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int main(int argc, char** argv) {
  try {
    Object object;
    // do useful work
    return 0; // object gets destroyed here
  } catch (...) {
    throw;  
  }
}

Non-Compliant Code Example (throw() Declaration)

A function that declares exception specifications must include every exception that might be thrown during its invocation. If an exception is thrown that is not included in its specification, control automatically reverts to std::unexpected(), which does not return.

In the following code example, the function f() claims to throw exception1 but actually throws exception2. Consequently control flow is diverted to std::unexpected, and the toplevel catch clause may not be invoked. (It is not invoked on Linux with G++ 4.3).

using namespace std;
class exception1 : public exception {};
class exception2 : public exception {};

void f(void) throw( exception1) {
  // ...
  throw (exception2());
}

int main() {
  try {
    f();
    return 0;
  } catch (...) {
    cerr << "F called" << endl;
  }
  return -1;
}

Compliant Solution (throw() Declaration)

The following code example declares the same exception it actually throws

using namespace std;
class exception1 : public exception {};
class exception2 : public exception {};

void f(void) throw( exception1) {
  // ...
  throw (exception1());
}

int main() {
  try {
    f();
    return 0;
  } catch (...) {
    cerr << "F called" << endl;
  }
  return -1;
}

Risk Assessment

Failing to handle exceptions can lead to resources not being freed, closed, etc.

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