How does C++ exception handling deal with exception derived classes?

Question

If I am catching BaseException will this also catch exceptions which derive from BaseException? Does exception handling care about inheritance, etc, or does it only match the exact exception type being caught?

class MyException {
...
};
class MySpecialException : public MyException {
...
};

---

void test()
{
 try {
 ...
 }
 catch (MyException &e) {
   //will this catch MySpecialException?
 }
}

Answer 1

It's easy to explain with code: http://ideone.com/5HLtZ

#include <iostream>

class ExceptionBase {
};

class MyException : public ExceptionBase {
};

int main()
{
    try
    {
        throw MyException();
    }
    catch (MyException const& e) {
        std::cout<<"catch 1"<<std::endl;
    }
    catch (ExceptionBase const& e) {
        std::cout<<"should not catch 1"<<std::endl;
    }

    ////////
    try
    {
        throw MyException();
    }
    catch (ExceptionBase const& e) {
        std::cout<<"catch 2"<<std::endl;
    }
    catch (...) {
        std::cout<<"should not catch 2"<<std::endl;
    }

    return 0;
}

output:
catch 1
catch 2

Answer 2

C++ exception handling will match the exception subclasses. However, it performs a linear search from the first catch() to the last, and will only match the first one. So if you intend to catch both Base and Derived, you would need to catch(MySpecialException &) first.