch (const std::runtime_error& e) {
    show_msg("Runtime error", e.what());
  } catch (const std::exception& e) {
    show_msg("Generic error", e.what());
  }
}

void func2() noexcept {
  try {
    do_something();
    do_something_else();
    do_even_more();
  } catch (const std::out_of_range& e) {
    show_msg("Out of range error", e.what());
  } catch (const std::logic_error& e) {
    show_msg("Logic error", e.what());
  } catch (const std::system_error& e) {
    show_msg("System error", e.what());
  } catch (const std::runtime_error& e) {
    show_msg("Runtime error", e.what());
  } catch (const std::exception& e) {
    show_msg("Generic error", e.what());
  }
}

I could just handle std::exception and show a single generic message, but I want to be more specific, that's why I'm catching all possible exceptions.

I want to reuse this exception treatment code. I thought about this:

void run_treated(std::function<void()> func) noexcept {
  try {
    func();
  } catch // ... all the catches go here
}

void func1() noexcept {
  run_treated([]()->void {
    do_task();
    do_another_task();
  });
}

void func2() noexcept {
  do_something();
  do_something_else();
  do_even_more();
}

1. Is this a good approach?
2. If so, run_treated will be called a lot. Should I be concerned about performance?
3. Any other approaches?

Answer 1

There's the option of using a Lippincott Function to centralize the exception handling logic. Consider this:

void Lippincott () noexcept {
  try {
    throw;
  } catch (const std::out_of_range& e) {
    show_msg("Out of range error", e.what());
  } catch (const std::logic_error& e) {
    show_msg("Logic error", e.what());
  } catch (const std::system_error& e) {
    show_msg("System error", e.what());
  } catch (const std::runtime_error& e) {
    show_msg("Runtime error", e.what());
  } catch (const std::exception& e) {
    show_msg("Generic error", e.what());
  }
}

void func1() noexcept {
  try {
    do_task();
    do_another_task();
  } catch (...) {
    Lippincott();
  }
}

void func2() noexcept {
  try {
    do_something();
    do_something_else();
    do_even_more();
  } catch (...) {
    Lippincott();
  }
}

How does it work? When you enter the handler in func1 or func2 there is a "current exception" being processed. The body of Lippincott starts a new try..catch block and re-throws it. Then it catches the appropriate exceptions and handles them accordingly in a centralized manner.

You should also note that your exception handling logic isn't really noexcept. There could theoretically be exceptions not covered by your list. In which case there are several places for std::terminate to be called, depending on how you mark things noexcept